ii 
 
Carcass, Sensory, Quality and Instrumental Color Characteristics of Serially Harvested 
Forage-Fed Beef 
 
by 
 
Clinton Wade Rowe 
 
 
 
 
A dissertation submitted to the Graduate Faculty of 
Auburn University 
in partial fulfillment of the 
requirements for the Degree of 
Doctor of Philosophy  
 
Auburn, Alabama 
 December 13, 2010 
 
 
 
 
Keywords: Forage-Fed, Beef, Sensory, Instrumental Color, Fatty Acids, Shear Force 
 
 
 
Copyright 2010 by Clinton Wade Rowe 
 
 
Approved by 
 
Christopher R. Kerth, Chair, Associate Professor of Animal Sciences 
Russell B. Muntifering, Professor of Animal Sciences 
Kyle R. Willian, Affiliate Professor of Animal Sciences 
Christy L. Bratcher, Assistant Professor of Animal Sciences 
 
 
 
ii 
 
Abstract 
 
 Striploins were used in two successive studies to evaluate the effects of serially harvested 
forage-finished steers and forage vs. grain-finished beef.  The first study included six groups of 
steers that were serially harvested over 280 d while grazing forages.  Average daily gain, fiber 
type determination, sensory evaluation, Warner-Bratzler shear force, thiobarbituric acid reactive 
substances (TBARS), fatty acid profile, instrumental color characteristics, and carcass 
characteristics were determined.  Data were analyzed using mixed-model procedures with fixed 
effects of days on forage.  Results indicate that animals that had increased days on forage had 
increased BW, HCW, LM areas and marbling scores.  Fatty acid profiles were impacted by the 
different days on forage.   Forage type appears to have no impact (P > 0.05) on sensory, quality 
or fatty acid profile characteristics in beef.  In the second study, striploins from forage- or grain-
fed cattle were procured for comparison of quality and sensory characteristics.  Striploins were 
aged 21 d and cut into steaks for analyses of fresh and display quality and sensory evaluation to 
determine the effects of both grain-and forage-finishing on fresh and display steaks.  Analyses 
included fresh Warner-Bratzler shear force, sensory evaluation, fatty acid profile, TBARS, and 
display Warner-Bratzler shear force, sensory evaluation and TBARS.  Instrumental color 
characteristics were determined on display steaks while in simulated retail display.  Data were 
analyzed using mixed-model procedures with finishing type and aging period as fixed effects.  
Results indicate that steaks from grain-finished cattle were more tender (P < 0.05) while steaks 
from forage-finished were juicier (P < 0.05).  Steaks from grain-finished cattle had more (P < 
0.05) mg fatty acid / mg meat than steaks from forage-fed cattle.  Steaks from forage-fed cattle
iii 
 
had a lower (P < 0.05) n6:n3 ratio than steaks from grain-finished cattle.  Results from both 
studies indicate that forage-finishing of beef can yield steaks with similar juiciness to grain-
finished beef and greater amounts of n-3 fatty acids.  However, tenderness and consistency issues 
need to be addressed in future research. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
iv 
 
Acknowledgments 
 
 I would like to thank everyone who has helped me during this long and tedious process.  
The ups and downs have made for an exciting ride over the last 10 or so years.  I would like to 
thank Dr. Peter Camfield for seeing the potential in me before I did.  I would also like to thank 
Dr. Fred Pohlman and Dr. A. Hayden Brown, Jr. for their instruction on how to perform 
meaningful research.  I would also like to thank them for allowing me to have this opportunity.  
Without them, none of this would be possible.  I would like to thank Dr. Chris Kerth for his 
direction of this Ph. D. program.  Moreover, I would like to thank him and his family for all of 
their conversation and guidance during this process.  I would like to thank Dr. Russ Muntifering 
and Dr. Christy Bratcher for serving on my committee and offering guidance when needed.  I 
would like to thank Dr. Kyle Willian for serving on my committee and his help and guidance 
with the fatty acid determinations.  I would like to thank the crew at E. V. Smith for their help 
with my projects.  I would like to thank George Richburg at the Beef Teaching Unit for all of his 
help the projects. I would also like to thank the crew at the Meat Lab for their unwavering help 
and support over the last 3 ? years.  Barney, Pete and T.J., you all are the best and it would have 
been extremely difficult to complete this process without you.   A special thanks to Brian Sapp 
and Will Harris at White Oak Pastures, Inc. for their help with the projects.  Thank you to all of 
my fellow graduate students for their help.  I would like to thank my family for their unwavering 
support, and knowing that I would eventually graduate.  I would also like to thank my wife?s 
family for their help and support over the past 2 ? years.  To anyone whom I may have forgotten 
v 
 
in this section, thank you for all of your help and support.  Lastly, I would like to thank my wife 
Amy, for her love and support.   I would especially like to thank Amy for the amount of time that 
she has spent in the lab with me over the past 2 ? years.  Through all of the late nights and 
weekends, you have been there to make sure I had help and conversation. 
 This Doctoral Dissertation is dedicated to my wife, Amy.  Your love and support has 
made this journey much more enjoyable.
vi 
 
 
 
 
 
                                                               Table of Contents 
 
Abstract ........................................................................................................................................... ii 
 
Acknowledgments.......................................................................................................................... iv 
 
List of Tables and Figures............................................................................................................ viii 
 
Chapter I. Introduction .................................................................................................................... 1 
 
Research Objectives ............................................................................................................ 2 
Chapter II. Review of Literature ..................................................................................................... 4 
 
Production Systems ............................................................................................................. 4 
Types of forages, environment and climate ........................................................................ 7 
Muscle Biology Characteristics ........................................................................................ 12 
Color ................................................................................................................................. 15 
Palatability and Quality traits............................................................................................ 19 
Economics ......................................................................................................................... 24 
Chapter III. Sensory, Quality, Instrumental Color and Fiber Type Characteristics of Striploins 
from Serially Harvested Forage-Finished Steers .............................................................. 26 
 
Abstract ............................................................................................................................. 26 
Introduction ....................................................................................................................... 27 
Materials and Methods ...................................................................................................... 28 
vii 
 
Results ............................................................................................................................... 34 
Discussion ......................................................................................................................... 41 
Conclusions ....................................................................................................................... 52 
Chapter IV. Sensory, Quality, and Instrumental Color Characteristics of Striploins from     
Forage-Finished and Grain-Finished Beef ........................................................................ 53 
 
Abstract ............................................................................................................................. 53 
Introduction ....................................................................................................................... 54 
Materials and Methods ...................................................................................................... 55 
Results ............................................................................................................................... 61 
Discussion ......................................................................................................................... 64 
Conclusions ....................................................................................................................... 70 
Chapter V. Implications and Conclusions .................................................................................... 71 
 
Chapter VI. Tables and Figures .................................................................................................... 72 
 
Literature Cited ............................................................................................................................. 93 
 
Appendices .................................................................................................................................. 107 
 
Appendix A. Histochemical Fiber type analyses ............................................................ 108 
Appendix B. Sensory Evaluation form ........................................................................... 111 
Appendix C. Thiobarbituric Reactive Substances Assay ............................................... 112 
Appendix D. Fatty Acid Methyl Esters........................................................................... 114 
 
 
viii 
 
 
 
 
 
                                               List of Tables and Figures 
 
Table 1. Least squares means for carcass characteristics of serially harvested forage-fed           
beef steers.......................................................................................................................... 73 
 
Table 2. Least squares means for instrumental color characteristics of muscle and fat                  
at the 12th rib 24 h postmortem of serially harvested forage-fed beef steers .................... 74 
 
Table 3. Least squares means for group x day interaction for L*, a* and b* values of       
simulated retail display loin steaks of serially harvested forage-fed beef steers .............. 75 
 
Table 4. Least squares means for group x day interaction for Hue Angle, Chroma and       
630/580 nm ratio values of simulated retail display loin steaks of serially             
harvested forage-fed beef steers........................................................................................ 76 
 
Table 5. Least squares means for cook loss, Warner-Bratzler shear force and TBARS of     
serially harvested forage-fed beef steers ........................................................................... 77 
 
Table 6. Least squares means for initial and sustained juiciness for sensory evaluation of    
serially harvested forage-fed beef steers ........................................................................... 78 
 
Table 7. Least squares means for initial and sustained tenderness for sensory evaluation of 
serially harvested forage-fed beef steers ........................................................................... 79 
 
Table 8. Least squares means for beef flavor and off flavor intensity for sensory evaluation of 
serially harvested forage-fed beef steers ........................................................................... 80 
 
Table 9. Least squares means for other and bloody off flavors sensory evaluation of serially 
harvested forage-fed beef steers........................................................................................ 81 
 
Table 10. Least squares means for rancid and grassy off flavors sensory evaluation of serially 
harvested forage-fed beef steers........................................................................................ 82 
 
Table 11. Least squares means for fiber type area and percentage of serially harvested         
forage-fed beef steers ........................................................................................................ 83 
 
ix 
 
Table 12. Least squares means for fatty acid profiles (mg / g meat) of serially harvested     
forage-fed beef steers ........................................................................................................ 84 
 
Table 13. Least squares means for percentage of fatty acid profile of serially harvested       
forage-fed beef steers ........................................................................................................ 85 
 
Table 14. Least squares means for instrumental color characteristics for simulated retail      
display of LM steaks from forage- and grain-finished cattle ............................................ 86 
 
Table 15. Least squares means for fiber type area and percent from striploins of forage- and 
grain-finished cattle .......................................................................................................... 87 
 
Table 16. Least squares means for sensory evaluation, cook loss and Warner-Bratzler shear    
force of LM steaks from forage- and grain-finished cattle ............................................... 88 
 
Table 17. Least squares means for sensory evaluation off flavors, and TBARS of LM steaks   
from forage- and grain-finished cattle .............................................................................. 89 
 
Table 18.  Least squares means for fatty acid profiles (mg / g meat) of from LM from forage-   
and grain-finished cattle .................................................................................................... 90 
 
Table 19. Least squares means for fatty acid profiles (%) of LM from forage- and grain-   
finished cattle .................................................................................................................... 91 
 
Figure 1. Grazing and harvest schedule for the serial harvest of forage-finished steers .............. 92
1 
 
Chapter I 
Introduction 
 
 Cattle have been produced in the United States since the Spaniards brought them up from 
Mexico in the early 1500s (NCBA, 2010).  Traditionally, the basic premise of the production of 
beef cattle through the years has been basically the same with the idea of putting as much weight 
on them as quickly as possible.  For many years, beef cattle grazed native pasture lands all over 
the continental United States and when the cattle were ready, they were shipped to market.  This 
was made famous by the old-time cattle drives that took place in the 1880s and 1890s.  There 
have been many changes since the days of driving cattle.  
 After the Second World War, the cattle industry started to shift toward a more centralized 
feeding strategy (Schupp et al., 1980) that involved using feed grains to increase growth and 
finish on the cattle.  Most of these feedlots are located in the High Plains and Midwest regions of 
the United States (Ward and Schroeder, 2002), because of the abundance of feed grains in the 
region.  This localization of the feeding operations caused a shift in the locations of the packing 
plants that had been located in major cities to be moved closer to the where the cattle are fed 
(Ward and Schroeder, 2002).   
 The feeding section of the beef industry is very efficient in providing high quality beef 
products.  However, in recent years, there has been a demand from consumers and producers to 
produce more forage-fed beef as an alternative to conventional grain-fed beef (ERS-USDA, 
2010).  The southeastern United States climate is not well suited for the production of cattle in a 
dry lot facility much like a feedlot because of the climate and remote distance to the packers and 
2 
 
feedstuffs.  However, this region is very well suited for the production of forages (Allen et al., 
1996).  The southeastern states have a large number of brood cows that produce calf crops every 
year (USDA-NASS, 2007).  For a number of years, these cattle have been sent to the feedlots in 
the High Plains and fed out on grain and harvested.  This makes it virtually impossible for 
producers to keep their investment local, and pits them against producers in various sections of 
the United States.  The idea of finishing beef cattle on forages is far from being a groundbreaking 
or new idea, but the idea of finishing cattle on forages at a commercial level in the 21st century is 
a novel concept.  Over the past several years, the cost of feedstuffs for the beef cattle industry 
have risen dramatically (ERS, USDA, 2009).  In previous years, forage-fed beef was marginally 
economically viable, but with rising cost associated with grain-feeding is now more viable. 
 The lack of widespread consumer acceptance of forage-fed beef over the years has 
occurred because of color of the muscle and fat, flavor and tenderness acceptability (Bowling et 
al., 1977).  Reasons for the lack of consumer acceptance include forage type, growth rate and 
breed of cattle.  The high-concentrate diet in the feedlot allows for many defects that are 
inherently found in an animal or breed to be diluted.  However, that is generally not the case with 
forage-fed beef.  The differences in forage type can have a major impact because of the plant 
constituents within each respective forage type.  These plant constituents can elicit differing 
effects on the resulting meat of an animal, mainly in the fatty acid composition (Dewhurst et al., 
2003).   
Research Objectives 
 
 The use of forage-fed beef growth models has not been used on a large scale for many 
years.  However, with the cost of inputs increasing, the increase in demand from consumers and 
a lack of new relevant research for producers and researchers, two projects were performed. 
3 
 
 The objectives of the first project were to: 1) investigate differences in carcass and 
growth characteristics, fatty acid profiles and instrumental color characteristics of steers grazing 
cool and warm-season forages; 2) investigate effects of multiple aging periods on sensory and 
quality characteristics of steers grazing cool and warm-season forages. 
 The comparison of forage-finished beef with conventional beef was the second project 
undertaken.  The objectives were to: 1) investigate differences in instrumental color 
characteristics during seven days of simulated retail display; 2) compare sensory and quality 
characteristics of conventional and forage-finished beef; 3) compare fatty acid profiles of 
conventional and forage-finished beef. 
4 
 
Chapter II 
Review of Literature 
Production Systems 
 
Forage-Finishing Systems 
 There are many different systems that can be utilized depending on desired results and 
geographic location.  Small grains are typically used in the cooler months of the year, and 
perennial grasses are used in the warmer months of the year.  Differing geographic locations 
generally dictate the type of small grains used.  The High Plains and Midwest regions will 
generally use a variety of wheat because it can be harvested to provide extra income after the 
cattle are removed (Malinowski et al., 2005).  Other areas, where crop production is less 
significant, such as the Southeast, other forages such as rye, oats and annual ryegrass are used. 
 The warm-season forages used in beef production vary depending on geographic 
location.  In the southern United States, bermudagrass (Taliaferro et al., 1974) and bahiagrass 
(Gates et al., 2001) can be used because of the moderate climate that allows these tropical 
grasses to flourish.  In the eastern and northwest part of the United States, grasses such as fescue 
are used for the growing of cattle (Browning, Jr., 2003).   There are advantages and 
disadvantages to each of the forages used.  The tropical grasses such as bermudagrass, 
bahiagrass, and crabgrass are C4 metabolism type plants that require warm temperatures to grow.  
This is good in the summer months, but in spring and fall, production is limited because of 
temperature (Gates et al., 2001).  Fescue is a C3 metabolism type plant that does better in 
moderate temperatures and has peak growth in the late spring and early fall months 
5 
 
(Henning et al., 1993).  Fescue can become less palatable for animals in the hot dry months of 
the summer causing problems when forage production is needed (Henning et al., 1993).  
Endophyte-infection is another disadvantage of fescue. The endophyte-infected fescue causes 
decreased gains in cattle, elevated body temperature and other deleterious effects on cattle 
(Howard et al., 1992).  There are endophyte-free varieties of tall fescue; however these varieties 
are less tolerant of drought conditions and grazing pressures resulting in near complete loss of 
stands within three to four years (Gunter and Beck, 2004).  
Grain-Finishing Systems  
 Grain-finishing systems generally utilize cereal grains as well as some forage crops for 
the feed source.  Grain-finishing allows for more energy to be in the diet compared with forage-
finishing systems (Muir et al., 1998a), which increases cattle growth.  Increased energy intake 
also increases the amount of fat deposition during the finishing phase because of excess energy 
after growing needs are met (Byers, 1982). 
 The feedlot industry has become more concentrated with fewer feedyards causing the 
same amount of cattle being marketed from fewer feedyards that are larger in size (Ward and 
Schroeder, 2002).  This could possibly impact the types of feeds being fed and make the feedlot 
cattle more uniform.   
Effects of forages and grain on growth rate 
 
 The differing forage types (C3, cool-season or C4, warm-season) have different effects 
on the plant growth characteristics with cool-season forages such as fescue having higher 
digestibility than warm-season forages such as bermudagrass (Fisher et al., 1991).  This is 
because of the different components that are found between the forage types with warm-season 
forages having greater concentrations of NDF (Fisher et al., 1991).  The different metabolism 
6 
 
types cause differences in the chemical composition of the plant which affects growth rates of 
the plants (Brown, 1984), which is of major concern because of the different geographic 
locations producing the forage-finished beef.   
 Cattle growth rates from consumption of forages are generally lower than from cattle 
consuming concentrates (Nuernberg et al., 2005; Steen et al., 2003; Mandell et al., 1998), which 
is causes by differences in available energy between the two feedstuffs (Mandell et al., 1998).  
The concentrate diet allows for more energy to be partitioned to growth versus maintenance.  
Mandell et al. (1998) found that when cattle were fed to a final backfat endpoint with two 
scenarios (Scenario 1: Cattle fed high-moisture corn to 4 mm backfat, cattle fed alfalfa silage and 
harvested when cattle fed high-moisture corn reached 4 mm backfat; Scenario 2: Cattle fed 
alfalfa silage to 4 mm backfat, cattle fed high-moisture corn and harvested when cattle fed alfalfa 
silage reached 4 mm backfat; all cattle were fed ab libitum) cattle fed a high-moisture corn diet 
had greater ADG than cattle fed alfalfa silages.  However, carcass weights were different in 
Scenario 1, whereas Scenario 2, cattle carcass weights were not significantly different.  Schaake 
et al. (1993), Schroeder et al. (1980), and Kerth et al. (2007) found that steers fed a concentrate 
diet had heavier carcass weights than steers fed forages.  However, it must be noted that the 
steers fed a concentrate diet in the Schaake study and the Schroeder study were on feed longer 
and were older than their forage-fed counterparts.  This increase in days of feeding is most likely 
the reason for the increase in carcass weights.  However, most literature has a confounding factor 
involved.  These factors generally involve the time of harvest of the cattle.  Some studies 
harvested at a time endpoint (Brown et al., 2005; Mandell et al., 1998), whereas others harvested 
at a backfat or weight endpoint (Kerth et al., 2007; Mandell et al., 1998).  As a result, the grain-
fed animals were generally heavier when harvested at a time endpoint and younger when fed to a 
7 
 
backfat endpoint because of the higher plane of nutrition than their forage-fed counterparts 
(Muir, et al., 1998a).   When cattle are fed only forages with a high, medium or low rate of 
growth, Hersom et al. (2004) reported that cattle reared on a high rate of growth had greater 
carcass weights than that of the other two groups.  French et al. (2000) found that by using 
different levels of forages and grain among five different groups for a constant time basis; 
carcass weights were not significantly different among groups of cattle. 
Types of forages, environment and climate 
 
Carcass Characteristics 
 The amount of growth in cattle being fed at differing planes of nutrition can generally be 
determined through the measurement of ribeye area (REA; Guenther et al., 1965).  The REA and 
backfat measurements allow researchers to determine the amount of saleable meat on a carcass 
(Abraham et al., 1980) and the amount of growth and carcass fat deposition (Guenther et al., 
1965).  Moreover, differing feeding regimes can alter REA and impact overall carcass value with 
the high-concentrate diet yielding a larger REA (Brown et al., 2005).  In cattle fed for the same 
amount of time, Mandell et al. (1998) reported cattle fed a high-concentrate diet will have greater 
REA than that of forage-fed cattle. 
 Hedrick et al. (1983) found that in cattle of similar weight fed corn or forages, the cattle 
fed corn had greater REA than that of the forage-fed cattle.  Likewise, Baublits et al. (2004) 
found that supplementing a forage diet with soyhull pellets when grazing fescue or orchardgrass 
pastures resulted in greater REA than cattle grazing fescue pastures with no supplementation.   
Neel et al. (2007) found that in cattle fed to a similar age, cattle fed in feedlot conditions had 
greater REA than cattle fed forages. However, Steen and Kilpatrick (2000) found that cattle fed 
differing amounts of rolled barley all had similar REA. 
8 
 
Muscle lean color and pH identify potential problems such as DFD (dark, firm and dry) 
appearance of the meat that consumers might find unappealing (USDA, 1997).  In a study using 
1,062 randomly selected cattle from three packing houses, Page et al. (2001) found a moderately 
negative correlation between pH and L* values.  This indicates that as pH values increased, L* 
values decrease caused by decreased light scattering on the surface of the muscle, which makes it 
appear darker.  Vestergaard et al. (2000a), Bruce et al. (2004), and Muir et al. (1998b) all found 
that forage-finished animals had higher pH values than their grain-fed counterparts.  Nuernberg 
et al. (2005) found a breed type x production (forage- vs grain-finishing) interaction for pH.  
However, Varela et al. (2004), Xiong et al. (1996) and Bidner et al. (1981) found no differences 
in L* values between forage- and grain-finished animals. 
Hedrick et al. (1983) found that when cattle of similar weight were fed either corn or 
forage, forage-fed animals had lower L* values or were darker than animals that were fed corn.  
Likewise, Vestergaard et al. (2000a), Varela et al. (2004), and Muir et al. (1998b) found that 
forage-finished cattle were darker than their grain-finished counterparts.  Baublits et al. (2004) 
found that cattle supplemented with soyhulls while grazing either fescue or orchardgrass pastures 
had higher L* values when compared to cattle grazing fescue with no supplementation.  
Likewise, French et al. (2001) and Varela et al. (2004) found no differences between forage- and 
grain-finished cattle. 
 Forage-finished beef generally has more yellow colored fat than grain-finished cattle 
(Kerth et al., 2007; Schaake et al., 1993; Bidner et al., 1986), which is because of carotenoids 
that are found in the plants consumed by the cattle (Yang et al., 1992).  High-concentrate diets 
have a bleaching effect on the fat because of low amounts of carotenoids, which then cause the 
fat to have a white color (Muir et al., 1998b; Craig et al., 1959).  Bidner et al. (1985), Leheska et 
9 
 
al. (2008), and Crouse et al. (1984) found that steers fed a high-concentrate diet had less yellow-
colored fat than steers allowed to graze ryegrass.  Conversely, Baublits et al. (2004) found that 
supplementation of soyhulls to cattle grazing either orchardgrass or fescue had b* values or 
yellowness values similar to cattle grazing fescue only. 
 Forage-finished beef generally has a lower amount of marbling than grain-finished beef 
(Schaake et al., 1993; Bidner et al., 1985, 1986).  This is directly related to the amount of energy 
that is in the diets, with the grain- or high-concentrate diet having more energy than forage diets 
(Mandell et al., 1998; Guenther et al., 1965).  The high-concentrate diet provides for more 
energy to be partitioned to fat accretion (Byers, 1982).  However, with the right combination of 
forage and biological type of cattle, a slight amount of marbling can be achieved (Brown et al., 
2005).    
Kerth et al. (2007) found that cattle grazing ryegrass had similar marbling scores when 
compared with cattle fed a high-concentrate diet.  However, Reagan et al. (1977), Schroeder et 
al. (1980) and Mandell et al. (1998) found that steers fed a concentrate diet had greater amounts 
of marbling than their forage-fed counterparts.  Likewise, Hersom et al. (2004), conducted a 
study using a forage-only model with steers assigned to either a high, medium or low rate of 
growth, reported steers with a high rate of growth had greater amounts of marbling than the other 
groups.  However, the Schaake study and the Schroeder study fed concentrate-finished cattle 
longer and to an older age than the forage-fed cattle. 
 Backfat at the twelfth rib has quality implications because of the occurrences of cold 
shortening of sarcomeres (Jennings et al., 1978), and can be an indicator of the amount of 
intramuscular fat (marbling; Koch et al., 1982).  Forage-finished beef generally has less backfat 
than cattle on high-concentrate diets (Steen et al., 2003; Schroeder et al., 1980; Bowling et al., 
10 
 
1977), which is a function of the amount of energy in the diet (Byers, 1982).  Genetic factors 
also contribute to the amount of fat accretion because of differences in mature size (Brown et al., 
2005).  Brown et al. (2005) suggested that the ideal animal for a forage-finished model would 
most likely be a small to medium biological type because of energy constraints associated with 
forages. 
 Mandell et al. (1993), Bidner et al. (1986), and Realini et al. (2004) found that cattle fed a 
high-concentrate diet had greater amounts of backfat when compared with their forage-fed 
counterparts.  Similarly, Hersom et al. (2004) using a forage-only model with steers on a high, 
medium and low rate of growth, reported that steers fed on a high rate of growth had greater 
amounts of backfat than the other two groups. 
Cool-season forages 
 Cool-season annuals such as annual ryegrass and other small grains like wheat and rye 
can elicit gains of 1.25 kg /d for animals consuming the forage (Beck et al., 2008).  Hafley 
(1996) found using Marshall and Surrey ryegrass that gains of 1.1 to 1.50 kg/d were possible.  
Moreover, Roberts et al. (2009) found gains of 1.09 kg/d for Marshall ryegrass.   
 Fescue, a cool-season perennial is used as a forage, but can decrease ADG compared with 
ryegrass, wheat and rye (Beck et al., 2008).    Lower gains in cattle grazing fescue are generally 
noticed because of the appearance of endophyte in the plant (Realini et al., 2005).  This fungus 
produces a toxin that causes vasoconstriction and leads to increased rectal temperature and 
respiration rate, rough hair coat, and intolerance to heat (Howard et al., 1992).  Realini et al. 
(2005) found that cattle grazing endophyte-infected fescue had decreased average daily gains, 
live weights and hot carcass weights at harvest compared with steers grazing novel endophyte-
infected fescue. 
11 
 
Warm-season forages 
 
 Warm-season forages grow best at warm temperatures in the summer, late spring and 
early fall (Gates et al., 2001).  The C4 plant metabolism pathways allows for greater plant 
growth (Brown, 1984), but as a consequence, changes in plant structure occurs and reduces 
digestibility thereby decreasing animal gains (Forster et al., 1993).  Hill et al. (1993) using Tifton 
78 and Tifton 85 varieties of bermudagrass found gains of 0.65 and 0.67 kg/d, respectively.  
Likewise, Galloway, Sr. et al. (1993) found gains of 1.77 kg/d using bermudagrass. 
Cool vs. Warm-season forages 
 It is generally accepted that the cool-season forages are more digestible than that of 
warm-season forages because of structural differences in the plant (Akin, 1986).  There are 
however drawbacks to both of the forage types.  Most warm-season forages are found in 
established pastures and provide nutrients from late spring through early fall (Gates et al., 2001).  
Annual cool-season forages generally have to be planted in fall, allowed to germinate and 
established before they can grazed.  Moreover, in late spring the plant will mature and the cattle 
will have to be moved or harvested; or if the forage is a dual crop for grain, cattle will have to be 
moved at the first hollow stem stage of maturity so that grain yield is not impacted (Reuter and 
Horn, 2002).  However, some cool-season forages such as fescue are found in established 
pastures with fescue covering approximately 14 million hectares in the US (Thompson et al., 
2001). 
 Forster et al. (1993) found that bermudagrass had greater amounts of NDF than the cool-
season forages of ryegrass and wheat.  The NDF content of forages has been negatively 
correlated with intake of forages and generally decreases gains.  Brown et al. (1997) found that 
bermudagrass pastures produced heavier 205-d wts compared with calves grazing endophyte-
12 
 
infected fescue.  However, that study did not compare forage values, therefore the extent of the 
realized gains from bermudagrass cannot be distinguished on the basis of whether nutritive value 
was greater for bermudagrass or the endophyte in the fescue lowered gains. 
Environment and climate 
 The environmental and climate conditions that cattle are subjected to can have large 
impacts on cattle growth (Winchester, 1964).  Colder climates, especially cold winters can cause 
a shift in the fiber type distributions to a more oxidative state (Lefaucheur and Gerrard, 1998).  
Moreover, cold or hot climates can cause cattle to decrease the amount of intake, thereby 
limiting growth (Winchester, 1964).   
 Winchester (1964) suggested that ambient air temperature has an effect on the amount of 
intake and gains that an animal will realize.  Winchester (1964) noted that the decreased intake 
of feedstuffs was most likely a function of the animal?s body moderating physiological 
temperature by lowering the amount of heat production by means of reduced metabolism.   
Muscle Biology Characteristics 
 
Fiber types 
 Muscle fiber type composition in animals can vary depending on many different factors 
ranging from amount of mobility required to forage (Vestargaard et al., 2000a) to the ambient 
temperature (Lefaucheur and Gerrard, 1998).   As activity increases, fiber types will transition 
from Type IIb ? Type IIx ? Type IIa ? Type Ia and as activity decreases, the transition occurs 
in the opposite direction (Lefaucheur and Gerrard, 1998).  Vestergaard et al. (2000a) found that 
forage-fed cattle had greater percentages of Type Ia fibers and lower percentages of Type IIb 
fibers compared with grain-fed cattle; however, fiber size was similar between the two groups. 
Types of fibers 
 
13 
 
 There are four major types of fibers found in bovine skeletal muscle.  The forms are 
dictated by the myosin heavy chains which have four major isoforms.  The Type I isoforms are 
considered to be slow-twitch and have predominately oxidative metabolism (Lefaucheur and 
Gerrard, 1998).  These fibers are smaller in diameter, very fatigue resistant, and are generally 
found in support and locomotion muscles (Lefaucheur and Gerrard, 1998).  Type Ia fibers are 
generally classified or termed as Type Ia, ?-red or slow-twitch oxidative fiber types (Picard et al., 
2002). 
 Type II fibers make up the other three major fiber types, are considered to be fast-twitch 
(Lefaucheur and Gerrard, 1998) and are larger in diameter than their Type I counterparts 
(Kirchofer et al., 2002; Johnston et al., 1975).  The three major types are Type IIa, Type IIx and 
Type IIb.  Type IIa fibers are considered the intermediate type and are classified as Type IIa, ?-
Red or fast-twitch oxidative-glycolytic (Picard et al., 2002).  Type IIa fibers are an intermediate 
fiber type with a larger diameter than that of the Type Ia fiber (Kirchofer et al., 2002).  Type IIa 
fibers have an oxidative metabolism and are moderately fatigue resistant (Picard et al., 2002). 
 Type IIb and Type IIX are the remaining fiber types to be discussed.  The Type IIx and 
IIb fibers cannot be distinguished from each other when classified using conventional 
histochemical techniques (Picard et al., 2002).  They are large in size with large amounts of 
glycogen storage to assist in their predominately glycolytic metabolism (Picard et al., 2002).  
Type IIb fibers are classified as Type IIb, ?-White, or fast-twitch glycolytic (Picard et al., 2002) 
Effects of fiber types 
 
 The effects of fiber types on meat quality have been studied for many years.  The 
literature shows wide variation with regards to fiber type impact on tenderness in the LM with no 
relationship to any fiber types (Chang et al., 2003, Pork; Wegner et al., 2000, Beef; Whipple et 
14 
 
al., 1990, Beef), Type Ia impacting tenderness (Ryu and Kim, 2005, Pork; Therkildsen et al., 
2002a, Beef) and Type IIb impacting tenderness (Therkildsen et al., 2002a, Beef; Karlsson et al., 
1993, Pork).   
 The distributions of each of the fiber types may have an important role in predicting and 
determining the resulting palatability of the meat.  However, a clear relationship for 
intramuscular fat and tenderness relating to toughness has yet to be fully substantiated (Lee et al., 
2010).  May et al (1977) found no correlations between any fiber type and taste panel tenderness 
or juiciness.  They did, however, find moderately positive correlations between fiber diameter 
and marbling, which indicates that increased growth resulted in increased fat deposition.  
Likewise, Ockerman et al. (1984) found a moderately positive correlation between tenderness 
and oxidative fiber types while the glycolytic fiber types had a moderately negative correlation 
with tenderness.  However, juiciness attributes were not affected. 
 Fiber types can also be shifted depending on intrinsic and extrinsic factors (Lefaucheur 
and Gerrard, 1998).  The most common way of altering fiber type ratios is through extrinsic 
effects such as environment and activity level (Lefaucheur and Gerrard et al., 1998).  Extrinsic 
factors dictate the kind of metabolism needed to meet everyday physiological function, whether 
it is a high level of travel or generation of heat (Lefaucheur and Gerrard, 1998).  The generation 
of heat is during times of cold weather generally done through the use of the tricarboxylic acid 
(TCA) cycle to generate ATP for use of heat production through metabolism (Lefaucheur and 
Gerrard, 1998).  Animals that are required to travel long distances for food and water will also 
have a shift in the ratio of fiber types to the more oxidative types (Vestargaard et al, 2000a).  
This too is because of efficiency for the use of energy.    Vestergaard et al. (2000a) showed in 
LM of cattle using two different production systems (intensive vs. extensive), an increase in 
15 
 
physical activity from the extensive system increased oxidative fiber types while decreasing 
glycolytic fiber types. 
 The growth pattern has been shown to alter both fiber type size and distribution.  Wegner 
et al. (2000) reported that in semitendinosus muscles of cattle that, as age and time on feed 
increased, fiber diameter increased as well; however, they found no differences in fiber type 
distributions.  Similarly, Johnston et al. (1975) found in LM of cattle that, as age and days on 
feed increased, fiber diameter increased for Type Ia fibers only, but fiber type distribution was 
not affected.  Likewise, Vestergaard et al. (2000a) found that fiber type diameter increased as 
time fed increased for Type Ia and Type IIa fibers; however, Type IIb fibers were not affected.  
Conversely, May et al. (1977) found no differences between fiber type diameter and distribution 
in LM of three different breeds of cattle fed for three different time periods.  Therkildsen et al. 
(2002b) found an increase in Type Ia fiber size in LM and supraspinatus muscles of cattle fed a 
higher energy diet compared with cattle fed a lower energy diet.   
Color 
 
Color pigments 
 The color of meat may be the most important attribute affecting consumer purchases 
(Kropf, 1980).  This is because consumers can only see the product in the store, and the color of 
the meat can have a substantial influence on consumers? purchasing decisions (O?Sullivan et al., 
2004).  Consumers are not able to have a sample of the steak to check freshness and tenderness.  
Therefore, the only thing that they have to use in their decision is the color of the meat 
 The color of meat is dictated by myoglobin that is inherently found in meat (Faustman 
and Cassens, 1990).  The differing colors of meat can range from a bright cherry-red to a 
brownish-red color (Faustman and Cassens, 1990).  The bright cherry-red color is caused by 
16 
 
oxymyoglobin ( Mancini and Hunt, 2005; Faustman and Cassens, 1990).  Oxymyoglobin has a 
diatomic oxygen molecule attached at the sixth coordination site of the ferrous heme iron in the 
myoglobin molecule (Mancini and Hunt, 2005).  Deoxymyoglobin causes a purplish color 
because of the lack of a ligand at the sixth coordination site in the ferrous heme iron (Mancini 
and Hunt, 2005).  Metmyoglobin is caused by the heme iron oxidizing from the ferrous (Fe2+) to 
the ferric (Fe3+) state.  The loss of an electron causes the heme iron to be unable to bind an 
oxygen ligand at the sixth coordination site and causes a brown color (Mancini and Hunt, 2005).   
Lipid, myoglobin and protein oxidation 
 The oxidation of lipids and mainly myoglobin result in a product that is found 
undesirable by consumers, causing a loss in sales (Lanari et al., 1996).  Oxidation of both lipids 
(Frankel, 1980) and myoglobin (Mancini and Hunt, 2005) is the result of the loss of an electron.  
This loss causes a conformational change in the myoglobin molecule and results in a brown color 
that consumers find undesirable (Lanari et al., 1996). 
 Lipid oxidation occurs when hydrogen is abstracted from a fatty acid (Frankel, 1980).  
There are two types of oxidation that occur in the meat system, photo-oxidation and auto-
oxidation (Frankel, 1980).  Photo-oxidation is the result of triplet oxygen being converted to an 
excited singlet state, which causes the oxygen molecule to need another electron to be stabilized 
(Frankel, 1980).  The singlet oxygen will then steal an electron from a fatty acid, causing the 
abstracting of hydrogen resulting in a conformational change to the fatty acid (Frankel, 1980).  
Generally, the hydrogen is abstracted from an unsaturated fatty acid with increasing 
susceptibility as the amount of double bonds increase (Frankel, 1980).  The result is that 
saturated fatty acids are the most stable and polyunsaturated fatty acids are the least stable. 
17 
 
 Auto-oxidation is another form of oxidation that occurs in meat.  It is the result of a free-
radical caused by the loss of an electron from another molecule (Frankel, 1980).  Inorganic ions 
and metals will steal an electron from a radical leaving the radical in an excited state (Frankel, 
1980).  The free-radical will then abstract hydrogen and an electron from a fatty acid causing a 
conformational change to the fatty acid (Frankel, 1980). 
  The main differences between the two pathways are that auto-oxidation can be slowed 
or stopped with the addition of chelators or antioxidants, which makes it much easier to control 
and stop.  The pathway after the initial abstraction of hydrogen is similar between the two 
mechanisms.  After the abstraction of the hydrogen and conformational change, the fatty acid 
undergoes transformations and cleavages (Frankel, 1980).  This results in the production of 
aldehydes, ketones and epoxides that are thought to be the cause of off-flavors in meat as a result 
of oxidation (Faustman et al., 2010). 
 The feeding of forages to cattle can increase the amount of antioxidants in the muscle.  
The main antioxidant present from the forages is Vitamin E.  Yang et al. (2002) found no 
differences between steaks from cattle on grain and forage diets supplemented with or without 
2,500 IU vitamin E after seven days of display starting 24 h postmortem.  However, Yang et al. 
(2002) found that, after 47 d aging in a vacuum bag, the steaks from the grain-fed animals 
showed lower TBARS values than the unsupplemented grain- and forage-fed treatments.  In a 
study using two different breed types on either a forage- or concentrate-based diet, Nuernberg et 
al. (2005) found that cattle fed a forage-based diet had lower TBARS values on d 5 and 10 of 
display than their concentrate-fed counterparts. 
 Myoglobin oxidation occurs when the heme iron of the myoglobin protein loses an 
electron (Mancini and Hunt, 2005).  This causes the ferrous (Fe2+) iron to shift to the ferric (Fe3+) 
18 
 
iron state (Faustman and Cassens, 1990).  The result is a conformational change to the 
myoglobin molecule and the heme iron loses the ability to bind a ligand at the sixth coordination 
site (Faustman and Cassens, 1990).  The myoglobin pigment then has a brown color called 
metmyoglobin (Lanari et al., 1996).  The transformation of iron from the ferric to the ferrous 
state and vice versa will occur until muscle antioxidants are expended, which would lead to the 
uninhibited formation of metmyoglobin (Lanari et al., 1996). 
 Faustman et al. (2010) stated that the mechanisms by which lipid oxidation occur could 
enhance the oxidation of myoglobin and have been described mainly through the reactivity of the 
primary and secondary products derived from unsaturated fatty acids.  Moreover, Faustman et al. 
(2010) also stated that from a mechanistic view, the process of oxidation of oxymyoglobin to 
metmyoglobin generates reactive intermediates that can enhance further oxidation of both 
oxymyoglobin and unsaturated fatty acids.  This would in part, explain both off-flavors and 
odors from meat that has undergone some oxidation. 
 Protein oxidation in the muscle has been shown to have deleterious effects on different 
aspects of meat quality, mainly tenderness (Lund et al., 2007).  Two aspects of protein oxidation 
are the polymerization of proteins (Lund et al., 2007) and inactivation of the ?-calpains because 
of the oxidizing of cysteine residues in their active sites (Huff-Lonergan and Lonergan, 2005).  
Protein oxidation is linked to fatty acid oxidation (Viljanen et al., 2004; Srinivasan et al., 1996) 
with products from lipid oxidation such as malondialdehyde modifying proteins (Sayre et al., 
2006).  It would then be possible to postulate that myoglobin oxidation also impacts protein 
oxidation because of the linkage of myoglobin oxidation with lipid oxidation as proposed by 
Faustman et al. (2010). 
19 
 
 Rowe et al. (2004) fed cattle supplemented with and without Vitamin E and with or 
without irradiation, reported that the increased oxidation caused by the irradiation decreased ?-
calpains autolysis.  This decrease in the amount of autolysis of the ?-calpains resulted in the 
increase of shear force values.  Although some of the animals were fed vitamin E, it did not 
increase the amount of autolysis. 
Shelflife 
 The color and shelf-life of meat is one of the most important quality traits of meat 
because of consumer purchasing criteria (Kropf, 1980).  This is because consumers associate the 
appearance of the meat with freshness (Kropf, 1980).   The type of diet that the animal consumes 
has a role in the shelf life of the meat products.  This is because of the types and amounts of fatty 
acids deposited and the amount of antioxidants found in the muscle.  Reagan et al. (1977) found 
when using a visual panel that steaks from forage ?fed cattle had better color scores after six 
days of display than steaks from grain-fed cattle.  Nuernberg et al. (2005) and Gatellier et al. 
(2005) found that forage-fed cattle had lower TBARS values than grain-fed cattle on d 10 and 6, 
respectively.  However, Yang et al. (2002) found no differences between forage-fed and grain-
fed cattle with either no supplementation or supplementation with vitamin E after 7 d of display. 
Palatability and Quality traits 
 
Warner-Bratzler Shear force 
 Warner-Bratzler shear force has been used for years to measure the tenderness of meat.  
While it is effective in offering a repeatable measure (Wheeler et al., 1996), it cannot measure 
juiciness and beef flavor.  Shear force measures the amount of force that is required to slice 
through a piece of meat that it is approximately 1.27 cm thick.  Wheeler et al. (1996) suggested 
that steaks are cooked to the same temperature, allowed to cool, and then five to six 1.27 cm-
20 
 
diameter cores should be taken parallel with the fiber direction and sheared across of the muscle 
fiber direction.  Baublits et al. (2006) found no differences in shear values between cattle 
supplemented with soyhulls on fescue and orchardgrass and cattle grazing fescue only.  Kerth et 
al. (2007), Brown et al. (2007) and Leander et al. (1978) all found that animals fed a high-
concentrate diet produced steaks with lower shear force values compared with animals on a 
forage-fed diet.  However, Bruce et al. (2004), Muir et al. (1998b) and Bidner et al. (1981) found 
no differences between forage- and grain-finished cattle with regard to shear values. 
Sensory evaluation 
 Sensory evaluation has been used for years to evaluate the quality attributes of meat.  
While shear force is a very good and repeatable measure as shown by Wheeler et al. (1996), it 
cannot take into effect intrinsic factors such as flavor and juiciness.  Killinger et al. (2004) found 
that steaks with similar shear force values that had greater amounts of marbling were rated 
juicier, more flavorful and more acceptable than steaks with lower levels of marbling.  The 
differing components of the meat sample as influenced by diet or feeding regime, whether it be 
differing types of forages or grains, can have large impacts.   
 Forage-finishing produced no differences in sensory tenderness compared with grain-
finished animals (French et al., 2001; Davies, 1977; Camfield et al., 1997).  Likewise, Roberts et 
al. (2009) found no differences in sensory tenderness of cattle fed either forage-only or 
supplemented with varying levels of corn while grazing forages.  However, some research has 
shown that grain-fed animals yield more tender steaks than pasture-fed cattle (Kerth et al., 2007; 
Vestergaard et al., 2000b).  Conversely, Bruce et al. (2004) found that forage-finished cattle had 
more tender steaks than grain-finished cattle. 
21 
 
 Juiciness of forage-fed beef compared with grain-fed beef has been shown to be different 
in some research while other research shows no differences.  May et al. (1992) and Nuernberg et 
al. (2005) both found no differences between forage- and grain-fed beef juiciness scores.  
Conversely, grain-fed beef has been shown to be juicier than that of forage-fed beef (Kerth et al., 
2007; Sitz et al., 2005; Mandell et al., 1998). 
 Flavor of forage-fed beef compared with grain-fed beef is quite variable.  May et al. 
(1992) and Nuernberg et al. (2005) both found no differences between forage- and grain-fed beef 
flavor.  In contrast, others have reported grain-fed beef to be more flavorful than forage-fed beef 
(Mandell et al., 1998; Hedrick et al., 1983; Schroeder et al., 1980).  Forages such as those found 
in Flint Hills pasture in Kansas, orchardgrass-clover, rye oats-ryegrass, forage sorghum, 
bluegrass-clover, fescue, fescue-orchardgrassclover, rye ryegrass-clover, arrowleaf clover, 
bermudaclover- sudan, millet and Coastal bermudagrass have been linked to lower or less 
desirable flavor ratings by sensory panels (Melton et al., 1990). 
Fatty Acid Profiles 
 The fatty acid profiles of beef can be influenced by diet (Webb and O?Neill, 2008), but 
the fatty acid profile in beef may not easily be changed because of ruminal biohydrogenation 
(Wood and Enser, 1997).  The fatty acid profiles of monogastric animals can be changed easily 
because the fatty acids are absorbed ?as fed? with little change occurring to the fatty acids 
(Wood et al., 2008).  In beef, the dietary lipids are hydrolyzed by microbial lipases; once 
liberated the unsaturated fatty acids are prone to biohydrogenation and isomerization by the 
rumen bacteria (Harfoot and Hazelwood, 1988).  This results in a large production of stearic acid 
(C18:0), and results in a large proportional difference in the amounts of unsaturated fatty acids in 
the rumen lipids compared with post-ruminal lipids (Harfoot and Hazelwood,1988).  
22 
 
Fincham et al. (2009) found that, when comparing steaks from grain-finished cattle with 
steaks from pasture-finished cattle, amounts of C18:1 cis-9 increased as time on feed increased 
for steaks from grain-finished cattle, but no change was found for steaks from pasture-finished 
cattle.  Furthermore, Fincham et al. (2009) reported that as time on feed increased, the amount of 
C:18:3 n-3 fatty acids increased in steaks from pasture-finished cattle, whereas steaks from 
grain-finished cattle,the amounts of the same fatty acid decreased.   
Ashes et al. (1992), in a study using both in vivo and in vitro analyses, concluded that 
rumen bacteria are unable to efficiently hydrogenate EPA and DHA.  Several studies have 
outlined the fact that PUFAs, particularly the n-3 fatty acids, can bypass the rumen and escape 
unchanged.  Some ways that the PUFAs can escape biohydrogenation is by being encapsulated 
in a seed coat or intact organelle such as a chloroplast (Wood and Enser, 1997).  Wachira et al. 
(2000) noticed using steers fed several different hay diets that some of the C18:3, n-3 fatty acids 
were able to escape the rumen and were incorporated into the fatty acid profile of the steers.  
They concluded that the C18:3n-3 fatty acids were predominately in the glycolipid form which is 
less susceptible to biohydrogenation because of its location in the cell structure.  Moreover, 
Wachira et al. (2000) found that inclusion of linseed oil, which is high in C18:3n-3 nearly 
doubled the amount of C18:3n-3 found in the duodenum compared with the control animals.  
Wachira et al. (2000) speculated that this may be a feasible way of increasing the n-3 fatty acid 
concentrations in the muscle. 
Ashes et al. (1992) concluded that the inability of the rumen microbes to hydrogenate 
EPA and DHA was most likely because of the absence of specific enzymes or steric factors.  
However, it must be noted that Ashes et al. (1992) found that DHA and EPA were not 
incorporated into the muscle triacylglycerides or adipose tissue, but rather in the muscle 
23 
 
phospholipids.  They concluded that since muscle phospholipids make up such a small portion of 
the total fat, even the incorporation of DHA and EPA in the diet and phospholipid layers, it 
would not be enough to provide healthful benefits that are associated with the fatty acids.  
Another way of obtaining DHA and EPA is through the elongation and desaturation of 
C18:3n-3.  Sprecher (2000) reviewed the metabolism of n-3 and n-6 fatty acids and concluded 
that both DHA and EPA can be synthesized from linoleate and linolenate through a series of 
elongations, desaturations and ?-oxidation steps. 
 Conjugated linoleic acids or CLAs have been touted to have positive healthful benefits 
such as antiadipogenic, anticarcinogenic, and anti-inflammatory properties to name a few 
(Bhattacharya et al., 2006).  The potential benefits of these unique isomers have drawn much 
attention in recent years as the population becomes more aware of health aspects of life.  Poulson 
et al. (2004), Maheca et al. (2009), and Fincham et al. (2009) all found that cattle fed a forage 
diet had higher amounts of CLA in their lipid tissue compared with grain-fed animals.  However, 
Warren et al. (2008) found that the grain-fed animals had higher amounts of CLA compared with 
forage-fed animals.   
 Concentrations of the n-6 and n-3 fatty acids have gained in familiarity over the years for 
their prevention of cardiovascular disease (Carroll and Roth, 2002).  The ratio of n-6:n-3 fatty 
acids has been a subject of meat as a potential source of the n-3 fatty acids (Wood et al., 2008).  
Leheska et al. (2008) found that forage-fed cattle had lower n-6:n-3 ratios than their grain-fed 
counterparts.  Noci et al. (2005) found that heifers fed a concentrate diet and then allowed to 
graze forages for differing numbers of days prior to harvest had a negative linear relationship 
between days grazing and n-6:n-3 ratio.  However, Laborde et al. (2001) found Simmental steers 
had higher n-6:n-3 ratios compared with Red Angus steers when fed a common diet.  It must be 
24 
 
noted, that large breed differences may exist, but the data from this paper would only suggest it 
may occur, but could not substantiate it. 
Aging and Protein Proteolysis 
 It has long been accepted that meat that is ?aged? or allowed to set in a refrigerated 
setting for an extended period of time will become more tender (King et al., 2009; Jennings et 
al., 1978).  This is because of the endogenous enzymes that are found in meat called ?-calpain 
(Hopkins and Thompson, 2002).  The calpains degrade the proteins in the myofibrillar matrix of 
the muscle (Geesink et al., 2006).  The ?-calpains are activated with a ?M amount of calcium 
whereas the m-calpains are activated by a mM amount of calcium (for review see Huff-Lonergan 
et al., 2010).   
 There can be great variability among breeds for the amount of proteolysis that will occur; 
the Brahman breed, for example, has a greater amount of calpastatin in the muscle which inhibits 
the calpains, resulting in less tender products (Wheeler et al., 1990).  Another factor that affects 
the amount of proteolysis is implants (Strydom et al., 2009).  Strydom et al. (2009), using three 
different implants, reported that the amount of calpastatin was increased in the three implant 
treatments compared with the non-implanted control.  Moreover, Strydom et al. (2009) also 
reported that the implanted treatments had higher shear force values compared with the non-
implanted control. 
Economics 
 
Consumer Preference 
 Consumer preference for domestic corn-fed beef has been documented by several authors 
(Cox et al., 2006; Umberger et al., 2002).  Umberger et al. (2002) reported that approximately 62 
percent of participants in their study preferred grain-fed beef, however, they also found that 
25 
 
approximately 23 percent of participants preferred Argentine forage-fed beef.  Furthermore, Cox 
et al. (2006) using American grain- and forage-fed beef concluded that approximately one-third 
to one-half of consumers preferred forage-fed beef to grain-fed beef in the southeastern United 
States.  Cox et al. (2006) stated that there was a significant market for forage-fed beef.  These 
available markets would allow producers another option when marketing cattle for optimum 
profit potential.   
26 
 
Chapter III 
 
Sensory, Quality, Instrumental Color and Fiber Type Characteristics of Striploins from Serially  
 
Harvested Forage-Finished Steers 
Abstract 
 
 Fall-born steers (n=60, 317 + 29 kg) were serially harvested to determine the effects of 
days of grazing on sensory, quality, instrumental color and carcass characteristics of steers 
grazing cool- and warm-season forages.  Steers grazed tall fescue until the beginning of the trial 
(Dec. 9, 2008). On the trial start date, steers were stratified by BW and Group 1 (about 12 mo of 
age) was humanely harvested and the remaining groups were placed on ryegrass and harvested 
every 56 d for a total of 6 groups.  On June 23, 2009 steers were moved to a bermudagrass and 
fescue pasture for 28 d and then moved to a crabgrass pasture for the duration of the grazing 
period.  Twenty-four h postmortem, HCW; backfat at the twelfth rib; marbling; LM area; kidney, 
pelvic and heart fat (KPH); bone maturity; pH;  lean and fat L*, a*, b*; and yield grade were 
measured.  Striploins from the left side of the carcass were removed from the carcasses 24 h 
postmortem, vacuum-packaged and aged for 13 d in dark storage at 2o C.  Strip loins were then 
removed from their vacuum packages and cut into 2.54-cm-thick steaks.  The steaks were 
designated to one of three treatments: 14 d aging (14 d), 21 d aging (21 d) or 14 d aging followed 
by display (DIS) for seven d.  The DIS steaks were overwrapped using PVC film on a foam tray.  
Color measurements (L*, a*, b*, hue angle, chroma, and 630/580 nm reflectance ratio) were 
taken on d 0 and 6 of retail display. Data were analyzed for a completely randomized design with 
days of grazing as a fixed effect and data for instrumental color were analyzed using mixed 
27 
 
model procedures with day as a repeated measure and days of grazing as a fixed effect.   Group 6 
had the greatest (P < 0.05) HCW, marbling score, backfat and yield grade compared with other 
groups.  Group 1 had the smallest (P < 0.05) LM area, highest (P < 0.05) pH and the lowest (P < 
0.05) HCW among groups.  Day by Group interactions were significant (P < 0.05) because of 
changes in differences among Groups for all instrumental color characteristics. A treatment by 
Group interaction was significant (P < 0.05) for cooking loss.   Group 2 had a higher (P < 0.05) 
shear value than Groups 1, 4, 5, and 6, but did not differ (P > 0.05) from Group 3.  Results 
indicate that increased days on forage increased HCW, marbling and backfat for Group 6.  Days 
of grazing did not (P > 0.05) increase fiber size after Group 3.  Fatty acid profiles were not 
impacted (P > 0.05) with increased days of grazing. 
Introduction 
 
Forage-finished beef has gained popularity over the past ten years.  The reasons for this 
are numerous, but some of the reasons used most are the increase in input costs of conventionally 
finished beef (Brown et al., 2007), human health (University of California, 2002), animal welfare 
(Vestergaard et al., 2000b) and environmental concerns (USDA-ERS, 2002).  These reasons 
have caused many producers to retain cattle and finish them using forages instead of shipping 
them to the High Plains for feedlot finishing. 
 Tenderness of forage-finished and grain-finished beef has been investigated thoroughly 
showing either no differences (Bidner et al., 1986; Reagan et al., 1977) or grain-finished beef 
being more tender (Kerth et al., 2007; Vestergaard et al., 2000b).  The literature has not yet 
addressed a serial harvest of cattle grazing forages for an extended period of time; however, there 
have been serial harvests of grain-finished beef.  May et al. (1992) found that increased days on a 
28 
 
high-concentrate diet increased backfat thickness, BW, yield grades and dressing percentages.  
However, May et al. (1992) found no improvement in tenderness after 56 d feeding.  
 Other variables that have not been extensively examined are the effects of prolonged 
grazing on muscle fiber types, fatty acid profiles and carcass characteristics.  Vestergaard et al. 
(2000a) found in a comparison of grain-finished cattle with forage-finished cattle that the 
amounts of oxidative fiber types increased in the LM of forage-finished cattle.  The increase in 
activity because of travel required to forage is expected to increase oxidative fiber types 
(Lefaucheur and Gerrard, 1998).  However, it is not yet known if fiber type distributions will 
shift with increased BW and foraging.  The fatty acid profiles of forage-finished beef have been 
investigated with regards to the comparison of grain-finished and forage-finished beef (Fincham 
et al., 2009).  However, a forage-only study has not yet addressed the effects of extended grazing 
on the impacts of the fatty acid profiles. 
 Therefore, the objective of this study was to investigate: 1) the effects of age at harvest 
on the sensory, quality and instrumental color characteristics and 2) the effects of differing aging 
periods and environments on sensory and quality characteristics. 
Materials and Methods 
Animals and Forages 
 Fall-born crossbred steers (n=60) were randomly chosen from the resident herd of the 
Alabama Agricultural Experiment Station E. V. Smith Research Center Beef Unit and assigned 
to one of six harvest dates.  Steers were serially harvested every 56 d using six groups of ten 
head.  Steers were weaned in early fall and allowed to graze fescue and bermudagrass pastures 
until the trial start date.  On trial start date (Dec. 10, 2008), steers were weighed and harvest 
Groups 2 through 6 were placed on ryegrass.  Harvest Group 1 was immediately harvested to 
29 
 
serve as a baseline for the remaining Groups.  Remaining steers were weighed every 28 d and 
were allowed to graze as a sward to eliminate paddock differences.  Steers were monitored 
visually daily to ensure animal health and conformed to the guidelines set forth by the 
Institutional Animal Case and Use Committee (IACUC) protocol number 2008-1490.    
On June 23, 2009, steers were removed from ryegrass and placed on a fescue and 
bermudagrass pasture for 28 d.  Remaining steers (Groups 5 and 6) were then moved to a 
crabgrass pasture for the duration of the project.   All steers were humanely harvested at a USDA 
inspected small commercial processing facility in Bluffton, GA on their respective harvest dates.  
Harvest groups with days of grazing and forage types are presented in Figure 1. 
 Carcass Evaluation  
 Carcass data were recorded 24 h postmortem for each group.  Carcass halves were split 
between the 12th and 13th rib and allowed to bloom for 30 min.  The pH; LM area; lean color; fat 
color; kidney; pelvic and heart fat (KPH); backfat; marbling; and bone maturity were recorded 
by a trained evaluator.  Boneless striploins were then removed from the left side of the carcasses, 
vacuum-packaged and stored at 2o C for 13-d in the dark.   
Sample Processing 
Loins were aged for a total of 14-d.  Steaks were then cut 2.54-cm-thick and assigned to 
treatments.  Treatments included 14-d aging sensory (14 d Sen), shear (14 d Sh) and analytical 
(14 d TBARS); or 21-d sensory(21 d Sen), shear (21 d Sh), and analytical (21d TBARS); and 
display sensory (DIS Sen), shear (DIS Sh) and analytical (DIS TBARS).  The 14 d steaks were 
cut from 14-d-aged loins, vacuum-packaged and frozen immediately.  The 21 d and display 
(DIS) steaks were cut at the same time as the 14 d steaks from the same loins.  The 21 d steaks 
were vacuum-packaged, placed in dark storage and frozen after an additional 7 d.  The DIS 
30 
 
steaks were placed on a #2S Styrofoam tray with a polyabsorbent pad and overwrapped with 
polyvinyl chloride (PVC) film.  The DIS steaks were then placed in a simulated retail display 
case for 7 d and then vaccum-packaged and frozen. 
Instrumental Color and Retail Display 
Steaks (DIS) were placed in a coffin-style retail display case at 4o C for 7 d with the light 
intensity at 1100 1x using Sylvania? Designer Cool White Plus bulbs (F40/DCWP).  
Instrumental color characteristics were recorded on d 0 and 6 using a Hunter Miniscan XE Plus 
(Model 45/0-L, Hunter Associates Laboratory, Inc., Reston, VA, USA).  The CIE L*, a*, and b* 
and reflectance values were determined from the average of two random readings from the 
surface of each steak using Illuminant D65 with a 10o standard observer and a 3.5-cm aperture.  
Hue angle was calculated using tan-1(b*/a*), and saturation index was calculated by square root 
(a*2 + b*2).  The 630/580 nm ratio was calculated by dividing the reflectance value at 630 nm by 
the reflectance value at 580 nm. 
Shear force, cook loss and sensory evaluation 
 Steaks were allowed to thaw for 24 h prior to cooking.  Steaks were then cooked by the 
method of Kerth et al. (2003).  In brief, steaks were cooked on clam-shell-style grills for a 
constant time (6.75 min) to an internal temperature of 71o C.  Steaks were then cooled to 4o C.  
Six 1.27-cm-thick round cores were then removed parallel to the muscle fiber from each steak.  
Cores were sheared once perpendicular to fiber direction using a TA.XT Plus Texture Analyzer 
(Texture Technologies Corp, Scarsdale, NY) with a Warner-Bratzler shear force attachment.   
 Cook loss values were determined by weighing steaks prior to cooking.  After cooking, 
steaks were allowed to cool and were then reweighed.  Cook loss was calculated using the 
following formula. 
31 
 
Fresh weight ? Cooked Weight 
_____________________________________________  x 100 
Fresh Weight 
 
 Sensory evaluation steaks were allowed to thaw for 24 h prior to cooking.  Steaks were 
cooked by the same method described for shear force.  After cooking, steaks were cut into 1.3-
cm x 1.3-cm x steak thickness cubes and placed in a warmer at 65o C for no longer than 20 min. 
 Panelists were trained in accordance with AMSA (1995) guidelines.  Samples were 
assigned random numbers prior to serving.  Panelists were given unsalted crackers and water to 
cleanse their pallets between samples.  Samples were evaluated for initial and sustained 
juiciness, initial and sustained tenderness, flavor intensity, and beef flavor on a scale of 1 to 8, 
with 1 = extremely dry, dry, tough, tough, bland, and extreme off-flavor, and 8 = extremely 
juicy,  juicy, tender, tender, intense, and no off-flavor, respectively.  Off flavors were described 
when identified and are presented as a percentage of the number of times it appeared within a 
sample.  Two samples from each steak were evaluated by panelists in partitioned booths with red 
incandescent light.  
Thiobarbituric Acid Reactive Substances 
 Thiobarbituric acid reactive substances (TBARS) were determined using a modified 
method of Wang et al. (2003).  Five grams of meat free of excess fat and connective tissue were 
homogenized in 15 mL of 7.5% trichloroacetic acid, 0.1% propyl gallate, and 0.1%  EDTA using 
a bullet style blender  (Bella Cucini Rocket Blender, Bella Cucina Artful Food, Inc., Montreal 
Canada) for approximately 30 s.  Samples were then centrifuged at 1,500 x g using a Beckman 
Coulter Allegra X-15 R (Beckman Coulter, Inc., Brea, CA, USA) swinging bucket rotor.  After 
centrifugation, samples were filtered through no. 4 Whatman paper (Whatman, plc, Kent, UK).  
Samples were then loaded into a 96-well microplate (Greneir Bio-one, Frickenhausen, Germany) 
32 
 
in triplicate wells and incubated at 40o C for 130 min in a VWR Incubating Microplate Shaker 
(VWR International, LLC., West Chester, PA, USA).  Microplates were then read using a 
Multiskan EX (Thermo Fisher Scientific, Waltham, MA, USA ) absorbance reader at 540 nm.   
 Standards were made using a stock solution of tetraethoxypropane (TEP) at 1 mM/L.  
The stock solution was diluted to 0, 2, 4, 6, 8, 10, 20, and 30 ?M/mL.  A standard curve was then 
generated for each plate and used for the samples on each respective plate, and results are 
expressed as mg malondialdehyde / kg meat. 
Histochemical fiber type analyses 
 Histochemical fiber type analyses were determined using the method of Solomon and 
Dunn (1988).  At  24 h postmortem, 0.5 cm x 0.5 cm x 1.5 cm cubes were excised from the LM 
parallel to fiber direction and frozen in isopentane chilled in liquid nitrogen and then stored at -
80o C.  Samples were mounted on cork board using freezing gel with fiber orientation 
perpendicular to cork board.  Sections were then cut 10 ?m thick using a Microm HM 505 E 
microtome (Thermo Fisher Scientific, Waltham, MA, USA), transferred to slides and stained.  
Upon completion of staining, slides were covered with a cover slip using glycerol mounting gel.  
Fiber type determinations were then determined using a Motic BA 300 (Motic, Richmond, BC, 
Canada) microscope with a digital camera attachment.  A total of eight pictures were taken from 
each slide so that approximately 100 fibers were represented for analyses.   
 Fibers types were determined by mitochondrial amount and shade of cell.  Darkly shaded 
cells with large amounts of mitochondria were determined to be ?-red fibers.  Fibers that 
displayed moderately dark shading with moderate amounts of mitochondria were determined to 
be ?-red fibers, and lightly shaded fibers with low amounts of mitochondria were determined to 
be ?-white fibers. 
33 
 
 Fiber sizes were determined by calculating total area within the cell.  To obtain an 
accurate measurement, the microscope was calibrated using the certified calibration slide from 
Motic.  Measurements for area are presented as ?m2, and numbers of fibers are presented as 
percentages of total. 
Fatty Acid Profiles 
 Fatty acid profiles were determined using the method of O?Fallon et al. (2007).  One 
gram of muscle tissue was placed in 30 mL glass tube.  Then, 5.3 mL of MeOH, 0.7 mL of 10 N 
KOH, and 2 mg trinondecanoin (C:19:0; internal standard) was added to the sample.  Samples 
were then incubated for 90 min at 55o C in a water bath with a shaker attachment.  Samples were 
then removed and allowed to cool in tap water.  After cooling, 0.58 mL of 24 N H2SO4 was 
added to the sample.  Samples were then incubated in a shaker/water bath for 90 min at 55o C, 
then were removed from water bath, placed in tap water and allowed to cool.  After cooling, 3 
mL of hexane was added to samples.  Samples were then vortex-mixed for 5 min followed by 
centrifugation for 5 min at 1,500 x g.  The hexane layer was then removed and placed in fatty 
acid vials and stored at -20o C until analyses. 
 Fatty acid profiles were determined using an Agilent Technologies 6890N Network GC 
System using a 60m long, 0.25 mm inner diameter, 0.1 ?m film thickness DB-23 High 
Resolution Gas Chromatography column (Agilent Technologies, Santa Clara, CA, USA).  The 
GC was programmed for an oven temperature of 130o C for 1 min, 130-170o C at 6.5o C/ min, 
170-215o C at 2.75o C/ min, 215-230o C at 40o C/ min and had a constant temperature of 230o C 
for 3 min with a split ratio of 50:1.  The detector and injector temperature was set at 250o C. The 
injector was set at 1?L of sample with helium as the carrier gas and a flow rate of 1 mL/min.  
The fatty acid methyl ester (FAME) standards (Nu-Check Prep, Inc.) were ran daily to identify 
34 
 
retention times of FAMEs and the peaks were then integrated so that individual FAMEs could be 
identified.  
Statistical Analyses 
 Data were analyzed using SAS 9.1 (SAS Institute, Inc., Cary, NC, USA).  Instrumental 
color data were analyzed using mixed-model procedures with the fixed effects of days of 
grazing.  Day was treated as a repeated measure.  All other data were analyzed using generalized 
linear models with the fixed effect of days of grazing and aging period.  Least squares means 
were generated using the LSMEANS option of SAS and, when the model P-Value was 
significant (P < 0.05), means were separated using the pair-wise t-test with the PDIFF option in 
SAS.  
Results 
 
Carcass Characteristics 
 Group 6 had the greatest (P < 0.05) BW, and HCW among the groups (Table 1).  Groups 
4 and 5 had similar (P > 0.05) BW and HCW, and had lower (P < 0.05) BW and HCW than 
group 6, respectively.  Groups 2 and 3 had similar (P > 0.05) BW, but group 3 had a greater (P < 
0.05) HCW than group 2.  Group 1 had the lowest (P < 0.05) BW and HCW among the Groups. 
 Group 6 had the greatest amount (P < 0.05) of backfat at the 12th rib and marbling score 
among the groups.  Groups 4 and 5 had similar (P > 0.05) amounts of backfat and marbling 
scores, but were lower (P < 0.05) than group 6.  Groups 1, 2 and 3 had similar (P > 0.05) 
amounts of backfat.  However, Group 1 had lower (P < 0.05) marbling scores than Groups 2 and 
3, which were similar (P > 0.05). 
35 
 
 Group 5 had a greater (P < 0.05) LM area than groups 1, 2, and 3, but was similar (P > 
0.05) to groups 4 and 6.  Groups 3 and 4 had similar (P > 0.05) LM area and Group 1 had the 
smallest (P < 0.05) LM area.  
 Group 6 had a greater (P < 0.05) amount of KPH than Groups 1, 2, 3, and 5, but was 
similar (P > 0.05) to group 4.  Group 1 had lower (P < 0.05) amounts of KPH than Groups 2, 4, 
5, and 6, but was similar (P > 0.05) to Group 3.   Group 1 also had the highest (P < 0.05) 24 h pH 
among the Groups, whereas Groups 2, 3, 4, 5, and 6 had similar (P > 0.05) pH values. 
 Group 6 had the greatest (P < 0.05) yield grade among the Groups.  Groups 1, 2, 4, and 5 
were similar (P > 0.05) and Groups 3 and 5 had similar (P > 0.05) yield grades.  Group 2 had  
greater (P < 0.05) ADG than Groups 3, 5, and 6, but was similar (P > 0.05) to Group 4.  Group 3 
had similar (P > 0.05) ADG to Group 4, and Groups 5 and 6 were similar (P > 0.05), but had 
lower (P < 0.05) ADG than the other Groups. 
 All Groups had similar (P > 0.05) muscle L* values (Table 2).  Group 6 had greater (P < 
0.05) muscle a* value than Groups 1, 3, 4, and 5, but was similar (P > 0.05) to Group 2.  Group 4 
had lower (P < 0.05) muscle a* value than Groups 2 and 5, but was similar (P > 0.05) to Groups 
1, 3 and 4.  Group 2 had a greater (P < 0.05) muscle b* value than Groups 1, 3, 4, and 5, but was 
similar (P > 0.05) Group 6.  Group 4 had a lower (P < 0.05) muscle b* value than Groups 2, 3, 5, 
and 6, but was similar (P > 0.05) Group 1. 
 Group 6 had the highest (P < 0.05) fat L* value, while Groups 2, 3, 4, and 5 were similar 
(P > 0.05).  There were no differences (P > 0.05) for fat a* values among the Groups.  Group 6 
had a higher (P < 0.05) fat b* value than Groups 2 and 4, and was similar (P > 0.05) to Groups 3 
and 5.  Group 4 had a lower (P < 0.05) fat b* value than Groups 3, 5, and 6,  and was similar (P 
> 0.05) to Group 2. 
36 
 
Instrumental Color Characteristics 
 Group x day interactions were significant (P < 0.05) for L*, a*, and b* values (Table 3).  
Group 1 had the lowest (P < 0.05) L* value on d 0, while Group 2 had a higher (P < 0.05) L* 
value than Groups 1, 4, and 6 on d 0, but was similar (P > 0.05) to Groups 3 and 5.  Group 1 had 
a higher (P < 0.05) L* value than Groups 3, 4, 5, and 6 on d 6, but was similar (P > 0.05) to 
Group 2.  Groups 1 and 6 had similar (P > 0.05) a* values on d 0, whereas Groups 2, 3, 4, and 5 
had similar (P > 0.05) a* values on d 0, but were lower (P < 0.05) than Groups 1 and 6.  Groups 
5 and 6 had similar (P > 0.05) a* values on d 6.  Group 1 had the highest (P < 0.05) b* value 
among the Groups on d 0.  Groups 2, 3, 4, and 5 had similar (P > 0.05) b* values on d 0.  Group 
2 had the highest (P < 0.05) b* value on d 6.  Groups 1, 3, and 4 had similar (P > 0.05) b* values 
on d 6, Group 5 had a lower (P < 0.05) b* value than Groups 1, 2, 3, and 4, but was similar (P > 
0.05) to Group 6 on d 6. 
 Group x day interactions were significant (P < 0.05) for hue angle, Chroma, and 630/580 
nm ratio (Table 4).  Group 1 had the highest (P < 0.05) hue angle on d 0 whereas Groups 2, 3, 4, 
5, and 6 had similar (P > 0.05) hue angle values on d 0.  Group 2 had the highest (P < 0.05) hue 
angle value on d 6.  Groups 1, 3 and 6 had similar (P > 0.05) hue angle values and Groups 3 and 
5 had similar (P > 0.05) hue angles values on d 6.  Group 4 had the lowest (P < 0.05) hue angle 
value on d 6.  Group 1 had the highest (P < 0.05) Chroma value on d 0, whereas Groups 2, 3, 4, 
and 5, had similar (P > 0.05) Chroma values on d 0.  Group 2 had the highest (P < 0.05) Chroma 
value on d 6.  Groups 1, 3, and 4 had similar (P > 0.05) Chroma values and Groups 5 and 6 were 
similar (P > 0.05) for Chroma values on d 6.  Group 1 had the greatest (P < 0.05) 630/580 nm 
ratio on d 0 and d 6 among the Groups.  Group 4 had a lower (P < 0.05) 630/580 nm ratio than 
Groups 1, 2, 3 and 5 on d 0 and 6, but was similar (P > 0.05) to Group 6 on both days. 
37 
 
Cook loss, Warner-Bratzler Shear Force and TBARS 
 Group 1 had greater (P < 0.05) amounts of cook loss for all aging periods, but was similar 
(P > 0.05) to Group 2 for the 14-d and 21-d aging periods (Table 5).  Group 3 had a lower (P < 
0.05) amount of cook loss than Groups 1 and 2 for the 14-d aging, but was similar to Groups 4, 
5, and 6.  Group 6 had a lower (P < 0.05) cook loss for the 21-d aging period than Groups 1, 2, 
and 3, but was similar (P > 0.05) to Groups 4 and 5.  Group 5 had a lower (P < 0.05) cook loss 
than Group 1 for the DIS aging period, but was similar (P > 0.05) to Groups 2, 3, 4, and 6.   
 Groups 1 and 5 had similar (P > 0.05) shear values for all aging periods.  Groups 2, 3, 4 
and 6 had decreasing shear values over time and greater (P < 0.05) 14-d shear values than DIS.  
Groups 1, 2, 3, 5 and 6 were similar (P > 0.05) for the DIS and 21-d aging periods.  However, 
Group 4 had lower (P < 0.05) shear values for DIS steaks than its 21-d counterpart.   
 Groups 1, 2, 3, and 4 had similar (P > 0.05) TBARS values for the 14-d aging period and 
Groups 5 and 6 had similar (P > 0.05) values.  All Groups were similar (P > 0.05) for the 21-d 
aging period.  Groups 1 and 2 had similar (P > 0.05) values for the DIS aging period and were 
higher (P < 0.05) than the other Groups.  Groups 3, 4, 5 and 6 had similar (P < 0.05) values for 
the DIS analysis.  
Sensory Evaluation 
 Group x aging period interactions were significant (P < 0.05) for initial and sustained 
juiciness (Table 6).  The Group x aging period interaction occurred because Groups 2, 3 and 4 
had similar (P > 0.05) values for all aging periods, whereas Groups 1, 5, and 6 had at least one 
aging period different (P < 0.05).  The interaction also occurred for sustained juiciness because 
Groups 2, 3, and 6 had similar (P > 0.05) values for all aging periods, whereas Groups 1, 4 and 5 
had at least one aging period different (P < 0.05) from the other analysis.   
38 
 
 Group x aging period interactions for initial and sustained tenderness were not significant 
(Table 7; P > 0.05).  However, because of missing data from Group 3, 21-d analysis treatment, 
means were separated as an interaction because the main effects values are not estimable.  Group 
1 had a higher (P < 0.05) rating for initial and sustained tenderness than Groups 2, 3, 4, and 6 for 
14-d and Groups 2 and 3 DIS steaks, but was similar (P > 0.05) to Group 5 for the 14-d steaks 
and Groups 4, 5, and 6 for the DIS steaks for both initial and sustained tenderness.  Group 3 had 
a lower (P < 0.05) initial tenderness rating for the 14-d aging period than Groups 1, 5 and 6, but 
was similar (P > 0.05) to Groups 2 and 4.  Groups 2 had the lowest (P < 0.05) initial tenderness 
rating for the DIS aging period.  Group 2 also had a lower (P < 0.05) sustained tenderness value 
for the DIS aging period than Groups 1, 4, 5, and 6, but was similar (P > 0.05) to Group 3. 
 There was a Group x aging period trend (P = 0.06) for beef flavor intensity and a Group x 
aging period interaction (P < 0.05) for off flavor intensity (Table 8).  Groups 1, 2, 3, 4, and 5 had 
similar (P > 0.05) values for beef flavor intensity among their respective aging periods whereas 
within Group 6, the 14-d aging period had a lower (P < 0.05) value than the 21-d and DIS aging 
periods.  The Group x aging period interaction for off flavor intensity occurred because Group 6 
had similar (P > 0.05) values among aging periods and the other Groups had differing ranks 
among their respective aging periods.  Group 1 had the highest (P < 0.05) value for the 14-d off 
flavor, whereas Groups 2, 3, 4, 5 and 6 had similar (P > 0.05) off flavor ratings.  Group 5 had a 
higher (P < 0.05) value for the 21-d off flavor than Groups 1, 2, and 6, and was similar (P > 0.05) 
to Group 4.  Group 3 had a higher (P < 0.05) value for DIS off flavor than Groups 1, 2, 5, and 6, 
and was similar (P > 0.05) to Group 4. 
 Groups 1, 4 and 5 had no other off flavors reported (Table 9).  However, Group 2 had 
other off flavors for the 21-d and DIS aging period Groups, Group 3 had other off flavors for the 
39 
 
14-d and DIS aging period Groups, and Group 6 had other off flavors for the DIS aging period 
Group.  All of the reported other off flavors were similar (P < 0.05).  The other off flavors are the 
flavors that appear but are not either salty, grassy, bitter, rancid, metallic, livery or bloody.  The 
other off flavors reported by the panelist were fishy and sour.  There were no differences for 
bloody off flavors among the Groups. 
 The DIS aging period of Group 2 had a higher (P < 0.05) value for rancid off flavors than 
Group 6; however, it was similar (P > 0.05) to the DIS aging periods of Groups 1, 3, 4, and 5 
(Table 10).  Group 4 had the highest (P < 0.05) rancid value for the 21-d aging period among the 
Groups.  There was no (P > 0.05) trend observed for the grassy off flavors.  While there are 
differences (P < 0.05) among the Groups and aging periods, each Group had at least two aging 
periods with similar values.  Group 5 DIS aging period had a higher (P < 0.05) value for grassy 
flavor than Groups 1, 2, 3, and 6, and was similar (P > 0.05) to the DIS aging period Group of 
Group 4. 
Fiber types 
 Group x fiber type interactions were significant (P < 0.05) for both area and percentages 
(Table 11).    The interaction area occurred because Groups 1 and 2 had similar (P > 0.05) values 
for Type Ia fibers and Type IIa fibers, but were different (P < 0.05) for Type IIb fibers.  
Likewise, Groups 3, 4, 5, and 6 had similar (P > 0.05) values for Type Ia and Type IIa fibers, 
respectively.  Group 3 had greater (P < 0.05) areas for Type Ia, Type IIa and Type IIb fibers than 
Groups 1 and 2,  but was similar (P > 0.05) to Groups 4, 5 and 6 for Type Ia, Groups 4 and 5 for 
Type IIa and Groups 4 and 5 for Type IIb fibers.  The interaction of Group x fiber type 
percentages occurred because of percentages of the Type Ia and Type IIb fibers were different 
among Groups.  Groups 1, 4, and 6 had similar (P > 0.05) percentages of Type Ia and Type IIb 
40 
 
fibers whereas Groups 2 and 3 had higher (P < 0.05) percentages of Type Ia fibers than Type IIb.  
Group 5 had a lower (P < 0.05) percentage of Type Ia fibers than Type IIb fibers.  Type IIa fibers 
were similar (P > 0.05) among the Groups.  Group 2 had a higher (P < 0.05) percentage of Type 
IIa fibers than Groups 4 and 5 and was similar (P > 0.05) to Groups 1, 3, and 6.  Group 5 had a 
higher (P < 0.05) percentage of Type IIb fibers than Groups 2, 3, and 6, but was similar (P > 
0.05) to Groups 1, and 4. 
Fatty Acid Profiles 
 Results for fatty acid profiles for mg / g meat and percent of profile are presented in 
Tables 12 and 13, respectively.  Group 3 had a greater (P < 0.05) amount of C:16:1 t than Groups 
1 and 6, while having a similar (P > 0.05) value to Groups 2, 4, and 5.  Group 5 had a greater (P 
< 0.05) amount of C:18:1 n7 than Group 1, while having similar (P > 0.05) values to Groups  2, 
4, 5 and 6.  Group 1 a higher (P < 0.05) value for C:18:2 n6 than Groups 2, 3, 4 and 6, while 
being similar (P > 0.05) to Group 5.  Group 5 had a greater (P < 0.05) value than Group 6 for 
C:18:3 n3 while being similar (P > 0.05) to Groups 1, 2, 3, and 4.  Group 1 had a higher (P < 
0.05) value for C:20:3 n6 than Groups 3, 4, and 6, but was similar (P > 0.05) to Groups 2, and 5.  
Likewise, Group 1 had a greater (P < 0.05) value for C:20:4 than Groups 2, 4, and 6, while being 
similar (P > 0.05) to Groups 3, and 5.  Group 5 had a higher (P < 0.05) value than Group 6 for 
C:22:0 but was similar (P > 0.05) to Groups 1, 2, 3, and 4.  Group 4 had a greater (P < 0.05) 
amount of C:22:5 than Groups 2 and 6, while being similar (P > 0.05) in value to Groups 1, 3, 
and 5.  All Groups were similar (P > 0.05) for total amounts of saturated fatty acids and 
monounsaturated fatty acids.  However, Group 5 had a greater (P < 0.05) amount of 
polyunsaturated fatty acids than Groups 2, 3, 4, and 6, but was similar (P > 0.05) to Group 1.  
41 
 
Group 6 had a higher (P < 0.05) n6:n3 ratio than Groups 2, 3,4, and 5,  but was similar (P > 0.05) 
to Group 1. 
 Group 1 had a higher (P < 0.05) percentage of 14:0 than Groups 3, 4, and 5 and was 
similar (P > 0.05) to Groups 2, and 6.  Group 6 had a greater (P < 0.05) percentage of 16:0 and 
was similar to Group 4.  Group 3 had the highest (P < 0.05) percentage of 16:1 t among the 
Groups.  Group 6 had a greater (P < 0.05) percentage of 18:1 n9 than Group 3, but had similar (P 
> 0.05) values to Groups 1, 2, 4, and 5.  Group 3 had a higher (P < 0.05) percentage of 18:2 n6 
than Groups 4 and 6, and was similar (P > 0.05) to Groups 1, 2 and 5.  Likewise, Group 3 had a 
greater (P < 0.05) percentage of 18:3 n3 than Groups 1, 4, 5 and 6,  and was similar (P > 0.05) to 
Group 2.  Group 3 had a greater (P < 0.05) percentage of 20:2 than Groups 2, 5, and 6, but was 
similar (P > 0.05) to Groups 1, and 4.  Group 3 also had  higher (P < 0.05) percentages of 20:4 
and 20:3 n6 than Groups 4, 5 and 6, but was similar (P > 0.05) to Groups 1 and 2, respectively.  
Group 3 had the greatest (P < 0.05) amount of 22:0 and 22:5 and was different from all other 
Groups.  Group 6 had a greater (P < 0.05) percentage of saturated fatty acids than Group 3, but 
had similar (P > 0.05) values to Groups 1, 2, 4 ,and 5.  Group 6 also had a higher (P < 0.05) 
percentage of monounsaturated fatty acids than Groups 1, 2, and 3, and was similar (P > 0.05) to 
Groups 4 and 5.  Group 3 had a greater (P < 0.05) amount of polyunsaturated fatty acids than 
Groups 2, 4, 5 and 6, but was similar (P > 0.05) to Group 1. 
Discussion 
 
Carcass Characteristics 
 Greater BW as well as HCW from Groups 4, 5, and 6 were expected because the Groups 
were older at time of harvest and had a greater number of days grazing forages.  The literature 
supports this conclusion, as a number of authors have found this same result with both forages 
42 
 
and grain (Therkildsen et al., 1998; Westerling and Hedrick, 1979; Harrison et al., 1978).  
Moreover, the differences in the Groups in backfat measurement suggests that the rate of muscle 
growth had slowed and the rate of fat accretion had increased.  This is further supported by the 
fact that the amounts of backfat continued to increase with Group 6 having more than the other 
Groups, whereas Groups 4, 5, and 6 were all similar for LM areas.  Moreover, it is supported by 
the marbling scores of the cattle.  With the exception of Group 1 for marbling scores, backfat 
thickness and marbling scores were similar.  This would also indicate that, as cattle age and days 
on forage increased, the amount of fat deposition increased as well.  Moreover, the amount of 
growth from protein accretion slowed, allowing more energy from the diet to be partitioned to fat 
accretion.  Therkildsen et al. (1998), Duckett et al. (1993), and Harrison et al. (1978) all found 
that as days on feed increased, the amounts of backfat, LM area and marbling scores also 
increased. 
 Group 1 had greater 24-h pH values than the other Groups.  This is most likely because of 
the low plane of nutrition that the first Group experienced prior to the trial start date.  As detailed 
in the Materials and Methods section, the steers were held on a predominately fescue and 
bermudagrass pasture and the trial start date was Dec. 10.  These forages would have very low 
nutritive levels at this time during the year (Gates et al., 2001; Hennig et al., 1993).  This low 
plane of nutrition would most likely cause low levels of glycogen stores in the muscles.  This 
would then cause a lack of available glycogen stores immediately postmortem and would result 
in a failure of pH decline (Priolo et al., 2001).  The other Groups were similar for pH values and 
were on a higher plane of nutrition. 
 Lean L* values for the Groups were not different although the pH values of Group 1 were 
greater.  However, the differences for a* and b* showed no clear trend.  More than likely, the 
43 
 
differences in the a* and b* values were the result of differences in oxygenation rate related to 
inherent differences in the physiology of the steers in the project.  Mancini and Hunt (2005) 
noted in their review of color that factors such as the meat?s temperature, oxygen partial 
pressure, meat pH, and competition by other respiratory processes affect oxygen penetration into 
the muscle and oxymyoglobin thickness.  This could explain the differences between the Groups 
a* values at 24 h with some Groups possessing respiratory processes with lower oxygen needs 
than the other Groups because of lower postmortem metabolic rates.  The L* values for fat color 
were similar for Groups 2, 3, 4, and 5 with Group 6 having the highest L* value.  This could 
possibly be the result of increased fat accretion.  However, if this was the case, it would be 
expected that the other color values would change similarly as well.  This was not the case as fat 
a* values showed no differences among Groups.  Moreover, the b* values showed no trend 
among Groups or forage types, and within forage types showed there were no differences.  
Baublits et al. (2004) found that feeding soyhulls to cattle grazing on either fescue or 
orchardgrass did not change fat yellowness compared with cattle grazing fescue only.  The 
reason for the differences in the fat b* values is not known. Yang et al. (1992) showed that the 
carotenoids are responsible for the yellow fat color of forage-finished beef.  It could possibly be 
that the function of the maturity of the plants being grazed impacted the amount of carotenoids 
available to the animal.  This would then allow for increased carotenoids to be deposited in the 
adipose tissue thereby increasing fat b* values.   
Instrumental Color Characteristics 
 The L* values for steaks during simulated retail were lower for Group 1than the other 
Groups.  This was most likely caused by the higher 24 h pH value decreasing the amount of light 
scattering on the surface of the muscle (Norman et al., 2004).  This interaction of day x Group 
44 
 
was caused in part by Group 1 having a similar value on d 0 as on d 6 whereas the other Groups 
had a general decline in L* values from d 0 to d 6.  Rowe et al. (2009) noticed a decrease in L* 
values over 7 d of display while Braden et al. (2007) found no differences over 5 d of display.  
The a* values showed a decline from d 0 to d 6.  O?Sullivan et al. (2004) found that over 17 d of 
display, a* values decreased.  During that same time, O?Sullivan et al. (2004) found that 
metmyoglobin percent increased.  This is expected because of increased myoglobin oxidation 
caused by the inability of the muscle to carry out metmyoglobin reduction mechanisms (Lanari et 
al., 1996).  Moreover, competition of the mitochondria for oxygen and ultimately the use of 
NADH causes a depletion of NADH which is needed for the reduction of metmyoglobin 
(Mancini and Hunt, 2005).  This loss in the reduction properties then causes an increase in the 
amounts of metmyoglobin, resulting in a brown color on the surface of the muscle and 
decreasing a* values (Mancini and Hunt, 2005).  Likewise, the decrease in b* values is most 
likely caused by the same mechanisms. 
 The Group x day interaction for hue angle was caused in part because of Group 1 had 
similar values on d 0 and d 6, whereas the other Groups had a general increase in hue angle 
values.  Hue angle is a measure of the trueness of red color with lower values indicating a more 
true red.  The increase in values is caused by the decrease of oxymyoglobin and an increase in 
metmyoglobin.  Moreover, since hue angle is calculated using a* and b* values, a change in 
those values would elicit changes in hue angle (Yancey and Kropf, 2008).   Stivarius et al. (2002) 
found that ground beef over 7 d in display, had increased hue angle values.   The Group x day 
interaction for Chroma was caused in part again by Group 1 having a higher value on d 0 but was 
similar in value to other Groups on d 6.  Chroma is a measure of vividness with larger values 
indicating a more vivid color.  The Chroma values had a generalized decrease in value over the 7 
45 
 
d of display.  Like hue angle, Chroma is measured by calculating the a* and b* values (Yancey 
and Kropf, 2008).  Changes in either one or both of those values would change the value of 
Chroma (Yancey and Kropf, 2008).  As can be seen by the a* and b* values, the increase in hue 
angle signifying a loss in true redness and a decrease in Chroma signifying a loss in vividness is 
mimicked by the a* and b* values.  With the exception of Group 1, the values for the 630/580 
nm ratio remained similar which indicates that the oxidation of oxymyoglobin to metmyoglobin 
was low.  However, it was not low enough to keep the other color measures from deteriorating.  
Stivarius et al. (2002) found that ground beef over 7 d in display had decreased 630/580 nm 
ratio.  However, in the current study, the values remained similar.  
Cook loss, Warner-Bratzler Shear Force and TBARS 
 The cook loss results do not show any apparent trends.  French et al. (2001) found results 
similar to those of the present study, with Groups 2 and 6 had different amounts of marbling, but 
cook loss values were similar among the Groups.  Kerth et al. (2007) found that cattle with 
similar amounts of marbling had similar cook loss values.  Moreover, Group 1 had the highest 
pH among the Groups but had the greatest numerical cook loss for each aging period.  Sawyer et 
al. (2008) found that dark-cutting beef (high pH) had lower cook loss than that of the normal pH 
meat.  The current study contradicts this.  Although Group 1 would not have been considered 
dark-cutting, it would still be considered to be above normal.  Shanks et al. (2002) postulated 
that during long aging periods (14 d or more), muscle loses its inherent ability to hold moisture.   
However, in the current study, the lack of a trend among the treatment Groups suggests that 
inherent differences between animals and muscles are likely the cause of differences between 
Groups.  Seideman et al. (1982) found, using loins from grain-fed and forage-fed cattle with two 
different storage times (7 d and 21d), no differences between production system (forage vs. 
46 
 
grain) and storage time on cook loss.  The storage time results are in agreement with the current 
study, with all of the Groups having at least two similar values within aging periods. 
 The results for Warner-Bratzler shear force show a trend of lower shear values for 
increased time.  Although the 21-d and DIS steaks were the same age, the DIS steaks were 
displayed in a retail display case for 7 d.  The temperatures in the display case were higher (4o C 
vs. 2o C) than the temperatures in the cooler where the 21-d steaks were kept.  It is possible that 
this increase in average temperatures increased the amount of proteolysis occurring in the 
muscle, which caused increased tenderization compared with the other Groups.  Koohmaraie 
(1992) found that increased temperatures increased the amount of proteolysis of proteins within 
purified myofibrils.  Although Koohmaraie compared 25o C and 5o C for the temperature effects 
on proteolysis, warmer temperatures would still increase proteolysis, just to a lesser extent than 
what Koohmarie?s results indicated.  With the exception of Group 1, all of the DIS steaks had 
significantly lower shear values than their 14-d counterparts.  Moreover, with the exception of 
Group 5, mean numerical values decreased from 14-d steaks to DIS steaks.  Seideman et al. 
(1982) found that increased storage time (7 d vs. 21 d) decreased shear values.  May et al. (1992) 
found a moderately negative relationship with days fed and shear values, indicating that, as days 
on feed increased, shear values decreased.  However, in the current study, Group 1 had similar 
values to Group 5 and 6 for all analyses, which would indicate that in this study, days fed had 
little impact on shear values. 
 The results from the TBARS analyses are much like the shear force and cook loss 
analyses had no trend present among the Groups, although Groups 3, 4, 5, and 6 had lower 
TBARS values for DIS steaks than Groups 1 and 2.  The reason for the 21-d values being greater 
than the DIS values in some cases is not known.   The relative low values indicate that even 
47 
 
though there were moderate to high levels of polyunsaturated fatty acids, which are highly prone 
to oxidation, the antioxidant status of the muscle was able to keep fatty acid oxidation low.  
Mercier et al. (2004) concluded that pasture-finishing has an important effect on the antioxidant 
status, such as vitamin E and antioxidant enzymes compared with animals on a mixed-grain diet.  
Although the current study did not compare muscles from grain-fed and forage-fed cattle, the 
antioxidant status of the muscle would still be increased.  Likewise, Arnold et al. (1993) found 
that feeding vitamin E to grain-fed cattle decreased TBARS values compared with 
unsupplemented controls.  Furthermore, Arnold et al. (1993) found that, as time in display 
increased, TBARS values for the unsupplemented controls increased, whereas the vitamin E- 
supplemented controls remained similar across days of display.  This could be the reason for the 
differences in the results of the current study.  It could be possible that the different steaks 
expended the amount of antioxidants at differing rates causing differences in the amount of 
oxidation.    
Sensory Evaluation 
 The results for initial and sustained juiciness showed a Group x aging period interaction.  
It should be noted that, while the interaction occurred, there were not large differences within 
each Group.  Each Group had at least two aging periods that were similar in value, which 
indicates that the amount of juiciness was not impacted greatly by the different aging periods.  
Xiong et al. (1996) and Sapp et al. (1999) both found no differences among treatments for aging 
periods and juiciness.  However, French et al. (2001) found aging time to have an impact on 
juiciness scores of beef.  However, even though they found differences, the differing aging 
periods impacted juiciness differently, which suggest that another variable might have a larger 
impact than aging period.  The 14-d aging period for initial and sustained juiciness indicates a 
48 
 
trend that as days on forage increased, the amount of juiciness increased.   Conversely, May et al. 
(1992) and Schaake et al. (1993) both found, using a concentrate diet with differing feeding 
times, that as days on feed increased, there were no differences between the first and last groups.  
Furthermore, their data did not show any trends among the groups for increased or decreased 
juiciness as days on feed increased. 
 The initial and sustained tenderness results are much like the results for initial and 
sustained juiciness.  Each of the Groups had at least two values for the aging period being 
similar.  Furthermore, increased days of grazing did not have an apparent affect on perceived 
tenderness.  Likewise, Schaake et al. (1993) found no differences in tenderness between the first 
and last Group of cattle fed for different periods of times.  However, May et al. (1992) found that 
after 56 d of feeding a high-concentrate diet, sensory tenderness values were greater than those 
cattle fed for fewer days.  Moreover, after 84 d, May et al. (1992) found there to be no 
improvement in tenderness ratings.  Comparisons of forage-fed and grain-fed cattle often result 
in the grain-fed beef having better tenderness ratings.  However, the literature does not offer any 
results for the comparison of days of grazing in a serial harvest scenario.  This makes 
extrapolation of the results difficult.  However, according to the present data, Group 1 had 
similar values for initial and sustained tenderness as Group 6, which indicates that improvements 
in tenderness would be difficult to achieve for forage-fed beef models in the current study. 
 The results from the beef flavor intensity ratings indicate that improvements in beef 
flavor are low.  Although Groups 5 and 6 had higher ratings for the 14-d aging period and Group 
6 had higher ratings than Group 1 for the 21-d and DIS aging period, improvements were still 
low.  It would be expected that with the great difference in intramuscular fat content that Group 6 
would have much higher scores than Group 1.  The data suggest that there may be more variables 
49 
 
than just fat content impacting beef flavor, which is in agreement with Calkins and Hodgen 
(2007).  They noted that many compounds contributing to the flavor of beef are water-soluble, 
which would explain at least in part, why the fatty acid content had little effect on beef flavor. 
 The results for off-flavor intensity show that the amount of off-flavor was low.  However, 
like the other sensory results, with the exception of Groups 3 and 4, all the other Groups have at 
least 2 aging periods with similar values.  The reason for the 21-d aging period having a higher 
value than the DIS aging period is unknown.  DIS steaks were expected to have a greater value 
than the others because of the 7 d in display.  However, this was not the case. 
 There were no differences in bloody, livery, salty, bitter and metallic off-flavors.  This 
may be because the steaks were not enhanced.  Furthermore, strip loins have not been implicated 
for having off flavors such as livery and metallic.  The appearance of rancid and other off-flavors 
are likely that of oxidation.  Greene and Cumuze (1982) found a correlation between TBARS 
values and rancid taste in beef, which would indicate that as oxidation increased, the amount and 
appearance of rancid off-flavors increased.  Furthermore, Rhee and Myers (2003) found a high 
positive correlation with TBARS values and cardboard aromatics in goat meat.   The appearance 
of grassy off-flavors was expected because the cattle were fed forages, which would cause an 
increase in the polyunsaturated fatty acids leading to the increased incidence of grassy off flavors 
(Priolo et al., 2001). 
Fiber Types 
 Within each respective Group, all fibers had different mean areas, with Type Ia having 
the smallest area and Type IIb having the largest.  The Type Ia fibers showed a lack of 
significant growth after Group 3 indicating that the growth potential for these fiber types were 
realized with the plane of nutrition given.  Johnston et al. (1975) found cattle fed for 153 d had 
50 
 
larger Type IIa and IIb area than cattle fed for 233 d, although they were not significantly larger.   
Lefaucheur and Gerrard (1998) stated that genetic factors between breeds can influence fiber 
type composition.  The breed crosses used in this study could be the reason for the disparity in 
fiber type size and distribution.  Greenwood et al. (2009) found that nutritionally restricted cattle 
had a loss in muscle mass compared with the unrestricted Group.  However, this cannot explain 
the discrepancy within the Groups of the current study because of increased LM areas and BW.  
Vestergaard et al. (2000a) found that fiber areas were similar for the Type IIb fibers for the 460-
kg extensive production Group compared with the 360-kg extensive production group.  The lack 
of difference show that when using different groups of animals for different harvest times, 
inherent differences between animals can increase variability.   
 The percent of the fiber types were not dramatically different among the Groups, most 
likely because of similar planes of nutrition among groups during the project.   Although the 
cattle grazed forages and the quality of the forages can be variable during different times of the 
year, it would still be expected that the plane of nutrition would be similar.  Greenwood et al. 
(2009) found that nutritionally restricted cattle had an increase in the amounts of Type Ia 
oxidative fiber types, indicating that the plane of nutrition can shift fiber types.  Moreover, they 
found that when the nutritionally restricted cattle were given adequate feed, the fiber types 
shifted to be more like that of the conventionally fed cattle, which would indicate that the 
animals metabolic needs dictate the type of metabolism needed to sustain life.  Lefaucheur and 
Gerrard (1998) noted that the general idea of the shift of fiber types was from Type IIb 
?IIx?IIa? when activity level increased.  The animals from the present study had a high 
activity level, which would increase the Type Ia and IIa fibers.  Moreover, this would keep the 
oxidative fiber types more prevalent compared with cattle being finished using a concentrate 
51 
 
diet.  Vestergaard et al. (2000a) found that the extensive-production (pasture) cattle had greater 
percentages of Type Ia fibers than intensive-production (concentrate diet) cattle.  Moreover, 
Vestergaard et al. (2000a) found that the extensive cattle had greater vascularization compared to 
the intensive Group indicating greater blood flow for the oxidative fiber types. 
Fatty Acid Profiles 
 The lack of differences in the fatty acid profiles indicate that forage type and days on 
forage had little or no impact on the types of fatty acids deposited.  Fincham et al. (2009) found 
using four biopsy periods over 140 d increased amounts of elaidic acid (18:1 t-9) after the first (d 
28) sampling period, decreased saturated fatty acids and increased monounsaturated fatty acids 
after 112 d from cattle fed a mixture of timothy hay, soybean meal and soybean hulls (Neel et al., 
2007).  This would be in partial agreement with the results of the current study.  Moreover, in the 
Fincham study, the cattle grazed multiple paddocks utilizing combinations of triticale/ annual 
ryegrass, alfalfa/ orchardgrass, and a cool-season / legume mixture.  The lack of differences 
across time would indicate that forage type did not have a large impact on the fatty acid profile 
similar to the results of the current study.   Noci et al. (2005) found that as days on forage 
increased, total PUFA increased as well as certain fatty acids such as eladic acid, 
docosopentonoic acid, and linolenic acid, to name a few.  However, it must be noted that in the 
Noci et al. (2005) study, the animals were all harvested at the same age endpoint.  Furthermore, 
when the cattle were not grazing, they were fed a silage and concentrate diet.  This would impact 
the fatty acid profile and still make extrapolation to the current study difficult.   
 
 
 
52 
 
Conclusions 
 
 Improvements in tenderness from increased days of grazing may be difficult to achieve 
using forage-fed beef growth models.  The lack of improvements in tenderness indicate that 
harvesting at a younger age or fewer days of grazing may be a possibility for increasing animal 
turnover which has been an issue for forage-fed beef.  Muscle fiber growth characteristics and 
their impact on quality characteristics have still not been elucidated. The forages used in this 
study indicate that it is possible to change forages without having great impact on palatability or 
fatty acid profiles.  Further research into forage types and quality characteristics are needed.  
 
 
 
 
53 
 
Chapter IV 
 
Sensory, Quality, and Instrumental Color Characteristics of Striploins from Forage-Finished and  
 
Grain-Finished Beef 
Abstract 
 
 Striploins from forage-finished (n=17) and grain-finished (n=18) cattle were procured to 
compare quality, sensory and instrumental color characteristics.  Loins from forage-finished 
cattle were procured from steers that grazed ryegrass through the spring and bermudagrass and 
fescue through the summer.  Steers were harvested in late August.  Striploins were removed from 
the carcasses 24 h postmortem, vacuum-packaged and stored in the dark at 2o C for a total of 21 
days.  Loins from grain-finished cattle were procured from a commercial Midwest processor and 
were of USDA Select quality.  Loins were transported to the Lambert-Powell Meats Lab and 
stored in dark at 2o C until loins were 21 d of age from time of harvest.  Histochemical samples 
were obtained from loins of forage-finished cattle 24 h postmortem, and samples from loins of 
grain-finished cattle were obtained 96 h postmortem.  Samples were frozen in isopentane chilled 
in liquid nitrogen and stored at -80o C until time of analyses.  After completion of aging, loins 
were cut into 2.54 cm-thick steaks and analyzed for either fresh shear force, sensory, 
thiobarbituric acid reactive substances (TBARS), fatty acid analyses or display shear force, 
sensory and TBARS.  Fresh steaks were individually vacuum-packaged and frozen until time of 
analyses.  Display steaks were placed on a Styrofoam tray with a polyabsorbent pad, 
overwrapped with polyvinyl chloride film and placed in a display case for instrumental color 
54 
 
characteristics during simulated retail display.  Upon completion of display, steaks were vacuum 
packaged and frozen until time of analyses.  Shear force, cook loss, sensory evaluation and 
TBARS data were analyzed using generalized linear models with the fixed effects of feed type 
and aging period (fresh or display).  Instrumental color data were analyzed using mixed model 
procedures with feed type, and day as fixed effects.  Results indicate that loins from grain-
finished cattle had greater (P < 0.05) L*, b*, hue angle, and Chroma values during display.  
Grain-finished cattle had muscles with greater (P < 0.05) fiber sizes while forage-finished cattle 
had muscles with greater (P < 0.05) percentages of Type Ia fiber types.  Meat from forage-
finished cattle had higher (P < 0.05) juiciness ratings whereas meat from grain-finished cattle 
had greater (P < 0.05) tenderness ratings for sensory evaluation.  Warner-Bratzler shear force 
values were less (P < 0.05) for steaks from grain-finished cattle than forage-finished cattle.  
Grain-finished cattle had LM with greater (P < 0.05) percentages of saturated fatty acids whereas 
LM from forage-finished cattle had lower (P < 0.05) n6:n3 ratios.  Steaks from grain-finished 
cattle had significantly (P < 0.05) lower shear values, greater fiber size and higher sensory 
tenderness ratings.  Steaks from forage-finished cattle had increased (P < 0.05) sensory juiciness 
and lower (P < 0.05) n6:n3 ratios. 
Introduction 
 
 Grass- or forage-based systems have gained in popularity over the past ten years because 
of an increase in input costs (Brown et al., 2007), human health (University of California, 2002), 
animal care (Vestergaard et al., 2000a) and environmental (USDA-ERS, 2002) concerns.  
However, forage-based beef production systems generally cause decreased rates of growth 
(French et al., 2001; Bidner et al., 1986; Bidner et al., 1981 ), more yellow fat color (Kerth et al., 
2007; Realini et al., 2004; ), and a grassy flavor (Baublits et al., 2006).  Tenderness remain an 
55 
 
issue and Vestergaard et al. (2000b), Mitchell et al. (1991) and Bowling et al. (1977) have shown 
that  grain-fed cattle produced more tender steaks.  However, Kerth et al. (2007), Mandell et al. 
(1998), and Bidner et al. (1986) found no differences in tenderness of steaks between grain- and 
forage-finished cattle. 
 The fatty acid profile of beef has been a topic of discussion for several years, focusing on 
the n-6:n-3 fatty acid ratio.  Carroll and Roth (2002) reviewed the role of omega-3 fatty acids and 
concluded that there is considerable evidence for the use of omega-3 fatty acids for the 
prevention of heart disease.    Several authors have shown that forage-finished beef has a lower 
n-6:n-3 fatty acid ratio (Duckett et al., 2009; Nuernberg et al., 2005; Enser et al., 1998), which 
may help in the prevention and management of diseases such as cardiovascular disease, auto 
immune diseases and diabetes, and have suggested a ratio of 4:1 or less (Simopoulos, 2002). 
 Grain-based finishing systems have been used extensively over the past 40 years to 
produce animals with high rate of growth, and highly marbled cuts of meat.  Therefore, the 
objectives of this study was to: 1) compare forage-finished cattle with conventional grain-
finished cattle for quality, sensory and instrumental color characteristics and 2) compare non-
displayed steaks to displayed steaks on sensory and quality characteristics. 
Materials and Methods 
 
Muscles and Sample Processing 
 A total of 35 striploins from forage-finished and grain-finished beef carcasses were 
obtained from the Lambert-Powell Meats Laboratory and a major commercial meat processing 
facility, respectively.  Striploins from forage-finished cattle (n=17) were obtained from the 
Lambert-Powell Meats Laboratory from cattle that had grazed forages.  Forage-finished cattle 
were placed on ryegrass, rye and oats in late fall at the Wiregrass Research and Extension Center 
56 
 
in Headland, AL and allowed to graze until forages could no longer support the animals growth.  
At that time, animals were transported to the Stan Wilson Beef Teaching Unit in Auburn, AL and 
placed on a predominantly fescue and bermudagrass pasture.  Cattle grazed from May to late 
August with ab libitum access to water, vitamin and mineral.  Cattle were then transported to the 
USDA inspected Lambert-Powell Meats Laboratory in Auburn, AL for humane harvest.  
Twenty-four hours postmortem, striploins from the left side of the carcasses were removed, 
vacuum-packaged and stored in the dark for a total of 21 d from time of harvest. 
 Striploins from grain-finished cattle (n=18) were obtained from a major meat processing 
facility.  Striploins were obtained from the same day of production at random and were USDA 
Select quality.  Loins were received at the Lambert-Powell Meats Laboratory and stored in the 
dark for a total of 21 d from time of harvest. 
 Histochemical fiber type samples were obtained from each striploin prior to aging.  The 
LM samples from the striploins of forage-finished cattle were obtained 24 h postmortem.  
However, samples from the striploins of the grain-finished cattle were obtained 96 h 
postmortem. 
 Upon completion of the aging period, loins were removed from their vacuum-packages 
and cut into 2.54-cm-thick steaks.  Steaks were analyzed for shear force, sensory, TBARS, fatty 
acid analyses, and display shear force, sensory and TBARS.  All steaks were individually 
vacuum-packaged and frozen until time of analyses. 
Instrumental Color and Retail Display 
Fresh (never frozen) steaks aged for 21 d from time of harvest were cut to 2.54-cm.thick 
and placed on Styrofoam trays with an absorbent pad, overwrapped with polyvinyl chloride 
(PVC) film then placed in a coffin-style retail display case at 4o C for 7 d with the light intensity 
57 
 
at 1,100 1x using Sylvania? Designer Cool White Plus bulbs (F40/DCWP).  Instrumental color 
characteristics were recorded on d 0 and 6 of retail display using a Hunter Miniscan XE Plus 
(Model 45/0-L, Hunter Associates Laboratory, Inc., Reston, VA, USA).  The CIE L*, a*, b* and 
reflectance values were determined from the average of two random readings from the surface of 
each steak using Illuminant D65 with a 10o standard observer and a 3.5 cm aperture.  Hue angle 
was calculated using tan-1(b*/a*), and saturation index was calculated by square root (a*2 + b*2).  
The 630/580 nm ratio was calculated by dividing the reflectance value at 630 nm by the 
reflectance value at 580 nm. 
Shear force, cook loss and sensory evaluation 
 Steaks were allowed to thaw at 2o C for 24 h prior to cooking.  Upon completion of 
thawing, steaks were cooked using the method of Kerth et al. (2003).  Steaks were cooked on 
clam-shell style grills for a constant time of 6.75 min to an average internal temperature of 71o C.  
Upon completion of cooking, steaks were cooled to 4o C.  Six 1.27-cm-thick round cores were 
then taken parallel to the fiber direction of each steak.  Cores were sheared once perpendicular to 
fiber direction using a Warner-Bratzler shear machine (Model 1955; G. R. Electric 
Manufacturing, Manhattan, KS). 
 Cook loss values were determined by weighing steaks prior to cooking.  After cooking, 
steaks were allowed to cool and then were reweighed.  Cook loss was calculated using the 
following formula. 
Fresh weight ? Cooked Weight 
_____________________________________________   X 100 
Fresh Weight 
 
 Sensory evaluation steaks were allowed to thaw at 2o C for 24 h prior to cooking.  Steaks 
were cooked by the same method described for shear force.  After cooking, steaks were cut into 
58 
 
1.3-cm X 1.3-cm X steak thickness cubes and placed in a warmer at 65o C for no longer than 20 
min. 
 Panelists were trained in accordance with AMSA (1995) guidelines.  Samples were 
assigned random numbers prior to serving.  Panelists were given unsalted crackers and water to 
cleanse their pallets between samples.  Two samples from each steak were evaluated by panelists 
in partitioned booths with red incandescent light.  Samples were evaluated for initial and 
sustained juiciness, initial and sustained tenderness, flavor intensity, and beef flavor on a scale of 
1 to 8, with 1 = extremely dry, dry, tough, tough, bland, and extreme off-flavor, and 8 = 
extremely juicy, juicy, tender, tender, intense, and no off-flavor, respectively.  When off-flavors 
were present, panelist identified the off-flavor as other, bloody, livery, metallic, rancid, grassy, 
bitter or salty.  Off-flavors are reported as the percentage of times that it was present within a 
sample.    
Fatty Acid Profiles 
 Fatty acid profiles were determined using the method of O?Fallon et al. (2007).  Briefly, 1 
g of muscle tissue was placed in 30 mL glass tube.  Then, 5.3 mL of MeOH, 0.7 mL of 10 N 
KOH in water, and 2 mg trinondecanoin (C:19:0; internal quantification standard) was added to 
the sample and then incubated for 90 min at 55o C in a water bath with a shaker attachment.  
Samples were then removed and allowed to cool in tap water to room temperature.  After 
cooling, 0.58 mL of 24 N H2SO4 was added to the sample and samples were then incubated in a 
shaker/water bath for 90 min at 55o C.  Samples were removed from water bath, placed in tap 
water and allowed to cool to room temperature.  After cooling, 3 mL of hexane was added to 
samples and then vortex-mixed for 5 min followed by centrifugation for 5 min at 1,500 x g.  The 
hexane layer was then removed, placed in vials and stored at -20o C until analyses. 
59 
 
 Fatty acid profiles were determined using an Agilent Technologies 6890N Network GC 
System using a 60m long, 0.25 mm inner diameter, 0.1 ?m film thickness DB-23 High 
Resolution Gas Chromatography column (Agilent Technologies, Santa Clara, CA, USA).  The 
GC was programmed for an oven temperature of 130o C for 1 min, 130-170o C at 6.5o C/ min, 
170-215o C at 2.75o C/ min, 215-230o C at 40o C/ min and had a constant temperature of 230o C 
for 3 min with a split ratio of 50:1.  The detector and injector temperature was set at 250o C. The 
injector was set at 1?L of sample with helium as the carrier gas with a flow rate of 1 mL/min.  
The fatty acid methyl ester (FAME) standards (Nu-Check Prep, Inc.) were run daily to identify 
retention times of FAME.  The FAME peaks were then integrated so that individual FAME 
could be identified.  
Histochemical fiber type analyses 
 Histochemical fiber type analyses were determined using the method of Solomon and 
Dunn (1988).  In brief, 24 h (forage-finished cattle) and 96 h (grain-finished cattle) postmortem, 
0.5 cm x 0.5 cm x 1.5 cm cubes were excised from the LM parallel to fiber direction and frozen 
in isopentane chilled in liquid nitrogen and then stored at -80o C.  Samples were mounted on cork 
board using freezing gel with fiber orientation perpendicular to the cork board.  Sections were 
then cut 10 ?m thick using a Microm HM 505 E microtome (Thermo Fisher Scientific, Waltham, 
MA, USA) and transferred to slides.  Slides were then stained and covered with a cover slip 
using glycerol mounting gel.  Fiber type determinations were determined using a Motic BA 300 
(Motic, Richmond, BC, Canada) microscope with a digital camera attachment.  A total of eight 
pictures were taken from each slide so that approximately 100 fibers were represented for 
analyses.   
60 
 
 Fibers were determined by mitochondrial amount and shade of cell.  Darkly shaded cells 
with large amounts of mitochondria were determined to be ?-red fibers.  Fibers that displayed 
moderately dark shading with moderate amounts of mitochondria were determined to be ?-red 
fibers and lightly shaded fibers with low amounts of mitochondria were determined to be ?-white 
fibers. 
 Fiber sizes were determined by calculating total area within the cell.  To obtain an 
accurate measurement, the microscope was calibrated using the certified calibration slide from 
Motic.  Measurements for area are presented as ?m2, and total number of fibers are presented as 
percentages of total fibers. 
Thiobarbituric Acid Reactive Substances 
 Thiobarbituric reactive substances (TBARS) were determined using the method of Wang 
et al. (2002).  Five grams of meat was minced and placed in a 50 mL centrifuge tube.  Then, 15 
mL of 7.5% TCA solution was added and samples were homogenized using a bullet blender 
(Bella Cucini Rocket Blender, Bella Cucina Artful Food, Inc., Montreal Canada) for 30 sec.  
Samples were centrifuged at 1,500 g for 10 min at 2o C using a Beckman Coulter Allegra X-15 R 
(Beckman Coulter, Inc., Brea, CA, USA) swinging bucket rotor followed by filtering through 
No. 4 Whatman paper (Whatman, plc, Kent, UK).  Three millileters of sample was placed in a 
16-mL glass tube in duplicate.  Then, 3 mL of 40 mM TBA was added to the sample and 
incubated at 40o C for 90 min.  Samples were then placed in cold water for 20 min and standards 
were prepared and incubated with the samples.  Samples were read using a spectrophotometer 
(Beckman Coulter DU 730, Beckman Coulter, Inc., Brea, CA, USA) at 532 nm.  Results are 
presented as equivalents of mg malondialdehyde / kg meat. 
61 
 
 Standards were made using a stock solution of tetraethoxypropane (TEP) at 1 mM/L.  
The stock solution was diluted to 0, 2, 4, 6, 8, 10, 20, and 30 ?M/mL.  A standard curve was then 
generated for each run and used for the samples on each respective run. 
Statistical Analyses 
 Data were analyzed using SAS 9.1 (SAS Institute, Inc., Cary, NC, USA).  Instrumental 
color data were analyzed using mixed model procedures with the fixed effects of feed type, and 
Day was analyzed as a repeated measure.  All other data were analyzed by ANOVA with the 
fixed effects of feed type and aging period.  Least squares means were generated and separated 
using pair-wise t-test when the model P-Value was significant (P < 0.05). 
Results 
Instrumental Color Characteristics 
 Results for instrumental color characteristics are presented in Table 14.  Steaks from 
grain-finished cattle had greater (P < 0.05) L* values on d 0 and d 6 of display than the steaks 
from forage-finished cattle.  There was also a day effect with L* values being greater (P < 0.05) 
on d 0 than on d 6 of display.  There was a day X feed type interaction for a* values because 
steaks from grain-finished cattle had greater (P < 0.05) a* values on d 0, but were similar (P > 
0.05) to steaks from forage-finished cattle on d 6 of display.  Steaks from grain-finished cattle 
had greater (P < 0.05) b* values on d 0 and d 6 of display.  There was also a day effect with b* 
values being greater (P < 0.05) on d 0 than d 6 of display. 
 There was a day x feed type interaction (P < 0.05) for hue angle because steaks from 
grain-finished cattle had a greater increase in value from d 0 to d 6 of display than steaks from 
forage-finished cattle.  Steaks from grain-finished cattle had greater (P < 0.05) Chroma values on 
both d 0 and d 6 of display.  Chroma values were greater (P < 0.05) d 0 than on d 6 of display.  
62 
 
There was a day x feed type interaction for 630/580 nm ratio because of steaks from forage-
finished cattle had a lower (P < 0.05) value than steaks from grain-finished cattle on d 0, but had 
a greater (P < 0.05) value than steaks from grain-finished cattle on d 6 of display. 
Fiber type area and percentages 
 Muscles from grain-finished cattle had larger (P < 0.05) average fiber areas than forage-
finished cattle (Table 15).  Likewise, Type IIb fibers were larger (P < 0.05) than Type IIa and 
Type Ia fibers, Type Ia fibers were smaller (P < 0.05) than Type IIa and Type IIb fibers, and 
Type IIa fibers were smaller (P < 0.05) than Type IIb fibers and larger (P < 0.05) than Type Ia 
fibers.  Muscle from grain-finished cattle had more (P < 0.05) Type IIa and IIb than Type Ia 
fibers.  Likewise, muscle from forage-finished cattle had more (P < 0.05) Type IIb and Ia fibers 
than Type IIa fibers.   
Sensory Evaluation, cook loss, shear force and TBARS 
 There were no feed type x aging period interactions (P > 0.05; Table 16) for sensory 
evaluation.  Steaks from forage-finished cattle had greater (P < 0.05) initial juiciness values than 
steaks from grain-finished cattle.  Moreover, the fresh steaks had greater (P < 0.05) initial 
juiciness values than the display steaks.  Steaks from forage-finished cattle had greater (P < 0.05) 
sustained juiciness values than steaks from grain-finished cattle and fresh steaks had greater (P < 
0.05) sustained juiciness ratings than the display steaks. 
 Steaks from grain-finished cattle had greater (P < 0.05) ratings for both initial and 
sustained tenderness.  However, there were no differences (P > 0.05) for aging periods.  Beef 
flavor intensity values were similar (P > 0.05) for steaks from grain-finished and forage-finished 
cattle.  However, fresh steaks had greater (P < 0.05) beef flavor intensity ratings than display 
steaks.  Steaks from grain-finished cattle had lower (P < 0.05) off-flavor ratings than steaks from 
63 
 
forage-finished cattle.  Moreover, fresh steaks had lower (P < 0.05) off-flavor ratings than the 
display steaks. 
Cook loss values were similar (P > 0.05) between steaks from grain-finished and forage-
finished cattle as well as for fresh and display steaks.  Grain-finished cattle had lower (P < 0.05) 
shear force values than forage-finished cattle for both age periods. 
 Steaks from forage-finished cattle had greater (P < 0.05; Table 17) mean ratings for other 
off-flavors.  Moreover, fresh steaks had lower (P < 0.05) other off-flavor ratings than display 
steaks.  Other off-flavors are those that are not identified in the descriptors and were identified 
by panelist as fishy or sour.  Steaks from forage-finished cattle had a greater (P < 0.05) rancid 
rating for fresh steaks than fresh grain-finished steaks.  However, display steaks from forage-
finished and grain-finished cattle had similar (P > 0.05) rancid ratings.  Steaks from forage-
finished and grain-finished cattle were not different (P > 0.05) with either aging period for 
bloody, bitter, grassy, livery, salty, and metallic off-flavors .   
 Steaks from grain-finished and forage-finished had similar (P > 0.05) TBARS values for 
fresh steaks; however, steaks from grain-finished cattle had greater (P < 0.05) amounts of 
malondialdehyde for the display aging period than display steaks from forage-finished cattle. 
Fatty Acid Profiles 
 Results for fatty acid profiles for mg / g meat and percentage of total fatty acids are 
presented in Tables 18 and 19, respectively.  Steaks from grain-finished cattle had greater (P < 
0.05) concentrations of the fatty acids 12:0, 15:0, 16:0, 16:1, 17:0, 17:1, 18:0, 18:1 n9 t, 18:2 n6, 
20:3 n6, 20:4, and 22:4 than steaks from forage-finished cattle.  Likewise, steaks from forage-
finished cattle had greater (P < 0.05) concentrations of 18:3 n3, 20:3 n3, 22:0, and 22:5 than 
steaks from grain-finished cattle.  Steaks from grain-finished cattle had greater (P < 0.05) 
64 
 
concentrations of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty 
acids.  However, this was expected because of the fact that the grain-finished cattle most likely 
had greater amounts of fat in the muscle. 
 Meat from grain-finished cattle had higher (P < 0.05) percentages of the fatty acids 14:0, 
15:0, 16:0, 17:0, 18:1 n9 t, and 22:4 than meat from forage-finished cattle.  However, steaks 
from forage-finished cattle had greater (P < 0.05) percentages of the fatty acids 13:1, 15:1, 16:1 t, 
16:1, 18:2 n6t, 18:3 n3, 20:3 n3, 22:0, and 22:5 than steaks from grain finished cattle.  Meat from 
grain-finished cattle had greater (P < 0.05) percentages of saturated fatty acids and also had a 
greater (P < 0.05) n6:n3 ratio than meat from forage-finished cattle. 
Discussion 
 
Instrumental Color Characteristics 
 The L* values for the steaks from grain-finished cattle were greater than the steaks from 
forage-finished cattle for both d 0 and d 6 of display.  Nuernberg et al. (2005) and Realini et al. 
(2004) found that steaks from grain-finished cattle had higher L* values than steaks from their 
forage-finished counterparts.  Baublits et al. (2004) found that supplementation of soyhulls to 
forage-finished cattle increased L* values in steaks compared with the unsupplemented control.  
Conversely, French et al. (2001) found no differences between steaks from forage-finished and 
grain-finished cattle for L* values.   The day x feed interaction for a* values resulted from steaks 
from grain-finished cattle had greater values on d 0 but similar values on d 6 of display 
compared with steaks from forage-finished cattle.    Steaks from forage-finished and grain-
finished cattle had similar a* values on d 6 of display, most likely because of the oxidation of the 
myoglobin molecule.  Braden et al. (2007) found that a* values decreased over time while beef 
steaks were in display.   
65 
 
 The day x feed interaction for hue angle was due to a larger increase in value from d 0 to 
d 6 of display for the steaks from grain-finished cattle compared to the steaks from forage-
finished cattle.  The hue angle is a measure of trueness of red color, with lower values indicating 
a more true value.  The increase in hue angle was most likely caused by an increase in oxidation 
of the myoglobin, resulting in a brown color on the surface of the muscle.  Moreover, since hue 
angle is calculated using a* and b* values, a change in those values would elicit changes in hue 
angle (Yancey and Kropf, 2008).  Braden et al. (2007) found an increase in hue angles over 5 d 
of display using inside beef rounds.  Koger et al. (2010) found over 7 d of display that TBARS 
values increased while a* values decreased, which would indicate increased myoglobin oxidation 
causing a loss of redness and ultimately a higher hue angle value.  Chroma values were higher 
for steaks from grain-finished cattle on both d 0 and d 6 of display.  Chroma is a measure of 
vividness with larger numbers indicating a more vivid color.  The 630/580 nm ratio showed an 
interaction of day X feed.  Although both values decreased significantly over the 7 d of display, 
steaks from forage-finished cattle had greater values on d 6 of display.  Steaks from grain-
finished cattle had a higher 630/580 nm ratio on d 0, likely as the result of increased oxygen 
penetration followed by an increase in oxymyoglobin to metmyoglobin.  The data shows that 
there is a roughly 0.6% difference in the d 0 values and 0.5% in the d 6 values.  It appears that 
the steaks from grain-finished cattle had a slightly greater affinity for oxymyoglobin on d 0, and 
that the steaks from forage-finished cattle preserved myoglobin better through display from 
increased antioxidant status.  Mercier et al. (2004) concluded that pasture-finishing has an 
important effect on the antioxidant status, such as vitamin E and antioxidant enzymes compared 
with animals on a mixed-grain diet, which could explain why the steaks from forage-finished 
cattle had greater 630/580 nm ratios on d 6. 
66 
 
Fiber Types 
 Type IIb fibers had the largest area while the Type Ia fibers had the smallest, which was 
expected because literature reports that the Type IIb fibers are the largest followed by Type IIa 
and Type Ia (Klont et al., 1998).  Moreover, muscle from grain-finished cattle had greater fiber 
areas than muscle from forage-finished cattle, which would be expected because of the higher 
plane of nutrition that the grain-finished cattle experienced compared with the forage-finished 
cattle.  Greenwood et al. (2009) found that an increased plane of nutrition resulted in larger 
muscle fiber areas.  Conversely, Vestergaard et al. (2000a) found no differences between 
production systems (intensive vs. extensive) for LM fiber area.  However, Vestergaard used bulls 
instead of steers which could have potentially increased growth of the fibers compared with 
steers. 
 Fiber percentage showed a fiber type x feed interaction due to percentages of Type IIa 
and Type IIb fibers were similar for muscles from grain-finished cattle, whereas Type IIb and 
Type IIa fibers were different for muscles from forage-finished cattle.  The decrease in the 
amounts of Type Ia fibers for muscles from grain-finished cattle compared with the Type IIa and 
Type IIb fibers is expected because of decreased physical activity and a higher plane of nutrition.  
Likewise, the increase in Type Ia fibers compared with the Type IIa fibers is expected because 
the forage-finished cattle had increased physical activity from grazing large expanses.  
Greenwood et al. (2009) found that nutrition-restricted cattle had an increase in the percentages 
of oxidative Type Ia fibers.  Likewise, Vestergaard et al. (2000a) found an increase in the 
amount of Type Ia fibers for cattle raised on pasture compared with cattle fed a concentrate 
ration in a small pen.  Moreover, as activity increases, the amount of oxidative fiber types will 
increase; likewise, as activity decreases the amount of glycolytic fiber types will increase 
67 
 
(Lefaucheur and Gerrard, 1998).  This explains why the grain-finished cattle had a lower 
percentage of Type Ia fibers compared to forage-finished cattle. 
Sensory Evaluation, Cook Loss, Shear Force and TBARS 
 Initial and sustained juiciness ratings were greater for steaks from forage-finished cattle.  
Juiciness decreased for display steaks compared with fresh steaks.  French et al. (2001) found 
that juiciness scores increased with aging time.  Conversely, Jennings et al. (1978) found no 
differences in juiciness using two aging periods (10 or 20 d).  The literature is inconclusive for 
sensory panel juiciness with regards to diet with Bruce et al. (2004) found that steaks from 
forage-finished cattle were juicier, Sitz et al. (2005) found that steaks from grain-finished cattle 
were juicer, and some authors found no differences between steaks from forage- and grain-fed 
cattle (Mitchell et al., 1991; Purchas and Davies, 1974; Camfield et al., 1997). 
Initial and sustained tenderness ratings were greater for steaks from grain-finished cattle 
for both aging periods than steaks from forage-finished cattle.  The literature is inconclusive for 
tenderness.  Some authors finding no differences between steaks from forage- and grain-finished 
cattle (Bidner et al., 1986; Schaake et al., 1993; Reagan et al., 1977), some authors reported 
steaks from grain-finished cattle more tender (Mitchell et al., 1991; Harrison et al., 1978; 
Bowling et al., 1977) and some found steaks from forage-finished cattle more tender (Bruce et 
al., 2004).  It could be postulated that grain-finished cattle would have greater amounts of fat, 
which would cause increased salivation and lubrication between the teeth.  Jennings et al. (1978) 
found that steaks with higher marbling were rated more tender than steaks with lower amounts of 
marbling.  Killinger et al. (2004) also found using paired loins with similar shear force values but 
differing degrees of marbling, that the higher marbled steaks were rated as more tender than the 
lower marbled steaks by panelist. 
68 
 
 Beef flavor intensity was similar for steaks from both grain-finished and forage-finished 
cattle.  However, beef flavor intensity ratings were lower for display steaks compared with the 
fresh steaks.  The literature is inconclusive for flavor intensity of the beef.  Some authors 
reported no differences between steaks from forage- and grain-fed cattle (Schaake et al., 1993; 
Bruce et al., 2004; Bowling et al., 1977), some reported steaks from grain-finished cattle higher 
rated (Mitchell et al., 1991; Purchas and Davies; 1974; Camfield et al., 1997), and other found 
steaks from forage-finished cattle with higher ratings (Reagan et al., 1977).  Off-flavor intensity 
ratings were higher for steaks from forage-finished cattle for both fresh and display steaks.  Rhee 
and Myers (2003) found a positive correlation with TBARS and cardboard-like flavor, which 
could explain why beef flavor scores decreased from the fresh steaks to the display steaks.  The 
increase in off-flavors would likely dilute the beef flavor of the steaks causing lower scores 
while increasing the off-flavor scores. 
The appearance of the other off-flavors was the result of the 7 d of display.  This was 
likely caused by the oxidation of both proteins and fatty acids.  The oxidation could have created 
intermediate compounds that, when heated, reacted to give off flavors such as fishy and sour.  
Moreover, higher values of rancid flavors occurring in the display steaks than fresh steaks 
indicates increased oxidation, which has been documented (Greene and Cumuze, 1982).  More 
than likely the other off-flavors were the result of this increased oxidation.   
The increased TBARS value for the display steaks from grain-fed cattle compared with 
the display steaks from forage-finished cattle was expected.  Yang et al. (2002) have reported 
that feeding forages increased the amount of the precursor to vitamin E (?-tocopherol) in the 
muscle which serves as an antioxidant compared with grain-fed cattle.  This antioxidant capacity 
would potentially decrease fatty acid oxidation, although myoglobin oxidation might still 
69 
 
proceed.  Gatellier et al. (2005) found that steaks from pasture-fed cattle had lower TBARS 
values compared with steaks from concentrate-finished cattle.  Mercier et al. (2004) concluded 
that pasture-finishing has a greater effect on the antioxidant status, such as vitamin E and 
antioxidant enzymes than animals on a mixed-grain diet.  Vitamin E can be an effective 
antioxidant for enhancing both color and lipid stability (Faustman et al., 1998). 
The similarity of cook loss values between steaks from grain- and forage-finished cattle 
was unexpected.  The literature is inconclusive.  Some authors found no differences between 
steaks from grain- and forage-finished cattle (Brown et al., 2007; Camfield et al., 1997; Bowling 
et al., 1977), some reported steaks from grain-finished cattle with higher cook loss (Bruce et al., 
2004) and others found steaks from forage-finished cattle with higher cook loss (Brown et al., 
2007). 
The lower shear values for grain-finished cattle were expected because of increased fat 
accretion and growth rate.  The literature is inconclusive as some authors reported no differences 
(Schaake et al., 1993; Bruce et al., 2004; Sitz et al., 2005) and some reported grain-finished cattle 
with lower shear values (Leander et al., 1978; Bowling et al., 1977; Brown et al., 2007).  
However, no studies were found in which steaks from forage-finished cattle had lower shear 
values than steaks from grain-finished cattle.   
Fatty Acid Profiles 
 Steaks from grain-finished cattle had greater amounts of total fatty acids within the 
samples, resulting in greater amounts of most of the major fatty acids.  This is expected because 
of increased fat content in the muscle.  The steaks from forage-finished cattle did however have 
greater amounts of the omega-3 fatty acids, which was expected because forages have been well 
70 
 
documented to increase the amounts of these fatty acids in the muscle (French et al., 2000; 
Realini et al., 2004; Steen et al., 2003). 
 Similar to the amounts of fatty acids, steaks from grain-finished cattle had greater 
percentages of the saturated fatty acids whereas the steaks from forage-finished cattle had greater 
percentages of the omega-3 fatty acids.  However, Yang et al. (2002), Nuernberg et al. (2005) 
and Realini et al. (2004) found no differences between steaks from forage-finished and grain-
finished cattle for saturated fatty acid percentages whereas French et al. (2000) found that steaks 
from grain-finished cattle had greater amounts of saturated fatty acids.  Moreover, steaks from 
grain-finished beef had a greater n6:n3 fatty acid ratio than steaks from forage-finished cattle.  It 
has been well documented that steaks from forage-finished cattle have lower n6:n3 ratios 
(Nuernberg et al., 2005; Steen et al., 2003; French et al., 2000). 
Conclusions 
 
 Steaks from grain-finished cattle had greater quality characteristics than steaks from 
forage-finished beef.  However, improvements in the fatty acid profiles of the forage-finished 
beef indicate that it may be a healthy option for consumers desiring foods with high amounts of 
n-3 fatty acids.  Off-flavor remains an issue with forage-finished beef.  Further research is 
needed in the area of flavor chemistry of forage-finished beef to elucidate the differing 
components responsible for the characteristic forage-finished beef flavor.  
71 
 
Chapter V 
 
Implications and Conclusions 
 
 Results from the first study indicate that increasing the number of days on forage is 
necessary to improve carcass characteristics with regards to BW and finish.  However, sensory 
and quality data show inconclusive results for the amount of time needed on forage.  Moreover, 
the lack of differences in fatty acid profiles suggests that ryegrass and crabgrass could possibly 
be used to maintain similar quality and sensory characteristics as well as fatty acid 
characteristics. 
 Results from the second study indicate that muscles from grain-finished cattle have larger 
fiber sizes, most likely from increased planes of nutrition.  Moreover, steaks from grain-finished 
cattle were more tender than the steaks from forage-finished cattle.  However, the steaks from 
forage-finished cattle were rated juicier than the steaks from grain-finished cattle.  The fatty acid 
profiles indicate that the steaks from grain-finished cattle had greater amounts of saturated fatty 
acids and larger n6:n3 ratio whereas the steaks from forage-finished cattle had greater amounts 
of the omega 3 fatty acids present. 
 Results from both studies indicate that the large scale production of forage-finished beef 
can produce beef of similar quality as conventional grain-fed beef.  However, research is needed 
to investigate key areas of tenderness and growth characteristics of forage-finished cattle.  
Moreover, research into breed related-differences of forage-finished cattle is needed to identify 
possible genetic and physiological differences.   
72 
 
Chapter VI 
 
Tables and Figures 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
73 
 
 
Table 1. Least squares means for carcass characteristics of serially harvested forage-fed beef steers. 
a,b,c,d,eMeans within a column lacking a common superscript differ (P < 0.05). 
1Groups- Harvested every 56-d; Group 1: Control, no grazing; Groups 2, 3, and 4, 56, 112, 168 d grazing ryegrass, respectively; 
Group 5, 168 d grazing ryegrass, 28 d grazing bermudagrass and tall fescue, 28 d grazing crabgrass; Group 6,168 d grazing ryegrass, 
28 d grazing bermudagrass and tall fescue, 84 d grazing crabgrass. 
2Marbling Score: 350 ? The first number (3) is the level and the last two numbers (50) are the degree; 1=Practically devoid, 2=Traces, 
3= Slight, 4=Small. 
 
 
 
 
 
 
 
Group1 BW, kg HCW, kg  Backfat, cm LM Area, cm2 KPH, % 24 h pH Bone Maturity Marbling Score2 Yield Grade ADG, kg 
1 328.22d 160.57e 0.215c 45.10d     1.00d             6.04a 146.00b 182.00d 2.1b - 
2 398.94c 210.24d 0.432c 57.29c  1.625b 5.80b 134.00cd 269.00c 2.0b 1.15a 
3 430.50c 239.22c 0.315c 71.61b 1.175cd 5.78b 132.00d 289.00c 1.5c 0.93b 
4 504.53b 275.29b 0.853b 75.42ab 1.725ab 5.79b 140.00bc 349.00b 2.3b 1.05ab 
5 496.78b 268.71b 0.725b 81.35a 1.300c 5.79b 134.00cd 351.00b 1.6bc 0.74c 
6 545.22a 301.46a 1.104a 75.23a 1.875a 5.74b 158.00a 401.00a 2.8a 0.77c 
SEM 14.01 7.97 0.05 2.90 0.08 0.07 2.13 14.08 0.17 0.05 
P-Value < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.038 < 0.001 < 0.001 < 0.001 < 0.001 
74 
 
Table 2. Least squares means for instrumental color characteristics of muscle and fat at the 12th rib 24 h postmortem of serially 
harvested forage-fed beef steers 
Group1  Muscle  Fat  L*2 a*3 b*4  L*2 a*3 b*4 
1  29.59 19.60c 15.52de  - - - 
2  29.50 22.01ab 19.39a  72.18b 9.05 24.40bc 
3  28.03 20.83bc 17.26bc  70.73b 10.40 26.52ab 
4  28.24 18.69c 13.97e  71.26b 9.51 22.84c 
5  29.85 20.42bc 15.82cd  72.26b 9.74 26.78ab 
6  30.34 22.95a 17.92ab  76.56a 10.41 28.61a 
SEM  1.27 0.58 0.61  0.95 0.90 1.19 
P-Value  0.752 < 0.001 < 0.001  < 0.001 0.790 0.013 
a,b,c,d,eMeans within a column lacking a common superscript differ (P < 0.05). 
1Groups- Harvested every 56-d; Group 1: Control, no grazing; Groups 2, 3, and 4, 56, 112, 168 d grazing ryegrass, respectively; 
Group 5, 168 d grazing ryegrass, 28 d grazing bermudagrass and tall fescue, 28 d grazing crabgrass; Group 6,168 d grazing ryegrass, 
28 d grazing bermudagrass and tall fescue, 84 d grazing crabgrass. 
2L* - Lightness: 0=Black; 100= White. 
3a* - Redness: -100=Green; 100=Red. 
4b*- Yellowness: -100=Blue; 100=Yellow. 
 
 
 
 
 
 
 
 
 
75 
 
Table 3. Least squares means for group x day interaction for L*, a* and b* values of simulated retail display loin steaks of serially 
harvested forage-fed beef steers 
Group1 
 L*2  a*3  b*4 
 Day 0 Day 6  Day 0 Day 6  Day 0 Day 6 
1  33.35c 33.85c  21.67a 9.25c  21.43a 9.62e 
2  38.98a 32.74cd  18.84b 9.19c  14.71bc 11.64d 
3  37.64ab 30.47ef  19.50b 9.02c  14.83bc 9.18ef 
4  37.05b 29.84f  19.19b 9.80c  14.71bc 8.76ef 
5  37.88ab 31.75de  19.31b 7.78d  14.06c 7.54g 
6  37.35b 31.49de  20.83a 7.77d  15.19b 8.44fg 
SEM  0.5318  0.4316  0.3895 
P-Value 
Group  < 0.001  < 0.001  < 0.001 
Day  < 0.004  < 0.001  < 0.001 
Interaction  < 0.001  < 0.001  < 0.001 
a,b,c,d,e,f,gMeans within an effect lacking a common superscript differ (P < 0.05). 
1Groups- Harvested every 56-d; Group 1: Control, no grazing; Groups 2, 3, and 4, 56, 112, 168 d grazing ryegrass, respectively; 
Group 5, 168 d grazing ryegrass, 28 d grazing bermudagrass and tall fescue, 28 d grazing crabgrass; Group 6,168 d grazing ryegrass, 
28 d grazing bermudagrass and tall fescue, 84 d grazing crabgrass. 
2L* - Lightness: 0=Black; 100= White. 
3a* - Redness: -100=Green; 100=Red. 
4b*- Yellowness: -100=Blue; 100=Yellow. 
 
 
 
76 
 
Table 4. Least squares means for group x day interaction for Hue Angle, Chroma and 630/580 nm ratio values of simulated retail 
display loin steaks of serially harvested forage-fed beef steers 
Group1 
 Hue Angle2  Chroma3  630/580 nm Ratio4 
 Day 0 Day 6  Day 0 Day 6  Day 0 Day 6 
1  44.91cd 46.29bc  30.49a 13.39e  6.86a 6.10b 
2  37.93f 51.15a  23.92c 14.93d  4.91c 5.08c 
3  37.19f 45.48bcd  24.50bc 12.92ef  5.34c 5.33c 
4  37.32f 41.72e  24.19c 13.18e  2.34f 2.47ef 
5  35.98f 44.25d  23.89c 10.86g  3.12d 3.02de 
6  36.06f 47.12b  25.78b 11.52g  2.40ef 2.67def 
SEM  0.7077  0.5544  0.2311 
P-value 
Group  < 0.001  < 0.001  0.630 
Day  < 0.001  < 0.001  < 0.001 
Group x day  < 0.001   < 0.001  0.056 
a,b,c,d,e,f,gMeans within an effect lacking a common superscript differ (P < 0.05). 
1Groups- Harvested every 56-d; Group 1: Control, no grazing; Groups 2, 3, and 4, 56, 112, 168 d grazing ryegrass, respectively; 
Group 5, 168 d grazing ryegrass, 28 d grazing bermudagrass and tall fescue, 28 d grazing crabgrass; Group 6,168 d grazing ryegrass, 
28 d grazing bermudagrass and tall fescue, 84 d grazing crabgrass. 
2Hue Angle: Lower values indicate truer red color. 
3Chroma: Higher values indicate more vivid red color. 
4630/580 nm ratio: Higher numbers indicate larger oxymyoglobin to metmyoglobin proportion. 
 
 
 
77 
 
Table 5. Least squares means for cook loss, Warner-Bratzler shear force and TBARS of serially harvested forage-fed beef steers 
  Cook loss, %  Warner-Bratzler Shear Force, kg  TBARS2, mg / kg of meat 
Group1  14d 21d DIS  14d 21 d DIS  14d 21 d DIS 
1  28.88ab 31.74a 27.03bc  6.18ef 5.33ef 4.66f  1.07abc 0.88cde 1.36ab 
2  26.79bc 28.68ab 23.15de  8.55a 8.27ab 7.02bcd  0.92bcd 0.88cde 1.50a 
3  22.97def - 22.44def  8.11abc - 5.43ef  0.72cde - 0.40ef 
4  23.89cde 21.65def 21.87def  7.16abcd 6.27de 4.43f  0.89bcde 0.49def 0.46def 
5  24.00cde 23.27de 19.85f  5.96ef 6.17ef 4.58f  0.00f 0.84cde 0.42def 
6  24.67cd 20.90ef 21.66def  6.80cd 5.14ef 4.77f  0.00f 0.72cde 0.59cde 
SEM  1.1213  0.5223  0.1806 
P-value 
Group  < 0.001  < 0.001  < 0.001 
Aging period  < 0.001  < 0.001  0.184 
Interaction  0.024  0.311  < 0.001 
a,b,c,d,e,fMeans within an effect lacking a common superscript differ (P < 0.05) 
1Groups- Harvested every 56-d; Group 1: Control, no grazing; Groups 2, 3, and 4, 56, 112, 168 d grazing ryegrass, respectively; 
Group 5, 168 d grazing ryegrass, 28 d grazing bermudagrass and tall fescue, 28 d grazing crabgrass; Group 6,168 d grazing ryegrass, 
28 d grazing bermudagrass and tall fescue, 84 d grazing crabgrass. 
2TBARS: Thiobarbituric Reactive Substances- Expressed as mg malondialdehyde / kg of meat 
 
 
 
 
 
 
78 
 
Table 6. Least squares means for initial and sustained juiciness for sensory evaluation of serially harvested forage-fed beef steers 
Group1 
 Initial Juiciness2  Sustained Juiciness2 
 14 d 21 d DIS  14 d 21 d DIS 
1  5.31cdef 4.94f 5.35cde  5.03cdefg 4.64h 5.26abc 
2  5.37cde 5.07def 5.02ef  4.97cdefgh 4.71gh 4.80defgh 
3  5.54abc - 5.31cdef  5.19abcd - 5.07cdefg 
4  5.47bc 5.40cd 5.18cdef  5.10cdef 5.20abc 4.76fgh 
5  5.83ab 5.46c 5.24cdef  5.52a 5.13bcdef 4.79efgh 
6  5.84a 5.42cd 5.51abc  5.50ab 5.15abcde 5.15abcde 
SEM  0.13  0.14 
P-value 
Group  < 0.001  0.004 
Aging period  0.010  0.071 
Interaction  0.021  < 0.001 
a,b,c,d,e,f,g,hMeans within an effect lacking a common superscript differ (P < 0.05). 
1Groups- Harvested every 56-d; Group 1: Control, no grazing; Groups 2, 3, and 4, 56, 112, 168 d grazing ryegrass, respectively; 
Group 5, 168 d grazing ryegrass, 28 d grazing bermudagrass and tall fescue, 28 d grazing crabgrass; Group 6,168 d grazing ryegrass, 
28 d grazing bermudagrass and tall fescue, 84 d grazing crabgrass. 
25= Slightly juicy; 4= Slightly dry. 
 
 
 
79 
 
Table 7. Least squares means for initial and sustained tenderness for sensory evaluation of serially harvested forage-fed beef steers 
Group1 
 Initial Tenderness2  Sustained Tenderness2 
 14 d 21 d DIS  14 d 21 d DIS 
1  5.99a 5.09bcdef 5.55abc  5.65a 4.58bcdef 5.19abc 
2  4.49fgh 4.67efgh 4.05h  3.79ghi 4.33defgh 3.39i 
3  4.13gh - 4.82defg  3.65hi - 4.20efghi 
4  4.65efgh 5.52abc 5.23bcde  4.10fghi 5.12abcd 4.72bcdef 
5  5.67ab 5.47abcd 4.88cdef  5.33ab 5.28abc 4.51cdefg 
6  5.23bcde 5.33abcde 4.94cdef  4.75bcdef 5.08abcde 4.60bcdef 
SEM  0.24  0.28 
P-value 
Group  < 0.001  < 0.001 
Aging period   0.002  < 0.001 
Interaction  0.133  0.279 
 
a,b,c,d,e,f,g,h,iMeans within an effect lacking a common superscript differ (P < 0.05). 
1Groups- Harvested every 56-d; Group 1: Control, no grazing; Groups 2, 3, and 4, 56, 112, 168 d grazing ryegrass, respectively; 
Group 5, 168 d grazing ryegrass, 28 d grazing bermudagrass and tall fescue, 28 d grazing crabgrass; Group 6,168 d grazing ryegrass, 
28 d grazing bermudagrass and tall fescue, 84 d grazing crabgrass. 
25= Slightly tender; 3=Moderately tough. 
 
 
80 
 
Table 8. Least squares means for beef flavor and off flavor intensity for sensory evaluation of serially harvested forage-fed beef steers 
Group1 
 Beef Flavor Intensity2  Off Flavor Intensity2 
 14 d 21 d DIS  14 d 21 d DIS 
1  4.66cd 4.62d 4.80bcd  2.36bc 1.43d 1.31d 
2  4.78bcd 4.78bcd 4.56d  1.58d 2.51b 1.70d 
3  4.99abc - 4.84bcd  1.57d - 2.57b 
4  4.92abcd 4.62d 4.86bcd  1.54d 3.23a 2.40b 
5  5.07ab 4.78bcd 5.09ab  1.42d 3.49a 1.33d 
6  4.79bcd 5.24a 5.28a  1.37d 1.80cd 1.50d 
SEM  0.13  0.20 
P-value 
Group  < 0.001  < 0.001 
Aging period  0.391  < 0.001 
Interaction  0.067   0.002 
 
a,b,c,dMeans within an effect lacking a common superscript differ (P < 0.05). 
1Groups- Harvested every 56-d; Group 1: Control, no grazing; Groups 2, 3, and 4, 56, 112, 168 d grazing ryegrass, respectively; 
Group 5, 168 d grazing ryegrass, 28 d grazing bermudagrass and tall fescue, 28 d grazing crabgrass; Group 6,168 d grazing ryegrass, 
28 d grazing bermudagrass and tall fescue, 84 d grazing crabgrass. 
25Slightly intense beef flavor, moderate off flavor; 1= Extremely bland, no off flavor. 
 
 
81 
 
Table 9. Least squares means for other and bloody off flavors sensory evaluation of serially harvested forage-fed beef steers 
Group1 
 Other2, %  Bloody2, % 
 14 d 21 d DIS  14 d 21 d DIS 
1  0.00b 0.00b 0.00b  1.43 3.81 0.00 
2  0.00b 5.03a 2.86ab  0.00 0.00 1.43 
3  1.67ab - 5.00a  1.67 - 0.00 
4  0.00b 0.00b 0.00b  0.00 0.00 0.00 
5  0.00b 0.00b 0.00b  1.67 0.00 0.00 
6  0.00b 0.00b 4.00a  0.00 0.00 0.00 
SEM  1.42  0.94 
P-value 
Group  0.026  0.274 
Aging period  0.104  0.517 
Interaction  0.379  0.236 
a,bMeans within an effect lacking a common superscript differ (P < 0.05). 
1Groups- Harvested every 56-d; Group 1: Control, no grazing; Groups 2, 3, and 4, 56, 112, 168 d grazing ryegrass, respectively; 
Group 5, 168 d grazing ryegrass, 28 d grazing bermudagrass and tall fescue, 28 d grazing crabgrass; Group 6,168 d grazing ryegrass, 
28 d grazing bermudagrass and tall fescue, 84 d grazing crabgrass. 
2Means are expressed as a percentage of the number of times that the off-flavor was identified within a sample. 
 
 
82 
 
Table 10. Least squares means for rancid and grassy off flavors sensory evaluation of serially harvested forage-fed beef steers 
Group1 
 Rancid2, %  Grassy2, % 
 14 d 21 d DIS  14 d 21 d DIS 
1  5.10e 6.30de 42.05a  9.82cd 5.03d 14.62cd 
2  19.35cd 7.14de 49.00a  15.59cd 14.13cd 15.81cd 
3  9.53de - 42.38a  14.29cd - 9.29cd 
4  20.24cd 39.67ab 38.33ab  5.95d 14.00cd 28.33ab 
5  13.34cde 6.00de 40.95ab  5.00d 11.33cd 34.53a 
6  6.67de 4.00e 27.43bc  10.00cd 18.00bc 7.43cd 
SEM  5.14  4.01 
P-value 
Group  < 0.001  0.222 
Aging period  < 0.001  0.001 
Interaction   0.004  < 0.001 
a,b,c,d,eMeans within an effect lacking a common superscript differ (P < 0.05). 
1Groups- Harvested every 56-d; Group 1: Control, no grazing; Groups 2, 3, and 4, 56, 112, 168 d grazing ryegrass, respectively; 
Group 5, 168 d grazing ryegrass, 28 d grazing bermudagrass and tall fescue, 28 d grazing crabgrass; Group 6,168 d grazing ryegrass, 
28 d grazing bermudagrass and tall fescue, 84 d grazing crabgrass. 
2Means are expressed as a percentage of the number of times that the off-flavor was identified within a sample. 
 
 
83 
 
Table 11. Least squares means for fiber type area and percentage of serially harvested forage-fed beef steers 
  Area, ?m2  Percentage 
Group1  Type Ia Type IIa Type IIb  Type Ia Type IIa Type IIb 
1  1821.07ij 2308.76gh 3182.94de  37.61abc 28.36f 34.03cde 
2  1760.35j 2557.80fg 3619.96c  40.88a 28.72f 30.40ef 
3  2280.13gh 3436.25cd 4997.83a  38.97ab 30.27ef 30.83ef 
4  2052.04hij 3062.65de 4799.95a  34.56bcde 30.87ef 34.41bcde 
5  2165.12ghij 3051.58def 4644.60ab  32.28def 30.53ef 37.19abc 
6  2203.85ghi 2976.92ef 4247.85b  36.26abcd 31.86def 31.88def 
SEM  152.27  1.68 
P-value 
Group  < 0.001  1.00 
Fiber type  < 0.001  < 0.001 
Interaction  0.001  0.001 
a,b,c,d,e,f,g,h,i,jMeans within an effect lacking a common superscript differ (P < 0.05). 
1Groups- Harvested every 56-d; Group 1: Control, no grazing; Groups 2, 3, and 4, 56, 112, 168 d grazing ryegrass, respectively; 
Group 5, 168 d grazing ryegrass, 28 d grazing bermudagrass and tall fescue, 28 d grazing crabgrass; Group 6,168 d grazing ryegrass, 
28 d grazing bermudagrass and tall fescue, 84 d grazing crabgrass. 
 
 
 
 
 
84 
 
Table 12.  Least squares means for fatty acid profiles (mg / g meat) of serially harvested forage-fed beef steers 
 
a,b,cMeans within a row lacking a common superscript differ (P < 0.05). 
1Groups- Harvested every 56-d; Group 1: Control, no grazing; Groups 2, 3, and 4, 56, 112, 168 d grazing ryegrass, 
respectively; Group 5, 168 d grazing ryegrass, 28 d grazing bermudagrass and tall fescue, 28 d grazing crabgrass; 
Group 6,168 d grazing ryegrass, 28 d grazing bermudagrass and tall fescue, 84 d grazing crabgrass. 
 
  Group1     
Fatty Acid, 
mg/g 
 1 2 3 4 5 6  SEM  P-value 
12:0  0.017 0.031 0.000 0.005 0.011 0.008  0.008  0.096 
12:1  0.029 0.000 0.000 0.000 0.000 0.000  0.012  0.386 
13:0  0.000 0.000 0.000 0.000 0.000 0.000  0.000  - 
13:1  0.203 0.185 0.182 0.134 0.179 0.130  0.034  0.576 
14:0  0.495 0.446 0.150 0.390 0.516 0.428  0.104  0.166 
14:1  0.113 0.092 0.036 0.121 0.115 0.082  0.028  0.267 
15:0  0.089 0.079 0.35 0.60 0.109 0.082  0.023  0.282 
15:1  0.095 0.111 0.158 0.085 0.125 0.089  0.024  0.259 
16:0  3.695 3.811 2.292 4.255 5.197 4.458  0.712  0.102 
16:1 t  0.074b 0.109ab 0.138a 0.132a 0.135a 0.090b  0.014  0.009 
16:1  0.462 0.467 0.320 0.605 0.613 0.536  0.090  0.194 
17:0  0.174 0.154 0.072 0.152 0.230 0.172  0.038  0.126 
17:1  0.151 0.143 0.091 0.159 0.157 0.138  0.022  0.266 
18:0  2.459 2.551 1.624 2.560 3.876 2.885  0.524  0.085 
18:1 n9 t  0.061 0.044 0.026 0.064 0.059 0.060  0.014  0.372 
18:1  0.138 0.217 0.395 0.115 0.122 0.090  0.105  0.328 
18:1 n9  5.253 5.239 3.131 6.149 7.530 6.269  1.012  0.067 
18:1 n7  0.449a 0.379ab 0.254b 0.511a 0.535a 0.445a  0.061  0.023 
18:2 n6 t  0.087 0.066 0.025 0.056 0.121 0.065  0.025  0.146 
18:2 n6  1.316a 0.937b 0.943b 0.943b 1.273a 0.867b  0.073  <0.001 
18:3 n6  0.000 0.000 0.031 0.000 0.044 0.045  0.023  - 
19:1  0.000 0.000 0.000 0.000 0.000 0.035  0.015  0.462 
18:3 n3  0.425a 0.416a 0.420a 0.451a 0.507a 0.233b  0.053  0.012 
20:0  0.000 0.031 0.000 0.000 0.008 0.018  0.014  0.540 
20:1 n15  0.041 0.016 0.015 0.038 0.042 0.030  0.012  0.414 
20:1 n12  0.000 0.009 0.000 0.004 0.007 0.013  0.006  0.572 
20:1 n9  0.000 0.000 0.000 0.000 0.007 0.015  0.005  0.154 
20:2  0.081 0.052 0.062 0.074 0.054 0.049  0.009  0.143 
20:3 n6  0.156a 0.128a 0.116b 0.117b 0.140ab 0.093b  0.010  0.002 
20:4  0.653a 0.537b 0.564ab 0.476b 0.553ab 0.339c  0.039  <0.001 
20:3 n3  0.089 0.084 0.076 0.104 0.097 0.055  0.013  0.129 
22:0  0.371a 0.326a 0.347a 0.341a 0.387a 0.221b  0.029  0.001 
20:5  0.000 0.032 0.000 0.000 0.000 0.015  0.014  0.501 
22:1  0.000 0.000 0.000 0.000 0.000 0.004  0.001  0.466 
22:2  0.000 0.000 0.000 0.000 0.000 0.000  0.000  - 
22:4  0.000 0.000 0.000 0.000 0.004 0.000  0.001  0.466 
22:3  0.000 0.000 0.000 0.000 0.000 0.000  0.000  - 
24:0  0.000 0.000 0.000 0.000 0.000 0.006  0.002  0.466 
22:5  0.345abc 0.321bc 0.409ab 0.423a 0.414a 0.289c  0.032  0.014 
22:6  0.000 0.049 0.026 0.021 0.018 0.000  0.016  0.322 
24:1  0.000 0.000 0.000 0.000 0.000 0.000  0.000  - 
SFA  7.299 7.429 4.522 7.762 10.335 8.277  1.393  0.111 
MUFA  7.069 7.010 4.745 8.118 9.625 8.026  1.202  0.110 
PUFA  3.152ab 2.620b 2.671b 2.665b 3.225a 2.051c  0.195  <0.001 
n6:n3  1.837ab 1.303bc 1.299bc 1.127c 1.777b 2.191a  0.230  0.009 
85 
 
Table 13. Least squares means for percentage of fatty acid profile of serially harvested forage-fed beef steers 
a,b,cMeans within a row lacking a common superscript differ (P < 0.05) 
1Groups- Harvested every 56-d; Group 1: Control, no grazing; Groups 2, 3, and 4, 56, 112, 168 d grazing ryegrass, 
respectively; Group 5, 168 d grazing ryegrass, 28 d grazing bermudagrass and tall fescue, 28 d grazing crabgrass; 
Group 6,168 d grazing ryegrass, 28 d grazing bermudagrass and tall fescue, 84 d grazing crabgrass. 
 
 
 Group     
Fatty Acid, 
% 
 1 2 3 4 5 6  SEM  P-value 
12:0  0.087 0.237 0.000 0.018 0.031 0.030  0.073  0.225 
12:1  0.181 0.000 0.000 0.000 0.000 0.000  0.071  0.386 
13:0  0.000 0.000 0.000 0.000 0.000 0.000  0.000  - 
13:1  1.156 1.186 1.551 0.877 1.074 0.883  0.260  0.460 
14:0  2.689a 2.188ab 1.247c 1.961b 1.981b 2.145ab  0.240  0.005 
14:1  0.596 0.402 0.305 0.575 0.432 0.393  0.104  0.318 
15:0  0.501 0.373 0.299 0.296 0.379 0.402  0.064  0.237 
15:1  0.549 0.739 1.392 0.569 0.727 0.591  0.216  0.068 
16:0  20.847bc 21.301bc 19.162c 22.459ab 21.600c 23.878a  0.695  < 0.001 
16:1 t  0.419c 0.771b 1.159a 0.799b 0.659bc 0.528bc  0.105  < 0.001 
16:1  2.563 2.671 2.670 3.116 2.591 2.897  0.166  0.133 
17:0  0.993 0.852 0.574 0.797 0.842 0.844  0.096  0.094 
17:1  0.860 0.872 0.744 0.866 0.815 0.771  0.072  0.432 
18:0  14.172 14.601 13.552 13.804 15.810 15.219  0.561  0.058 
18:1 n9 t  0.341 0.174 0.212 0.373 0.260 0.286  0.066  0.308 
18:1  0.826 1.279 3.672 0.687 0.734 0.681  0.996  0.232 
18:1 n9  29.570ab 29.932ab 25.588b 32.390a 31.432a 33.542a  1.588  0.013 
18:1 n7  2.607 2.381 2.092 2.726 2.396 2.451  0.199  0.309 
18:2 n6 t  0.480 0.256 0.192 0.285 0.428 0.288  0.079  0.105 
18:2 n6  7.768a 6.447ab 8.007a 5.490b 6.437ab 5.334b  0.660  0.019 
18:3 n6  0.000 0.000 0.245 0.000 0.409 0.504  0.242  0.124 
19:1  0.000 0.000 0.000 0.000 0.000 0.154  0.068  0.462 
18:3 n3  2.485b 2.706ab 3.617a 2.627b 2.329b 1.190c  0.353  < 0.001 
20:0  0.000 0.214 0.000 0.000 0.015 0.071  0.088  0.472 
20:1 n15  0.206 0.056 0.116 0.179 0.168 0.124  0.051  0.371 
20:1 n12  0.000 0.024 0.000 0.013 0.014 0.052  0.018  0.324 
20:1 n9  0.000 0.000 0.000 0.000 0.013 0.061  0.017  0.082 
20:2  0.488ab 0.326bcd 0.509a 0.435abc 0.228d 0.306cd  0.062  0.009 
20:3 n6  0.924ab 0.871ab 0.987ab 0.683bc 0.726bc 0.582c  0.092  0.019 
20:4  3.922ab 3.819ab 4.787a 2.787bc 2.901bc 2.211c  0.415  < 0.001 
20:3 n3  0.521 0.507 0.654 0.597 0.446 0.309  0.086  0.082 
22:0  2.187b 2.145b 2.967a 2.016bc 2.057bc 1.396c  0.261  0.004 
20:5  0.000 0.220 0.000 0.000 0.000 0.064  0.091  0.461 
22:1  0.000 0.000 0.000 0.000 0.000 0.017  0.007  0.466 
22:2  0.000 0.000 0.000 0.000 0.000 0.000  0.000  - 
22:4  0.000 0.000 0.000 0.000 0.008 0.000  0.003  0.466 
22:3  0.000 0.000 0.000 0.000 0.000 0.000  0.000  - 
24:0  0.000 0.000 0.000 0.000 0.000 0.026  0.011  0.466 
22:5  2.062bc 2.148bc 3.456a 2.475b 2.097b 1.774c  0.254  < 0.001 
22:6  0.000 0.303 0.245 0.101 0.060 0.000  0.105  0.201 
24:1  0.000 0.000 0.000 0.000 0.000 0.000  0.000  - 
SFA  41.476a 41.911a 37.800b 41.350a 42.714a 44.010a  1.178  0.013 
MUFA  39.874b 40.488b 39.501b 43.170ab 41.217ab 43.429a  0.976  0.015 
PUFA  18.651ab 17.602b 22.700a 15.481bc 16.069bc 12.560c  1.590  0.001 
n6:n3  1.837ab 1.303bc 1.299bc 1.127c 1.777b 2.191a  0.230  0.009 
86 
 
Table 14. Least squares means for instrumental color characteristics for simulated retail display of LM steaks from forage- and grain-
finished cattle  
Characteristic 
 Day 0  Day 6     P-Value  
 Grain Forage  Grain Forage  SEM  Day Finishing type 
Day x 
finishing 
type 
L*1  43.38a,y 39.84b,y  39.69a,z 35.64b,z  0.35  < 0.001 < 0.001 0.240 
a*2  23.04c 20.72d  6.53e 6.89e  0.20  < 0.001 < 0.001 < 0.001 
b*3  18.94a,y 14.85b,y  13.91a,z 9.56b,z  0.22  < 0.001 < 0.001 0.481 
Hue Angle4  39.42e 35.50f  64.87c 54.06d  0.55  < 0.001 < 0.001 < 0.001 
Chroma5  29.85a,y 25.50b,y  15.38a,z 11.88b,z  0.26  < 0.001 < 0.001 0.067 
630/580 nm6  5.67c 5.07d  1.28f 1.76e  0.09  < 0.001 0.548 < 0.001 
a,bMeans within a row lacking a common superscript differ (P < 0.05) for finishing type 
y,zMeans within a row lacking a common superscript differ (P < 0.05) for day 
c,d,e,fMeans within a row lacking a common superscript differ (P < 0.05) for day x feed interactions 
1L* - Lightness: 0=Black; 100= White 
2a* - Redness: -100=Green; 100=Red 
3b*- Yellowness: -100=Blue; 100=Yellow 
4Hue Angle: Lower values indicate truer red color 
5Chroma: Higher values indicate more vivid red color 
6630/580 nm ratio: Higher numbers indicate larger oxymyoglobin to metmyoglobin proportion 
 
 
 
 
 
 
 
87 
 
Table 15. Least squares means for fiber type area and percent from striploins of forage- and grain-finished cattle 
Item  Area, ?m
2  % 
 Grain Forage  Grain Forage 
Type Ia  2388.78a,z 1858.44b,z  26.67d 36.60c 
Type IIa  2986.25a,y 2456.85b,y  37.77c 28.60d 
Type IIb  4357.59a,x 3506.93b,x  38.55c 35.12c 
SEM  130.76 145.07  1.83 1.95 
P-value 
Finishing type   < 0.001  1.00 
Fiber type  < 0.001  0.007 
Interaction  0.406  <0.001 
a,bWithin a variable, means lacking a common superscript differ (P < 0.05) for finishing type 
y,zWithin a variable, means lacking a common superscript differ (P < 0.05) for fiber type 
c,dWithin a variable, means lacking a common superscript differ (P < 0.05) for the interaction 
 
 
 
 
 
 
 
 
 
 
88 
 
Table 16. Least squares means for sensory evaluation, cook loss and Warner-Bratzler shear force of LM steaks from forage- and grain-
finished cattle 
Characteristic 
 Fresh  Display     P-Value  
 Grain Forage  Grain Forage  SEM  Finishing type Age 
Finishing 
type x 
Age 
Initial Juiciness1  5.58b,y 6.03a,y  5.41b,z 5.58a,z  0.08  < 0.001 < 0.001 0.125 
Sustained Juiciness1  5.17b,y 5.83a,y  5.00b,z 5.30a,z  0.09  < 0.001 < 0.001 0.068 
Initial Tenderness2  6.43a 5.93b  6.34a 5.81b  0.09  < 0.001 0.314 0.862 
Sustained Tenderness2  6.16a 5.51b  6.04a 5.51b  0.11  < 0.001 0.384 0.826 
Beef Flavor Intensity3  5.29y 5.43y  4.75z 4.87z  0.10  0.239 < 0.001 0.876 
Off Flavor Intensity3  1.36b,z 1.61a,z  3.81b,y 4.45a,y  0.18  0.012 < 0.001 0.314 
Cook loss, %  24.06 22.60  24.06 22.67  1.14  0.2209 0.976 0.974 
WB Shear Force, kg  2.99b 4.13a  2.94b 3.61a  0.15  < 0.001 0.071 0.130 
a,bMeans within a row lacking a common superscript differ (P < 0.05) for finishing type 
y,zMeans within a row lacking a common superscript differ (P < 0.05) for age 
18= Extremely juicy; 1= Extremely dry 
28= Extremely tender; 1=tough 
38= Extremely intense beef flavor, off flavor; 1= Extremely bland, no off flavor 
 
 
 
 
 
 
 
 
89 
 
Table 17. Least squares means for sensory evaluation off flavors, and TBARS of LM steaks from forage- and grain-finished cattle 
Characteristic 
 Fresh  Display    P-Value 
 Grain Forage  Grain Forage  SEM  Finishing type Age 
Finishing 
type x 
Age 
Other  0.00b,z 0.00a,z  1.19b,y 5.95a,y  1.29  0.005 0.033 0.061 
Rancid  4.23e 18.45d  75.99c 75.29c  3.68  0.063 < 0.001 0.041 
Bloody  0.00 0.88  0.00 0.00  0.50  0.373 0.373 0.373 
Bitter  0.00 0.00  1.19 2.14  1.07  0.648 0.113 0.648 
Grassy  8.45 15.53  7.45 10.62  3.18  0.103 0.344 0.531 
Livery  0.00 0.00  0.00 0.00  0.00  - - - 
Salty  0.00 0.00  0.00 0.00  0.00  - - - 
Metallic  2.98 0.75  1.19 1.43  1.18  0.388 0.629 0.285 
TBARS1  0.42d 0.55d  1.64c 0.74d  1.14  < 0.001 0.014  0.001 
a,bMeans within a row lacking a common superscript differ (P < 0.05) for finishing type 
y,zMeans within a row lacking a common superscript differ (P < 0.05) for age 
c,d,e,Means within a row lacking a common superscript differ (P < 0.05) for interaction 
1TBARS: Thiobarbituric Reactive Substances- Expressed as mg malondialdehyde / kg of meat 
 
 
 
 
90 
 
Table 18.  Least squares means for fatty acid profiles (mg / g meat) of from LM from forage- and 
grain-finished cattle 
Fatty Acid, mg / g meat  Grain Forage  SEM  P-value 
12:0  0.027a 0.008b  0.006  0.037 
12:1  0.000 0.000  -  - 
13:0  0.005 0.000  0.002  0.107 
13:1  0.033 0.042  0.008  0.433 
14:0  1.356a 0.533b  0.250  0.026 
14:1  0.291 0.181  0.054  0.160 
15:0  0.261a 0.073b  0.052  0.015 
15:1  0.425 0.461  0.058  0.663 
16:0  11.317a 5.514b  1.679  0.020 
16:1 t  0.129 0.089  0.016  0.095 
16:1  1.244 0.810  0.183  0.103 
17:0  0.725a 0.207b  0.136  0.011 
17:1  0.456a 0.208b  0.080  0.036 
18:0  6.049a 3.016b  0.889  0.021 
18:1 n9 t  0.450a 0.010b  0.113  0.009 
18:1  0.740 0.158  0.222  0.072 
18:1 n9  15.646 8.66  2.554  0.062 
18:1 n7  0.709 0.261  0.193  0.110 
18:2 n6 t  0.112 0.095  0.031  0.706 
18:2 n6  3.023a 1.402b  0.222  < 0.001 
18:3 n6  0.024a 0.014b  0.009  0.425 
19:1  0.000 0.000  -  - 
18:3 n3  0.084b 0.354a  0.019  < 0.001 
20:0  0.016 0.008  0.006  0.380 
20:1 n15  0.073 0.067  0.018  0.804 
20:1 n12  0.019 0.009  0.006  0.301 
20:1 n9  0.057 0.019  0.015  0.076 
20:2  0.039 0.031  0.009  0.527 
20:3 n6  0.215a 0.107b  0.017  < 0.001 
20:4  0.793a 0.478b  0.038  < 0.001 
20:3 n3  0.000b 0.039a  0.007  < 0.001 
22:0  0.063b 0.241a  0.016  < 0.001 
20:5  0.000 0.000  -  - 
22:1  0.000 0.000  -  - 
22:2  0.000 0.000  -  - 
22:4  0.089a 0.007b  0.010  < 0.001 
22:3  0.000 0.000  -  - 
24:0  0.000 0.000  -  - 
22:5  0.170b 0.301a  0.014  < 0.001 
22:6  0.000 0.000  -  - 
24:1  0.006 0.000  0.004  0.324 
SFA  19.817a 9.599b  2.983  0.021 
MUFA  20.277a 10.974b  3.023  0.037 
PUFA  4.549a 2.828b  0.277  < 0.001 
n6:n3  13.450a 2.523b  1.175  < 0.001 
a,bWithin a row, means lacking a common superscript differ (P < 0.05) 
 
91 
 
Table 19. Least squares means for fatty acid profiles (%) of LM from forage- and grain-finished 
cattle 
Fatty Acid, %  Grain Forage  SEM  P-value 
12:0  0.042 0.019  0.009  0.073 
12:1  0.000 0.000  -  - 
13:0  0.005 0.000  0.002  0.078 
13:1  0.097b 0.223a  0.044  0.049 
14:0  2.649a 1.931b  0.199  0.015 
14:1  0.603 0.897  0.223  0.359 
15:0  0.485a 0.226b  0.047  < 0.001 
15:1  1.618b 2.802a  0.407  0.047 
16:0  24.741a 22.084b  0.656  0.007 
16:1 t  0.304b 0.439a  0.033  0.007 
16:1  2.787b 3.464a  0.107  < 0.001 
17:0  1.408a 0.693b  0.100  < 0.001 
17:1  0.932 0.879  0.043  0.386 
18:0  13.173 12.387  0.371  0.143 
18:1 n9 t  1.741a 0.024b  0.366  0.002 
18:1  1.601 0.532  0.456  0.107 
18:1 n9  32.803 35.741  1.052  0.057 
18:1 n7  1.197 0.587  0.347  0.222 
18:2 n6 t  0.164b 0.371a  0.061  0.022 
18:2 n6  8.371 7.475  0.937  0.503 
18:3 n6  0.028b 0.031a  0.014  0.008 
19:1  0.000 0.000  -  0.875 
18:3 n3  0.230b 2.043a  0.195  < 0.001 
20:0  0.018 0.016  0.010  0.883 
20:1 n15  0.157 0.299  0.083  0.233 
20:1 n12  0.021 0.020  0.010  0.919 
20:1 n9  0.076 0.042  0.021  0.255 
20:2  0.081 0.110  0.030  0.499 
20:3 n6  0.685 0.518  0.105  0.271 
20:4  2.839 2.685  0.420  0.797 
20:3 n3  0.000b 0.176a  0.037  0.002 
22:0  0.242b 1.487a  0.172  < 0.001 
20:5  0.000 0.000  -  - 
22:1  0.000 0.000  -  - 
22:2  0.000 0.000  -  - 
22:4  0.275a 0.016b  0.038  < 0.001 
22:3  0.000 0.000  -  - 
24:0  0.000 0.000  -  - 
22:5  0.612b 1.784a  0.187  < 0.001 
22:6  0.000 0.000  -  - 
24:1  0.004 0.000  0.003  0.324 
SFA  42.769a 38.844b  0.0962  0.007 
MUFA  43.946 45.949  0.785  0.080 
PUFA  13.285 15.208  1.523  0.378 
n6:n3  13.450b 2.523b  1.175  < 0.001 
a,bMeans within a row lacking a common superscript differ (P < 0.05)
92 
 
 
 
Figure 1. Grazing and harvest schedule for the serial harvest of forage-finished steers 
Group Start, Day 0 Days; 1-56 Days; 56-112 Days; 112- 168 Days; 168- 224 Days; 224- 280 
1       
2       
3       
4       
5       
6       
7       
 
No Grazing, Control =  Ryegrass=  Warm-Season=  
 
93 
 
Literature Cited 
 
Abraham, H. C., C. E. Murphey, H. R. Cross, G. C. Smith, and W. J. Franks, Jr.1980. Factors 
affecting beef carcass cutability: An evaluation of the USDA Yield Grades for beef. J. 
Anim. Sci. 50:841-851. 
 
Akin, D. E. 1986. Interaction of ruminal bacteria and fungi with southern forages. J. Anim. Sci. 
63:962-977. 
 
Allen, V. G., J. P. Fontenot, R. F. Kelly, and D. R. Notter. 1996. Forage systems for beef 
production from conception to slaughter: III. Finishing systems. J. Anim. Sci. 74:625-
638. 
 
AMSA. 1995. Research guidelines for cookery, sensory evaluation and instrumental 
measurements of fresh meat. Centennial, Colo.: American Meat Science Association in 
cooperation with the National Livestock and Meat Board, now the Natl. Cattlemen?s Beef 
Association. 
 
Arnold, R. N., S. C. Arp, K. K. Scheller, S. N. Williams, and D. M. Schaefer. 1993. Tissue 
equilibration and subcellular distribution of vitamin E relative to myoglobin and lipid 
oxidation in displayed beef. J. Anim. Sci. 71:105-118. 
 
Ashes, J. R., B. D. Siebert, S. K. Gulati, A. Z. Cuthbertson, and T. W. Scott. 1992. Incorporation 
of n-3 fatty acids of fish oil into tissue and serumlipids of ruminants. Lipids. Vol. 27, No. 
8. 
 
Bhattacharya,  A., J. Banu, M. Rahman, J. Causey, and G. Fernandes. 2006. Biological effects of 
conjugated linoleic acids in health and disease. J. Nutr. Biochem. 17:789?810. 
 
Baublits, R. T., A. H. Brown, Jr., F. W. Pohlman, D. C. Rule, Z. B. Johnson, D. O. Onks, C. M. 
Murrieta, C. J. Richards, H. D. Loveday, B. A. Sandelin, and R. B. Pugh. 2006. Fatty acid 
and sensory characteristics of beef from three biological types of cattle grazing cool-
season forages supplemented with soyhulls. Meat Sci. 72:100-107 
 
Baublits, R. T., A. H. Brown, Jr., F. W. Pohlman, Z. B. Johnson, D. O. Onks, H. D. Loveday, R. 
E. Morrow, B. A. Sandelin, W. K. Coblentz, C. J. Richards, and R. B. Pugh. 2004. 
Carcass and beef color characteristics of the three biological types of cattle grazing cool-
season forages supplemented with soyhulls. Meat Sci. 68:297-303. 
94 
 
Beck, P. A., S. A. Gunter, K. S. Lusby, C. P. West, K. B. Watkins, and D. S. Hunnell, III. 2008. 
Animal performance and economic comparison of novel and toxic endophye tall fescues 
to cool-season annuals. J. Anim. Sci. 86:2043-2055. 
 
Bidner, T. D., A. R. Schupp, A. B. Mohamad, N. C. Rumore, R. E. Montgomery, C. P. Bagley, 
and K. W. McMillin. 1986. Acceptability of beef from Angus-Hereford or Angus-
Hereford-Brahman steers finished on all-forage or a high-energy diet. J. Anim. Sci. 
62:381-387. 
 
Bidner, T. D., R. E. Montgomery, C. P. Bagley, and K. W. McMillan. 1985. Influence of 
electrical stimulation, blade tenderization and postmortem vacuum aging upon the 
acceptability of beef finished on forage or grain. J. Anim. Sci. 61:584-589. 
 
Bidner, T. D., A. R. Schupp, R. E. Montgomery, and J. C. Carpenter, Jr. 1981. Acceptability of 
beef finished on all-forage, forage-plus-grain or high energy diets. J. Anim. Sci. 53:1181-
1187. 
 
Bowling, R. A., G. C. Smith, Z. L. Carpenter, T. R. Dutson, and W. M. Oliver. 1977. 
Comparison of forage-finished and grain-finished beef carcasses. J. Anim. Sci. 45:209-
215. 
 
Braden, K. W., J. R. Blanton, Jr., J. L. Montgomery, E. van Santen, V. G. Allen, and M. F. 
Miller. 2007. Tasco supplementation: Effects on carcass characteristics, sensory 
attributes, and retail display shelf-life. J. Anim. Sci. 85:754-768. 
 
Brown, Jr., A. H., P. K. Camfield, C. W. Rowe, L. Y. Rakes, F. W. Pohlman, Z. B. Johnson, G. 
T. Tabler, and B. A. Sandelin. 2007. Effect of beef growth type on cooking loss, 
tenderness, and chemical composition of pasture- or feedlot-developed steers. Asian-
Aust. J. Anim. Sci. 20:1746-1753. 
 
Brown, Jr., A. H., P. K. Camfield, Z. B. Johnson, L. Y. Rakes, F. W. Pohlman, C. J. Brown, B. 
A. Sandelin, and R. T. Baublits. T. 2005. Interaction of beef growth type x production 
system for carcass traits of steers. Asian-Aust. J. Anim. Sci. 18:259-266. 
 
Brown, M. A., A. H. Brown, Jr., W. G. Jackson, and J. R. Miesner. 1997. Genotype x 
environment interactions in Angus, Brahman, and reciprocal cross cows and their calves 
grazing common bermudagrass and endophyte-infected tall fescue pastures. J. Anim. Sci. 
75:920-925. 
 
Brown, R. H. 1984. Growth of C3 and C4 grasses under low N levels. Crop Sci. 25:954-957. 
 
Bruce, H. L., J. L. Stark, and S. L. Beilken. 2004. The effects of finishing diet and postmortem 
ageing on the eating quality on the M. longissimus thoracis of electrically stimulated 
Brahman steer carcasses. Meat Sci. 67:261-268. 
 
95 
 
Browning, Jr., R. 2003. Tall fescue endophyte toxicosis in beef cattle: Clinical mode of action 
and potential mitigation through cattle genetics. Proceedings from the 2003 Beef 
Improvement Federation, Lexington, KY. 
 
Butler, O. D., R. L. Reddish, G. T. King, and R. L. Simms. 1956. Factors contributing to the 
difference in dressing percentage between Hereford and Brahman x Hereford steers. J. 
Anim. Sci. 15:523-528. 
 
Byers, F, M. 1982. Nutritional factors affecting growth of muscle and adipose tissue in 
ruminants. Fed Proc. 41:2562-2566. 
 
Calkins, C. R., and J. M. Hodgen. 2007. A fresh look at meat flavor. Meat Sci. 77:63-80. 
 
Camfield, P. K., A. H. Brown, Jr., P. K. Lewis, L. Y. Rakes, and Z. B. Johnson. 1997. Effects of 
frame size and time-on-feed on carcass characteristics, sensory attributes, and fatty acid 
profiles of steers. J. Anim. Sci. 75:1837-1844. 
 
Carroll, D. N., and M. T. Roth. 2002. Evidence for the cardioprotective effects of omega-3 fatty 
acids. Ann. Pharmacother. 36:1950-1956. 
 
Chang, K. C., N. da Costa, R. Blackley, O. Southwood, G. Evans, G. Plastow, J. D. Wood, and 
R. I. Richardson. 2003. Relationship of myosin heavy chain fibre types to meat quality 
traits in traditional and modern pigs. Meat Sci. 64:93-103. 
 
Cox, R. B., C. R. Kerth, J. G. Gentry, J. W. Prevatt, K. W. Braden, and W. R. Jones. 2006. 
Determining acceptance of domestic forage- or grain-finished beef by consumers from 
three Southeastern U. S. States. J. Food. Sci. 71:542-546. 
 
Craig, H. B., T. N. Blumer, and E. R. Barrick. 1959. Effect of several combinations of grass and 
grain in the ration of beef steers on the color characteristics of lean and fat. J. Anim. Sci. 
18:241-248. 
 
Crouse, J. D., H. R. Cross, and S. C. Seideman. 1984. Effects of a grass or grain diet on the 
quality of three beef muscles. J. Anim. Sci. 58:619-625. 
 
Davies, H. L. 1977. Continued studies on the effect of grain or pasture on the carcass 
composition and meat quality of Friesen steers. Aust. J. Agric. Res. 28:755-761. 
 
Dewhurst, R. J., N. D. Scollan, M. R. F. Lee, H. J. Ougham, and M. O. Humphreys. 2003. 
Forage breeding and management to increase the beneficial fatty acid content of ruminant 
products. Proc. Nutr. Soc. 62:329-336. 
 
Duckett, S. K., J. P. S. Neel, J. P. Fontenot, and W. M. Clapham. 2009. Effects of winter stocker 
growth rate and finishing system on: III. Tissue proximate, fatty acid, vitamin, and 
cholesterol content. J. Anim. Sci. 87:2961-2970. 
 
96 
 
Duckett, S. K., D. G. Wagner, L. D. Yates, H. G. Dolezal, and S. G. May. 1993. Effects of time 
on feed on beef nutrient composition. J. Anim. Sci. 71:2079-2088. 
 
Enser, M., K. G. Hallett, B. Hewett, G. A. J. Fursey, J. D. Wood, and G. Harrington. 1998. Fatty 
acid content and composition of UK beef and lamb muscle in relation to production 
system and implications for human nutrition. Meat Sci. 49:329-341. 
 
ERS/USDA. 2010. Livestock, dairy, and poultry outlook. 
http://www.ers.usda.gov/publications/LDP/2010/06Jun/ldpm192.pdf  . Accessed 
10/5/2010. 
 
ERS/USDA. 2009. Grain prices impact entire livestock production cycle. 
http://www.ers.usda.gov/AmberWaves/March09/PDF/GrainPrices.pdf . Accessed 
10/12/2010. 
 
ERS/USDA. 2002. Conservation and Environmental Policy: Questions and Answers. 
http://www.ers.usda.gov/Briefing/ConservationAndEnvironment/Questions/consenvaw1.
htm . Accessed 3/14/2006. 
 
Faustman, C, Q. Sun, R. Mancini, and S. P. Suman. 2010. Myoglobin and lipid oxidation 
interactions: Mechanistic bases and control. Meat Sci. 86:86-94. 
 
Faustman, C., W. K. M. Chan, D. M. Schaefer, and A. Havens. 1998. Beef color update: The role 
for vitamin E. J. Anim. Sci. 76:1019-1026. 
 
Faustman, C., and R. G. Cassens. 1990. The biochemical basis for discoloration in fresh meat: A 
review. J. Muscle Foods. 1:217-243. 
 
Fincham, J. R., J. P. Fontenot, W. S. Swecker, J. H. Herbein, J. P. S. Neel, G. Scaglia, W. M. 
Chapham,  and D. R. Notter. 2009. Fatty acid metabolism and deposition in subcutaneous 
adipose tissue of pasture- and feedlot-finished cattle. J. Anim. Sci. 87:3259-3277. 
 
Fisher, D. S., J. C. Burns, K. R. Pond, R. D. Mochrie, and D. H. Timothy. 1991. Effects of grass 
species on grazing steers: I. Diet composition and ingestive mastication. J. Anim. Sci. 
69:1188-1198. 
 
Forster, Jr.,  L. A., A. L. Goetsch, D. L. Galloway, Sr., and Z. B. Johnson. 1993. Feed intake, 
digestibility and live weight gain by cattle consuming forage supplemented with rice bran 
and (or) corn. J. Anim. Sci. 71:3105-3114. 
 
Frankel, E. N. 1980. Lipid oxidation. Prog. Lipid. Res. 19:1-22.  
 
French, P., E. G. O?Riordan, F. J. Monaham, P. J. Caffrey, M. T. Mooney, D. J. Troy, and A. P. 
Moloney. 2001. The eating quality of meat of steers fed grass and/or concentrates. Meat 
Sci. 57:379-386. 
 
97 
 
French, P., C. Stanton, F. Lawless, E. G. O?Riordan, F. J. Monahan, P. J. Caffrey, and A. P. 
Moloney. 2000. Fatty acid composition, including conjugated linoleic acid, of 
intramuscular fat from steers offered grazed grass, grass silage, or concentrate-based 
diets. J. Anim. Sci. 78:2849-2855. 
 
Galloway, Sr., D. L., A. L. Goetsch, L. A. Forster, Jr., A. C. Brake, and Z. B. Johnson. 1993. 
Digestion, feed intake, and live weight gain by cattle consuming bermudagrass and 
supplemented with different grains. J. Anim. Sci. 71:1288-1297. 
 
Gatellier, P., Y. Mercier, H. Juin, and M. Renerre. 2005. Effect of finishing mode (pasture- or 
mixed-diet) on lipid composition, colour stability and lipid oxidation in meat from 
Charolais cattle. Meat Sci. 69:175-186. 
 
Gates, R. N., P. Mislevy, and F. G. Martin. 2001. Herbage accumulation of three bahiagrass 
populations during the cool-season. Agron. Journal. 93:112-117. 
 
Geesink, G. H., S. Kuchay, A. H. Chisti, and M. Koohmaraie. 2006. ?-Calpain is essential for 
postmortem proteolysis of muscle proteins. J. Anim. Sci. 84:2834-2840. 
 
Greene, J. L., and T. H. Cumuze. 1982. Relationship between TBA numbers and 
inexperienced panelists? assessments of oxidized flavor in cooked beef. J. Food Sci. 
47:52-54. 
 
Greenwood, P. L., N. W. Tomkins, R. A. Hunter, P. G. Allingham, S. Harden, and G. S. Harper. 
2009. Bovine myofiber characteristics are influenced by postweaning nutrition. J. Anim. 
Sci. 87:3114-3123. 
 
Guenther, J. J., D. H. Bushman, L. S. Pope, and R. D. Morrison. 1965. Growth and development 
of the major carcass tissues in beef calves from weaning to slaughter weight, with 
reference to the effect of plane of nutrition. J. Anim. Sci. 24:1184-1191. 
 
Gunter, S. A., and P. A. Beck. 2004. Novel endophyte-infected tall fescue for growing beef 
cattle. J. Anim. Sci. 82: (E. Suppl.) E75-E82. 
 
Hafley, J. L. 1996. Comparison of Marshall and Surrey Ryegrass for continuous and rotational 
grazing. J. Anim. Sci. 74:2269-2275. 
 
Harfoot, C. G., and G. P. Hazelwood. 1988. Lipid Metabolism in the Rumen, Chapter 9 of The 
Rumen Microbial Ecosystem. Elsevier. New York, NY. 
 
Harrison, A. R., M. E. Smith, D. M. Allan, M. C. Hunt, C. L. Kastner, and D. H. Kropf. 1978. 
Nutritional regime effects on quality and yield characteristics of beef. J. Anim. Sci. 
47:383-388. 
 
98 
 
Hedrick, H. B., J. A. Paterson, A. G. Matches, J. D. Thomas, R. E. Morrow, W. C. Stringer, and 
R. J. Lipsey. 1983. Carcass and palatability characteristics of beef produced on pasture, 
corn silage and corn grain. J. Anim. Sci. 57:791-801. 
 
Henning, J. C., H. N. Wheaton, and C. A. Roberts. 1993. Tall fescue. University of Missouri 
Extension, G4646. 
 
Hersom, M. J., G. W. Horn, C. R. Krehbiel, and W. A. Phillips. 2004. Effect of live weight gain 
of steers during winter grazing: I. Feedlot performance, carcass characteristics, and body 
composition of beef steers. J. Anim. Sci. 262-272. 
 
Hill, G. M., R. N. Gates, and G. W. Burton. 1993. Forage quality and grazing steer performance 
from Tifton 85 and Tifton 78 bermudagrass pastures. J. Anim. Sci. 71:3219-3225. 
 
Hopkins, D. J., and J. M. Thompson. 2002. Factors contributing to proteolysis and disruption of 
myofibrillar proteins and the impact on tenderization in beef and sheep meat. Aust. J. 
Agric. Res. 53:149-166. 
 
Howard, M. D., R. B. Muntifering, N. W. Bradley, G. E. Mitchell, Jr., and S. R. Lowry. 1992. 
Voluntary intake and ingestive behavior of steers grazing Johnstone or endophyte-
infected Kentucky-31 tall fescue. J. Anim. Sci. 70:1227-1237. 
 
Huff-Lonergan, E., W. Zhang, and S. M. Lonergan. 2010. Biochemistry of postmortem muscle-
Lessons on mechanisms of meat tenderization. Meat Sci. 86:184-195. 
 
Huff-Lonergan, E., and S. M. Lonergan. 2005. Mechanism of water-holding capacity of meat: 
The role of postmortem biochemical and structural changes. Meat Sci. 71:194-204. 
 
Jennings, T. G., B. W. Berry, and A. L. Joseph. 1978. Influence of fat thickness, marbling and 
length of aging on beef palatability and shelf-life characteristics. J. Anim. Sci. 46:658-
665. 
 
Johnston, D. M., D. F. Stewart, W. G. Moody, J. Boling, and J. D. Kemp. 1975. Effect of breed 
and time on feed on the size distribution of beef muscle fiber types. J. Anim. Sci. 40:613-
620. 
 
Karlsson, A., A. Enf?lt, B. Ess?n-Gustavsson, K. Lundstr?m, L. Rydhmer and S. Stern. 1993. 
Muscle histochemical and biochemical properties in relation to meat quality during 
selection for increased lean tissue growth rate in pigs. J. Anim. Sci. 71:930-938. 
 
 
Kerth, C. R., K. W. Braden, R. Cox, L. K. Kerth, and D. L. Rankins, Jr. 2007. Carcass, sensory, 
fat color, and consumer acceptance characteristics of Angus-cross steers finished on 
ryegrass (Lolium multiflorum) forage or on a high-concentrate diet. Meat Sci. 75:324-
331. 
 
99 
 
Kerth, C. R., L. K. Blair-Kerth, and W. R. Jones. 2003. Warner-Bratzler shear force repeatability 
in beef longissimus steaks cooked with a convestion oven, broiler, or clam-shell grill. J. 
Food Sci. 68:668-670. 
 
Killinger, K. M., C. R. Calkins, W. J. Umberger, D. M. Feuz, and K. M. Eskridge. 2004. 
Consumer sensory acceptance and value for beef steaks of similar tenderness, but 
differing in marbling level. J. Anim. Sci. 82:3294-3301. 
 
King, D. A., T. L. Wheeler, S. D. Shackelford, K. D. Pfeiffer, R. Nickelson, and M. Koohmaraie. 
2009. Effect of blade tenderization, aging time, and aging temperature on tenderness of 
beef longissimus lumborum and gluteus medius. J. Anim. Sci. 87:2952-2960. 
 
Kirchofer, K. S., C. R. Calkins, and B. L. Gwartney. 2002. Fiber-type composition of muscles of 
the beef chuck and round. J. Anim. Sci. 80:2872-2878. 
 
Klont, R. E., L. Brocks, and G. Eikelenboom. 1998. Muscle fibre type and meat quality. Meat 
Sci. 49: suppl. 1, S229-S229. 
 
Koch, R. M., L. V. Cundiff, and K. E. Gregory. 1982. Heritabilities and genetic, environmental 
and phenotypic correlation of carcass traits in a population of diverse biological types and 
their implications in selection programs. J. Anim. Sci. 55:1319-1329. 
 
Koger, T. J., D. M. Wulf, A. D. Weaver, C. L. Wright, K. E. Tjardes, K. S. Mateo, T. E. Engle, r. 
J.  Maddock, and A. J. Smart. 2010. Influence of feeding various quantities of wet and 
dry distillers grains to finishing steers on carcass characteristics, meat quality, retail-case 
life of ground beef, and fatty acid profile of longissimus muscle.  J. Anim. Sci. 88:3399-
3408. 
 
Koohmaraie, M. 1992. Effect of pH, temperature, and inhibitors on autolysis and catalytic 
activity of bovine skeletal muscle ?-calpain. J. Anim. Sci. 70:3071-3080. 
 
Kropf, D. H. 1980. Effects of retail display conditions on meat color. Proceedings from the 33rd 
Reciprocal Meats Conference, West Lafayette, IN. 
 
Laborde, F. L., I. B. Mandell, J. J. Tosh, J. W. Wilton, and J. G. Buchanan-Smith. 2001. Breed 
effects on growth performance, carcass characteristics, fatty acid composition, and 
palatability attributes in finishing steers. J. Anim. Sci. 79:355-365. 
 
Lanari, M. C., D. M. Schaefer, Q. Liu, and R. G. Cassens. 1996. Kinetics of pigment oxidation in 
beef from steers supplemented with vitamin E. J. Food Sci. 61:884-889. 
 
Leander, R. C., H. B. Hedrick, W. C. Stringer, J. C. Clark, G. B. Thompson, and A. G. Matches. 
1978. Characteristics of bovine longissimus and semitendinosus muscles from grass and 
grain-fed animals. J. Anim. Sci. 46:965-970. 
 
100 
 
Lee, S. H., S. T. Joo, and Y. C. Ryu. 2010. Skeletal muscle fiber type and myofibrillar proteins 
in relation to meat quality. Meat Sci. 86:166-170. 
 
Lefaucheur, L, and D. Gerrard. 1998. Muscle fiber plasticity in farm mammals. Proceedings of 
the American Society of Animal Science.  
 
Leheska, J. M., L. D. Thompson, J. C. Howe, E. Hentges, J. Boyce, J. C. Brooks, B. Shriver, L. 
Hoover, and M. F. Miller. 2008. Effects of conventional and grass-feeding systems on the 
nutrient composition of beef. J. Anim. Sci. 86:3575-3585. 
 
Lund, M. N., R. Lametsch, M. S. Hviid, O. N. Jensen, and L. H. Skibsted. 2007. High-oxygen 
packaging atmosphere influences protein oxidation and tenderness of porcine longissimus 
dorsi during chill storage. Meat Sci. 77:295-303. 
 
Maheca, L., K. Nuernberg, G. Nuernberg, K. Ender, E. Hagemann, and D. Danneberger. 2009. 
Effects of diet and storage on fatty acid profile, micronutrients and quality of muscle 
from German Simmental bulls. Meat Sci. 82:365-371. 
 
Malinowski, D. P., H. Zuo, B. A. Kramp, J. P. Muir, and W. E. Pincak. 2005. Obligatory 
summer-dormant cool-seaosn perennial grasses for semiarid environments of the 
southern Great Plains. Agron. Journal. 97:147-154. 
 
Mancini, R. A., and M. C. Hunt. 2005. Current research in meat color. Meat Sci. 71: 100-121. 
 
Mandell, I. B., J. G. Buchanan-Smith, and C. P. Campbell. 1998. Effects of forage vs. grain 
feeding on carcass characteristics, fatty acid composition, and beef quality in Limousin-
cross steers when time on feed is controlled. J. Anim. Sci. 76:2619-2630. 
 
May, S. G., H. G. Dolezal, D. R. Gill, F. K. Ray, and D. Buchanan. 1992. Effect of days fed, 
carcass grade traits, and subcutaneous fat removal on postmortem muscle characteristics 
and beef palatability. J. Anim. Sci. 70:444-453. 
 
May, M. L., M. E. Dikeman, and R. Schalles. 1977. Longissimus muscle histological 
characteristics of Simmental x Angus, Hereford x Angus, and Limousin x Angus 
crossbred steers as related to carcass composition and meat palatability traits. J. Anim. 
Sci. 44:571-580. 
 
Melton, S. L. 1990. Effects of feeds on flavor of red meat: A review. J. Anim. Sci. 68:4421-
4435. 
 
Mercier, Y., P. Gatellier, and M. Renerre. 2004. Lipid and protein oxidation in vitro, and 
antioxidant potential in meat from Charolais cows finished on pasture or mixed diet. 
Meat Sci. 66:467-473. 
 
Mitchell, G. E., A. W. Reed, and S. A. Rogers. 1991. Influence of feeding regimen on the 
sensory qualities and fatty acid contents of beef steaks. J. Food Sci. 56:1102-1103. 
101 
 
 
Muir, P. D., J. M. Deaker, and M. D. Bown. 1998. Effects of forage- and grain-based feeding 
systems on beef quality: A review. New Zealand J. Agric. Res. 41:623-635. 
 
Muir, P. D., N. B. Smith, G. J. Wallace, G. J. Cruickshank, and D. R. Smith. 1998. The effect of 
short-term grain feeding on liveweight gain and beef quality. New Zealand J. Agric. Res. 
41:517-526. 
 
NCBA. 2010. Cattle Industry History. http://www.beefusa.org/theicattleindustryhistory.aspx . 
Accessed 10/20/2010. 
 
Neel, J. P. S., J. P. Fontenot, W. M. Clapham, S. K. Duckett, E. E. D. Felton, G. Scaglia, and W. 
B. Bryan. 2007. Effects of winter stocker growth rate and finishing system on: I. Animal 
performance and carcass characteristics. J. Anim. Sci. 85:2012-2018. 
 
Noci, F., F. J. Monahan, P. French, and A. P. Moloney. The fatty acid composition of muscle fat 
and subcutaneous adipose tissue of pasture-fed beef heifers: Influence of the duration of 
grazing. J. Anim. Sci. 83:1167-1178. 
 
Norman, J. L., E. P. Berg, M. R. Ellersieck, and C. L. Lorenzen. 2004. Prediction of color and 
pH measurement throughout boneless center-cut pork loins. Meat Sci. 66:273-278. 
 
Nuernberg, K., D. Dannenberger, G. Nuernberg, K. Ender, J. Voigt, N. D. Scollan,J. D. Wood, g. 
R. Nute, and R. I. Richardson. 2005. Effect of a grass-based and a concentrate feeding 
system on meat quality characteristics and fatty acid composition of longissimus muscle 
in different cattle breeds. Livestock Prod. Sci. 94:137-147. 
 
Ockerman, H. W., D. Jaworek, B. VanStavern, N. Parrett, and C. J. Pierson. 1984. Castration and 
sire effects on carcass traits, meat palatability and muscle fiber characteristics in Angus 
cattle. J. Anim. Sci. 59:981-990. 
 
O?Fallon, J. V., J. R. Busboom, M. L. Nelson, and C. T. Gaskins. 2007. A direct method for fatty 
acid methyl ester synthesis: Application to wet meat tissues, oils, and feedstuffs. J. Anim. 
Sci. 85:1511-1521. 
 
O?Sullivan, A., K. O?Sullivan, K. Galvin, A. P. Moloney, D. J. Troy, and J. P. Kerry. 2004. 
Influence of concentrate composition and forage type on retail packaged beef quality. J. 
Anim. Sci. 82:2384-2391. 
 
Page, J. K., D. M. Wulf, and T. R. Schwotzer. 2001. A survey of beef muscle color and pH. J. 
Anim. Sci. 79:678-687. 
 
Picard, B., L. Lefaucheur, C. Berri, and M. J. Duclos. 2002. Muscle fibre ontogenesis in farm 
animal species. Reprod. Nutr. Dev. 42:415-431. 
 
102 
 
Poulson, C. S., T. R. Dhiman, A. L. Ure, D. Cornforth, and K. C. Olson. 2004. Conjugated 
linoleic acid content of beef from cattle fed diets containing high grain, CLA, or raised on 
forages. Liv. Prod. Sci. 91:117-128. 
 
Priolo, A., D. Micol, and J. Agabriel. 2001. Effects of grass feeding systems on ruminant meat 
colour and flavour. A review. Anim. Res. 50:185-200. 
 
Purchas, R. W., and H. L. Davies. 1974. Carcass and meat quality of Friesian steers fed on either 
pasture or barley. Aust. J. Agric. Res. 25:183-192. 
 
Reagan, J. O., J. A. Carpenter, F. T. Bauer, and R. S. Lowrey. 1977. Packaging and palatability 
characteristics of grass and grass-grain fed beef. J. Anim. Sci. 46:716-721. 
 
Realini, C. E., S. K. Duckett, N. S. Hill, C. S. Howeland, B. G. Lyon, J. R. Sackmann, and M. H. 
Gillis. 2005. Effect of endophyte type on carcass traits, meat quality, and fatty acid 
composition of beef cattle grazing tall fescue. J. Anim. Sci. 83:430-439. 
 
Realini, C. E., S. K. Duckett, G. W. Brito, M. Dalla Rizza, and D. De Mattos. 2004. Effect of 
pasture vs. concentrate feeding with or without antioxidants on carcass characteristics, 
fatty acid composition, and quality of Uruguayan beef. Meat Sci. 66:567-577. 
 
Reuter, R. R., and G. W. Horn. 2002. Cool-season perennial grasses as complementary forages to 
winter wheat pasture. The Prof. Anim. Sci. 18:44-51. 
 
Rhee, K. S., and C. E. Myers. 2003. Sensory properties and lipid oxidation in aerobically 
refrigerated cooked ground goat meat. Meat Sci. 189-194. 
 
Roberts, S. D., C. R. Kerth, K. W. Braden, D. L. Rankins, Jr., L. Kriese-Anderson, and J. W. 
Prevatt. 2009. Finishing steers on winter annual ryegrass (Lolium multiflorum Lam.) with 
varied levels of corn supplementation I: Effects on animal performance, carcass traits, 
and forage quality. J. Anim. Sci. 87:2690-2699. 
 
Rowe, C. W., F. W. Pohlman, A. H. Brown, Jr., Z. B. Johnson, S. H. Whiting, and D. L. 
Galloway. 2009. Effects of conjugated linoleic acid, salt, and sodium tripolyphosphate on 
physical, sensory, and instrumental color characteristics of beef striploins. J. Food Sci. 
74:36-43. 
 
Rowe, L. J., K. R. Maddock, S. M. Lonergan, and E. Huff-Lonergan. 2004. Oxidative 
environments decrease tenderization of beef steaks through inactivation of ?-calpains. J. 
Anim. Sci. 82:3254-3266. 
 
Ryu, Y. C. and B. C. Kim. 2005. The relationship between muscle fiber characteristics, 
postmortem metabolic rate and meat quality of pig longissimus dorsi muscle. Meat Sci. 
351-357. 
 
103 
 
Sapp, P. H., S. E. Williams, and M. A. McCann. 1999. Sensory attributes and retail display 
characteristics of pasture- and/or grain-fed beef aged 7, 14 or 21 days. J. Food Qual. 
22:257-274. 
 
Sawyer, J. T., J. K. Apple, and Z. B. Johnson. 2008. The impact of lactic acid concentration and 
sodium chloride on pH, water-holding capacity, and cooked color of injection-enhanced 
dark-cutting beef. Meat Sci. 79:317-325. 
 
Sayre, L. M., D. Lin, Q. Yuan, X. Zhu, and X. Tang. 2006. Protein adducts generated from 
products of lipid oxidation: Focus on HNE and ONE. Drug Metabolism Reviews. 38:651-
675.  
 
Schaake, S. L., G. C. Skelley, E. Halpin, L. W. Grimes, R. B. Brown, D. L. Cross, and C. E.  
Thompson. 1993. Carcass and meat sensory traits of steers finished on fescue and clover, 
summer forage or for different periods in drylot. J. Anim. Sci. 71:3199-3205. 
 
Schroeder, J. W., D. A. Cramer, R. A. Bowling, and C. W. Cook. 1980. Palatability, shelf-life 
and chemical differences between forage- and grain-finished beef. J. Anim. Sci. 50:852-
859. 
 
Schupp, A. R., T. D. Bidner, and N. C. Clark. 1980. Consumer acceptance of beef produced 
under alternative feeding systems. So. J. Agric. Econ. 12:31-35. 
 
Seideman, S. C., J. D. Crouse, and H. R. Cross. 1982. Effect of feeding regimen and vacuum-
packaged storage on sensory and physical properties of beef steaks. J. Food Protection. 
45: 1227-1231. 
 
Shanks, B. C. D. M. Wulf, and R. J. Maddock. 2002. Technical note: The effect of freezing on 
Warner-Bratzler shear force values of beef longissimus steaks across several postmortem 
aging periods. J. Anim. Sci. 80:2122-2125. 
 
Simopoulos, A.P. 2002. The importance of the ratio of omega-6/ omega-3 essential fatty acids. 
Biomed Pharmacother. 56: 365-379. 
 
Sitz, B. M., C. R. Calkins, D. M. Feuz, W. J. Umberger, and K. M. Eskridge. 2005. Consumer 
and sensory acceptance and value of domestic, Canadian, and Australian grass-fed beef 
steaks. J. Anim. Sci. 83:2863-2868. 
 
Solomon, M. B., and M. C. Dunn. 1988. Simultaneous histochemical determination of 3 fiber 
types in single sections of ovine, bovine, and porcine skeletal muscle. J. Anim. Sci. 
66:255-264. 
 
Sprecher, H. 2000. Metabolism of highly unsaturated n-3 and n-6 fatty acids. Biochimica et 
Biophysica. 1486:219-231. 
 
104 
 
Srinivasan, S., Y. L. Xiong, and E. A. Decker. 1996. Inhibition of protein and lipid oxidation in 
beef heart surimi-like material by antioxidants and combinations of pH, NaCl, and buffer 
type in the washing media. J. Agric. Food Chem. 44:119-125. 
 
Steen, R. W., N. P. Lavery, D. J. Kirkpatrick and M. G. Porter. 2003. Effects of pasture and 
high-concentrate diets on the performance of beef cattle, carcass composition at equal 
growth rates, and the fatty acid composition of beef. New Zealand J. of Agricultural 
Research. 46: 69-81. 
 
Steen, R. W. J., and D. J. Kilpatrick. 2000. The effects of the ratio of grass silage to concentrates 
in the diet and restricted dry matter intake on the performance and carcass characteristics 
of beef cattle. Livestock Prod. Sci. 62:181-192. 
 
Stivarius, M. R., F. W. Pohlman, K. S. McElyea, and J. K. Apple. 2002. The effects of acetic 
acid, gluconic acid and trisodium citrate treatment of beef trimmings on microbial, color 
and odor characteristics of ground beef through simulated retail display. Meat Sci. 
60:245-252. 
 
Strydom, P. E., L. Frylinck, J. L. Montgomery, and M. F. Smith. 2009. The comparison of three 
?-agonists for growth performance, carcass characteristics and meat quality of feedlot 
cattle. Meat Sci. 557-564. 
 
Taliaferro, C. M., F. P. Horn, B. B. Tucker, R. Totusek, and R. D. Morrison. 1974. Performance 
of three warm-season perennial grasses and a native range mixture as influenced by N 
and P fertilization. Agron. Journal. 67:289-292. 
 
Therkildsen, M., L. Melchior Larsen, H. G. Bang, and M. Vestergaard. 2002a. Effect of growth 
rate on tenderness development and final tenderness of meat from Friesian calves. Anim. 
Sci. 74:253-264. 
 
Therkildsen, M., L. Melchior Larsen, and M. Vestergaard. 2002b. Influence of growth rate and 
muscle type on muscle fibre type characteristics, protein synthesis capacity and activity 
of the calpain system in Friesen calves. Animal Sci. 74:243-251. 
 
Therkildsen, M., M. Vestergaard, L. R. Jensen, H. R. Andersen, and K. Sejrsen. 1998. Effect of 
feeding level, grazing and finishing on growth and carcass quality of young Friesian 
bulls. Acta Agric. Scand. Sect. A. Animal Sci. 48:193-201. 
 
Thompson, F. N., J. A. Stuedemann, and N. S. Hill. 2001. Anti-quality factors associated with 
alkaloids in eastern temperate pasture. J. Range Manage. 54:474-489. 
 
Umberger, W. J., D. M. Feuz, C. R. Calkins, and K. Killinger-Mann. 2002. U.S. Consumer 
preference and willingness-to-pay for domestic corn-fed beef versus International grass-
fed beef measured through an experimental auction. Agribusiness. 18:491-504. 
 
105 
 
University of California Sustainable Agriculture Research & Education Program. 2002. 
http://www.sarep.ucdavis.edu. Accessed 10/25/2005. 
 
USDA. 2007. National Agriculture Statistics Service, Census of Agriculture. 
http://www.agcensus.usda.gov/Publications/2007/Full_Report/usv1.pdf . Accessed 
11/08/2010. 
 
USDA. 1997. United States standards for grades of carcass beef. United States Department of 
Agriculture, Agricultural Marketing Service, Livestock and Seed Division. 
 
Varela, A., B. Oliete, T. Moreno, C. Portela, L. Monserrrat, J. A. Carballo, and L. S?nchez. 
2004. Effect of pasture finishing on the meat characteristics and intramuscular fatty acid 
profile of steers of the Rubia Gallega breed. Meat Sci. 67:515-522. 
 
Vestergaard, M., N. Oksberg, and P. Henckel. 2000a. Influence of feeding intensity, grazing and 
finishing feeding on muscle fiber characteristics and meat colour of semitendinosues, 
longissimus dorsi and supraspinatus muscles of young bulls. Meat Sci. 54:177-185. 
 
Vestergaard, M., M. Therkildsen, P. Henckel, L. R. Jensen, H. R. Andersen, and K. Sejrsen. 
2000b. Influence of feeding intensity, grazing and finishing on meat and eating quality of 
young bulls and the relationship between muscle fibre characteristics, fibre fragmentation 
and meat tenderness. Meat Sci. 54:187-195. 
 
Viljanen, K., P. Kylli, R. Kivikari, and M. Heinonen. 2004. Inhibition of protein and lipid 
oxidation in liposomes by berry phenolics. J. Agric. Food Chem. 52:7419-7424. 
 
Wachira, A. M., L. A. Sinclair, R. G. Wilkison, K. Hallett, M. Enser, and J. D. Wood. 2000. 
Rumen biohydrogenation of n-3 polyunsaturated fatty acids and their effects on microbial 
efficiency and nutrient digestibility in sheep. J. Ag. Sci. 135:419-428.  
 
Wang, B., R. D. Pace, A. P. Dessai, A. Bovell-Benjamin, and B. Phillips. 2002. Modified 
extraction method for determining 2-thiobarbituric acid values in meat with increase 
specificity and simplicity. J. Food Sci. 67:2833-2836. 
 
Ward, C. E., and T. C. Schroeder.  2004. Structural changes in cattle feeding and meat packing. 
Cooperative Extension Fact Sheet F-553. Stillwater, Okla.: Oklahoma State University. 
 
 
 
Warren, H. E., N. D. Scollan, M. Enser, S. I. Hughes, R. I. Richardson, and J. D. Wood. 2008. 
Effects of breed and a concentrate or grass silage diet on beef quality in cattle of 3 ages. 
I: Animal performance, carcass quality and muscle fatty acid composition. Meat Sci. 
78:256-269. 
 
Webb, E. C., and H. A. O?Neill. 2008. The animal fat paradox and meat quality. Meat Sci. 
80:28-36. 
106 
 
 
Wegner, J., E. Albrecht, I. Fiedler, F. Teuscher, H.-J. Papstein, and K. Ender. 2000. Growth- and 
breed-related changes of muscle fiber characteristics in cattle. J. Anim. Sci. 78:1485-
1496. 
 
Westerling, D. B. and H. B. Hedrick. 1979. Fatty acid composition of bovine lipids as influenced 
by diet, sex and anatomical location and relationship to sensory characteristics. J. Anim. 
Sci. 48:1343-1348. 
 
Wheeler, T. L., S. D. Shackelford, and M. Koohmaraie. 1996. Sampling, cooking, and coring 
effects on Warner-Bratzler shear force values in beef. J. Anim. Sci. 74:1553-1562. 
 
Wheeler, T. L., J. W. Savell, H. R. Cross, D. K. Lunt, and S. B. Smith. 1990. Mechanisms 
associated with the variation in tenderness of meat from Brahman and Hereford cattle. J. 
Anim. Sci. 68:4206-4220. 
 
Whipple, G., M. Koohmaraie, M. E. Dikeman, and J. D. Crouse. 1990. Predicting beef-
longissimus tenderness from various biochemical and histological muscle traits. J. Anim. 
Sci. 68:4193-4199. 
 
Winchester, C. F. 1964. Symposium on growth: Environment and growth. J Anim. Sci. 23:254-
264. 
 
Wood, J. D., M. Enser, A. V. Fisher, G. R. Nute, P. R. Sheard, R. I. Richardson, S. L. Hughes,  
and F. M. Whittington. 2008. Fat deposition, fatty acid composition and meat quality: A 
review. Meat Sci. 78:343-358. 
 
Wood, J. D., and M. Enser. 1997. Factors influencing fatty acids in meat and the role of 
antioxidants in improving meat quality. British J. of Nutr. 78. Suppl. 1, S49-S60. 
 
Xiong, Y. L., W. G. Moody, S. P. Blanchard, G. Liu, and W. R. Burris. 1996. Postmortem 
proteolytic and organoleptic changes in hot-boned muscle from grass- and grain-fed and 
zeranol-implanted cattle. Food Res. International. 29:27-34. 
 
Yancey, J. W. S., and D. H. Kropf. 2008. Instrumental reflectance values of fresh pork are 
dependent on aperture size. Meat Sci. 79:734-739. 
 
Yang, A., M. C. Lanari, M. Brewster, and R. K. Tume. 2002. Lipid stability and meat colour of 
beef from pasture- and grain-fed cattle with or without vitamin E supplement. Meat Sci. 
60:41-50. 
 
Yang, A., T. W. Larsen, and R. K. Tume. 1992. Carotenoid and retinol concentrations in serum, 
adipose tissue and liver and carotenoid transport in sheep, goats, and catle. Aust. J. Agric. 
Res. 43:1809-1817. 
107 
 
Appendices 
 
108 
 
Appendix A 
Histochemical Fiber type analyses 
 
Reference 
Solomon, M. B., and Dunn, M. C. 1988. Simultaneous histochemical determination of 3 fiber 
types in single sections of ovine, bovine, and porcine skeletal muscle. J. Anim. Sci. 66:255-264. 
 
A. Solutions 
 a. Acid Pre-incubation solution 
  100 mL CaCl2 (0.18 M) 
  3 mL Glacial Acetic Acid 
  890 mL ddH2O 
  Adjust pH to 4.15   Note: Even though the pH is adjusted at this  
       step it will need to be adjusted again  
       depending on the species being typed 
 b. Rinse 
  12.1 g Tris Base 
  100 mL CaCl2  (0.18 M) 
  900 mL ddH2O 
  Adjust pH to 7.8 
 
 c. ATPase Incubation Medium: (Make fresh immediately before use) 
  40 mL Batch      200 mL Batch 
  2.68 mL 2-Amino 2-Methyl 1-Propanol (1.5 M) 13.40 mL 
  4.0 mL CaCl2      20.00 mL 
  0.148 g KCL      0.740 g 
  0.0608 g ATP      0.304 g 
  32.0 mL ddH2O     160.00 mL 
  (QS to 40 mL)      (QS to 200 mL) 
 
  Adjust pH to 9.4; incubate tissues to 37o C 
 
 d. ?-NADH Incubation Solution  **(Make fresh daily)** 
  10 mL 0.2 M Tris Buffer, pH 7.4 
  10 mg Tetranitro Blue Tetrazolium (TNBT) 
  8 mg Nicotineamide Adenine Dinucleotide, reduced 
 
Note: No matter how long you mix this it will not all go into solution, therefore, it 
MUST BE FILTERED 
 
 e. Tris Buffer, pH 7.4 
  75 mL 0.2 M Tris Base (12.11 g / 500 mL) 
  126 mL 0.1 M HCL (50 mL of 1 N HCL, QS to 500 mL) 
    **(1 N HCL is 41.7 mL HCL / 458 mL ddH2O)** 
109 
 
  174 mL ddH2O 
  As a preservative, add a few drops of Chloroform 
 
 f. Ehrlich?s Hematoxylin Stain 
  6 g hematoxylin 
  300 mL ethyl alcohol, absolute 
  9 g Aluminum Ammonium Sulfate 
  300 mL ddH2O 
  300 mL Glycerin (Glycerol) 
  0.72 g Sodium Iodate 
  30 mL Glacial Acetic Acid 
  Mix and Filter 
 
 g. 0.18 M CaCl2 = 26.46 g / L of ddH2O 
 
 h. 1% (w/v) CaCl2 = 10 g / L ddH2O 
 
 i. 2% CoCl2 (w/v) = 10 g / 500 mL ddH2O 
 
 j. 2% (v/v) Ammonium Sulfide (Mix under hood)  10 mL / 500 mL ddH2O 
 
 k. 50% (v/v) Ethyl Alcohol = 250 mL EA / 250 mL ddH2O 
 
 l. Glycerol Gelatin/Flouromount 
 
 
B. Sample preparation 
 
 a. Cut section of muscle transverse to fiber orientation to approximately 1 inch thick.  Cut 
sample parallel to fiber orientation to approximately 0.65 cm x 0.65 cm x 2 cm.  Then freeze in 
isopentane chilled in liquid nitrogen.  Place sample in whirl pac bags. 
 
 b. After placing in whirl pac bags, place whirl pac bag in vacuum bag and vacuum 
package.  Keep frozen and store at -80o C. 
 
 c. Upon time of analysis, remove sample from ultracold and place in cryostat.  Set 
cryostat to -20o C and cut thickness to 10?m.  Fix samples to cork board with freezing media and 
make sure that fibers are perpendicular to cork board. 
 
 d. Freeze cork board to the chuck in the cryostat using freezing media.   
 
 e. After freezing is finished, place chuck in cryostat arm and slice the sample until the 
whole cross section of the sample is exposed.  Slice a section and affix to slide.  Repeat 4 to 6 as 
needed. 
 
C. Staining Sequence for Bovine 
110 
 
a. Start solutions that need to made or pH adjusted 
b. Turn on oven to 37oC 
c. Cut slices for slides 
d. ?-NADH solution, drop on slides, incubate for 45 min @ 37oC 
e. Drop distilled water on slide, let stand for 30 sec. 
f. Drop acid preincubation solution on slide, let stand at room temp for 10 min. 
g. Drop rinse solution on slide for 1 min. pH 7.8 
h. Repeat step 7 
i. Drop ATPase incubation solution on slide, pH 9.4, incubate @ 37oC for 30 min. 
j. Drop 1% CaCl2 on slide, let stand for 30 sec. 
k. Repeat step 10. 
l. Repeat step 10  
m. Drop 2% CaCl2 on slide, let stand for 3 min. 
n. Drop distilled water on slide, let stand for 30 sec. 
o. Repeat step 14 
p. Repeat step 14 
q. Repeat step 14 
r. Drop 2% Ammonium sulfide on slide, DO THIS UNDER HOOD, let stand for 3 min. 
s. Place slides into container, run distilled water continuously for 3 min. 
t. Place slides in hematoxylin for 5 min 
u. Repeat step 19 
v. Place slides in 50% EtOH for 2 min. 
w. Drain and mount slides with gel and place cover slip on them. 
x. Let stand for a while before handling and viewing.  
 
Results: 
 ?-Red fibers:  Fibers that stain dark purple 
 ?-Red fibers:  Fibers that stain intermediate 
 ?-White Fibers: Fibers that stain light purple 
 
Note: 
 - For "cleaner" slides, filter the NADH solution before using it 
- If three fiber types are not identifiable, increase the pH of the acid preincubation step 
until desired intensity is obtained 
 
 
 
 
 
 
 
111 
 
Appendix B 
Sensory Evaluation form 
 
Trained Sensory Evaluation Form 
 
 
Name_____________________ 
 
Date__________________ Time_____________________ Project_________________ 
Sample No Initial Juiciness Sustained Juiciness Initial Tenderness Sustained Tenderness Flavor Intensity Off Flavor Off Descriptor 
1 
       
2 
       
3 
       
4 
       
5 
       
6 
       
7 
       
8 
       
9 
       
10 
       
11 
       
12 
       
Juiciness Tenderness Flavor Intensity Off Flavor Off Flavor Descriptors 
8=Extremely Juicy 
 
7=Very Juicy 
 
6=Moderately Juicy 
 
5=Slightly Juicy 
 
4=Slightly Dry 
 
3=Moderately Dry 
 
2=Very Dry 
 
1=Extremely Dry 
8=Extremely Tender 
 
7=Very Tender 
 
6=Moderately Tender 
 
5=Slightly Tender 
 
4=Slightly Tough 
 
3=Moderately Tough 
 
2=Very Tough 
 
1=Extremely Tough 
8=Extremely Intense Beef 
 
7=Very Intense Beef 
 
6=Moderately Intense Beef 
 
5=Slightly Intense Beef 
 
4=Slightly Bland 
 
3=Moderately Bland 
 
2=Very Bland 
 
1=Extreme Bland 
8=Extreme Off Flavor 
 
7=Intense Off Flavor 
 
6=Very Off Flavor 
 
5=Moderate Off Flavor 
 
4=Modest Off Flavor 
 
3=Small Off Flavor 
 
2=Slight Off Flavor 
 
1=No Off Flavor 
8=Metallic 
 
7=Salty 
 
6=Livery 
 
5=Grassy 
 
4=Bitter 
 
3=Bloody 
 
2=Rancid 
 
1=Other-Explain 
112 
 
Appendix C 
Thiobarbituric Reactive Substances Assay 
 
Reference 
Wang, B., Pace, R. D., Dessai, A. P., Bovell-Benjamin, A., Phillips, B. 2002. Modified 
extraction method for determining 2-thiobarbituric acid values in meat with increase specificity 
and simplicity. J. Food Sci. 67:2833-2836. 
 
A. Solutions 
 a. TCA Extraction solution 
  7.5% (w/v) trichloroacetic acid 
  0.1% (w/v) EDTA 
  0.1% (w/v) Propyl Gallate 
 
 b. 80 mM TBA solution 
  1.15 g Thiobarbituric acid into 100 mL ddH2O 
 
 c. Standard Solution 
  Make a 1 mM solution by adding 240 ?L of tetraethoxypropane to 1L 
B. Standards 
 a. Dilute 1mM stock solution to 80 nM /L  
 
 b. Then make standards following the table below in individual tubes 
 
mg / kg TEP TEP (?L)  TCA (?L)  Pipette Setting  
0  0  2000  1000 x 2  
2  50  1950  975 x 2  
4  100  1900  950 x 2  
6  150  1850  925 x 2  
8  200  1800  900 x 2  
10  250  1750  875 x 2  
20  500  1500  750 x 2  
30  750  1250  625 x 2  
 
 
C. Sample preparation and extraction procedure 
 a. Mince meat sample and weigh out 5 g  
  
 b. Place meat into a 50 mL centrifuge tube and add 15 mL TCA Extraction solution 
 
 c. Homogenize meat for 20-30 sec using a blender 
 
 d. Place lid back on centrifuge tube  
 
113 
 
 e. Centrifuge at 1,500 x g for 15 min 
 
 f. Remove from centrifuge and filter through No. 4 Whatman paper 
 
D. Incubation and Reading 
 a. Load 96-well microplate  
 
 b. Each sample should be loaded in triplicate with 125 ?L / well (See diagram below for 
details 
 
 1 2 3 4 5 6 7 8 9 10 11 12 
A 0 0 0  A A A I I I Q Q Q 
B 2 2 2 B B B J J J R R R 
C 4 4 4 C C C K K K S S S 
D 6 6 6 D D D L L L T T T 
E 8 8 8 E E E M M M U U U 
F 10 10 10 F F F N N N V V V 
G 20 20 20 G G G O O O W W W 
H 30 30 30 H H H P P P X X X 
 
 c. After sample are loaded, pipette 125 ?L of TBA Solution into each well  
 
 d. Incubate for 130 min at 40o C  
 
 e. Remove plates from incubator and read at 540 nm on plate reader 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
114 
 
Appendix D 
Fatty Acid Methyl Esters 
 
Reference 
 
O?Fallon, J. V., Busboom, J. R., Nelson, M. L., Gaskins, C. T. 2007. A direct method for fatty 
acid methyl ester synthesis: Application to wet meat tissues, oils, and feedstuffs. J. Anim. Sci. 
85:1511-1521. 
 
A. Solutions and Chemicals 
 a. Hexane 
 
 b. Methanol (MeOH) 
 
 c. 10 N KOH 
 
 d. 24 N H2SO4 
 
B. Direct Fatty Acid Methylation 
 a. Mince meat sample and weigh out 1 g 
 
 b. Place 1 g meat into a 16 mL screwtop tube 
 
 c. Add 5.3 mL of MeOH, 0.7 mL of KOH and standard to meat sample in tube.  Place cap 
on tube and place in water bath at 55o C.  If waterbath has a shaker attachment, turn shaker 
attachment on to desired setting.  If there is no shaker attachment, vortex samples for 5 s every 
20 min.  Incubate for 90 min. 
 
 d. After incubation, place samples in cold tap water and allow to cool to below room 
temperature. 
 
 e. After cooling, add 0.58 mL of 24 N H2SO4.  Mix tube by inversion and make sure 
K2SO4 precipitate is present.  Place tube back in water bath and incubate for 90 min at 55o C.  If 
there is no shaker attachment, vortex samples for 5 s every 20 min. 
 
 f. Repeat step d. 
 
 g. After cooling, add 3 mL of hexane and vortex for 5 min. 
 
 h. Centrifuge tubes for 5 min at 1,500 x g. 
 
 i. Remove hexane layer and place in fatty acid vial. 
 
 j. Place fatty acid vials in freezer until time of analysis