Forage Type Effects on Beef Cattle Performance and Carcass Traits
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Non-implanted Angus crossbred steers from Auburn University’s Wiregrass Research and Extension Center resident herd in Headland, Alabama were used for a two-year forage-finishing study. In January 2006 (n = 18) and December 2006 (n = 18) steers were randomly assigned a forage treatment. Steers (n = 3) were grazed on duplicate 1. 42 ha paddocks of Wren’s Abruzzi Rye (Secale cereale L.), Harrison Oats (Avena sativa L.), or Marshall Ryegrass (Lolium multiflorum Lamarck). Pen served as experimental unit for the project. The steers were humanely harvested after 85 or 95 d on test for year 1 and 145 or 152 d on test for year 2. Following harvest, ADG, liveweight, carcass traits, WBS, sensory traits, fatty acid profile, and lipid oxidative stability were analyzed from the longissimus muscle. The type of forage did not affect (P > 0.05) ADG, liveweight, dressing percentage, kidney, heart, and pelvic fat, marbling, yield grades, quality grades, lean maturity scores, bone maturity scores, or pH. Steers finished on ryegrass had heavier (P < 0.05) HCW than rye and oats. Year did not affect (P > 0.05) liveweight, kidney, heart, and pelvic fat, marbling, preliminary yield grade, actual yield grade, quality grades, and bone maturity scores. Year 1 had higher (P < 0.05) ADG, but lower (P < 0.05) HCW, dressing percentages, adjusted yield grades, lean maturity scores, and pH. Lipid oxidative stability was not significant (P > 0.05) among forage type, year, or forage*year groups. Forage*year did not have a significant affect (P > 0.05) on L*, a*, or b* values for fat or lean color. Forage type did not affect (P > 0.05) fat L* or b*, lean L*, a*, or b* values. Ryegrass and oats had higher (P < 0.05) fat a* values than rye. Year did not affect (P > 0.05) fat L* or b*, or lean L* values. Sensory traits, WBS, and cookloss were not affected (P > 0.05) by forage type. Off flavor, WBS, and cookloss were not affected (P > 0.05) by year. Year 1 had higher (P < 0.05) sensory panel rating for juiciness, tenderness, and flavor intensity. Off-flavor descriptors were not affected (P > 0.05) by forage or year. Year did not affect (P > 0.05) C8:0, C9:0, C11:0, C11:1, C12:0, C12:1, C13:0, C13:1, C14:0, C14:1, C16:1t, C20:3n3, C20:5n3, C22:0, C22:1, C22:4, C22:3, and C24:1 concentrations. Year affected (P < 0.05) saturated, mono, poly, omega-6, and omega-3 fatty acid concentrations.
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