Stockpiled Tifton 85 Bermudagrass Followed by Grazed Winter Cover Crops as Part of a Stocker Production System for South Alabama
Type of DegreeMaster's Thesis
MetadataShow full item record
A 2-yr grazing study was conducted in the fall of 2014 (Yr 1) and 2015 (Yr 2) to evaluate the use of stockpiled Tifton 85 (T85) for backgrounding stocker cattle compared with feeding hay plus supplement during the fall forage deficit gap. The study consisted of six 0.75-ha paddocks of stockpiled T85 and six 0.20-ha drylot paddocks for feeding T85 hay. Treatments included: Stockpiled T85 or T85 hay only (no supplement), stockpiled T85 or T85 hay plus 0.2 kg cottonseed meal and 0.7 kg soybean hulls/head/day (65 g RUP/kg supplement CP) (25/75), and stockpiled T85 or T85 hay plus 0.45 kg cottonseed meal and 0.45 kg soybean hulls/head/day (142 g RUP/kg supplement CP) (50/50). In Yr 1, steers (initial BW 280 ± 38 kg) were randomly assigned to treatments on November 11 and removed on January 6, and in Yr 2 steers (initial BW 247 ± 21 kg) were randomly assigned to treatments on October 28 and removed on December 21. Polytape fencing was used in for frontal grazing stockpiled T85 paddocks to allocate a 3- to 4-d allotment of forage DM for the animals based on 1) the available forage mass and 2) steer DMI requirements. In both Yr 1 and Yr 2, there were no differences (P > 0.10) among treatments in mean forage mass (5,099 kg DM/ha and 7,998 kg DM/ha in Yr 1 and Yr 2, respectively), forage allowance (1.9 kg DM/kg steer BW and 3.0 kg DM/kg steer BW) and percent forage utilization (84% and 88% in Yr 1 and Yr 2, respectively). No differences (P > 0.10) were detected for nutritive value parameters CP, ADF, NDF, and TDN among treatments in stockpiled T85 or T85 hay in both years. However, there were differences (P < 0.0001) across sampling dates for stockpiled T85 treatments only. Pre-graze forage quality in Yr 1 and Yr 2 generally declined as the grazing season progressed. In Yr 1, steer mean initial BW, mean final BW, and ADG did not differ across all treatments (P = 0.3785). However, differences were detected for these parameters in Yr 2. In Yr 2, mean ADG was greater for stockpiled T85 treatments with supplementation than hay + 50/50, but intermediate to the hay + 25/75 treatment. Mean ADG of the treatments with no supplementation were less than those receiving supplementation. In Yr 1, all but one treatment (Hay + 50/50) experienced a negative mean ADG. Stockpiled T85 supplemented with CP and energy can support stocker cattle at a level of maintenance, but to achieve a desired gain of 0.9 kg/day, there must be a greater level of supplementation implemented into the program. A 2-yr grazing study was conducted in the winter through spring 2015 (Yr 1) and 2016 (Yr 2) to evaluate combinations of cool-season annuals for supporting a winter/ spring grazing system for stocker producers as cover crops to use prior to fields being utilized for row crops. Twelve 1.21-ha paddocks with 4 replications and 3 treatments in Yr 1 and 3 replications of 3 treatments in Yr 2 were grazed. Treatments included combinations of: Florida 401 rye and Earlyploid annual ryegrass (R-E), Florida 401 rye and Marshall annual ryegrass (R-M), and Florida 401 rye and RAM Oats (R-O). Treatments were arranged in a completely randomized design. Steers (initial BW 279 ± 49 kg) were randomly assigned to treatments on February 5 and removed on April 3 in Yr 1. In Yr 2, steers (initial BW 281 ± 17 kg) were randomly assigned to treatments on in early Ferbuary, and removed during mid-March according to forage availability.. Mean forage mass and forage allowance across both Yr 1 and Yr 2 did not differ among treatments (P > 0.10). For Yr 1, there were no significant differences in CP, ADF, NDF, and TDN (P > 0.10); however, in Yr 2, there were significant differences among treatments in CP (P = 0.0114), ADF (P < 0.0001), NDF (P < 0.0001), and TDN (P < 0.0001). In Yr 2, R-O and R-E had greater nutritive quality than R-M. As expected, in both years the forage quality of all treatments generally declined as the grazing season progressed. Mean initial BW and final BW in both years did not differ across treatments (P > 0.10). Additionally, there were no significant differences in mean ADG across treatments in Yr 1 and Yr 2 (P = 0.2130 and P = 0.4534, respectively). Cool-season annual forages such as small grains and ryegrass may be planted in mixtures and utilized for winter grazing systems in cover crop systems. Using mixtures of ryegrass and small grains that differ in their individual growth pattern proved to have a more even distribution and maintained high nutritive value throughout the grazing season.