Title: Feedlot Performance and Carcass Characteristics of Calves From Dams With Different Levels of Winter Supplementation Developed With or Without Feed Restriction During the Postweaning Period Authors
Submitted to: Western Section of Animal Science Proceedings
Publication Type: Proceedings
Publication Acceptance Date: April 15, 2011
Publication Date: June 20, 2011
Citation: Endecott, R.L., Shipp, B.L., MacNeil, M.D., Alexander, L.J., Roberts, A.J. 2011. Feedlot Performance and Carcass Characteristics of Calves From Dams With Different Levels of Winter Supplementation Developed With or Without Feed Restriction During the Postweaning Period. Western Section of Animal Science Proceedings 62:189-192. Interpretive Summary: Harvested feedstuffs are a major input cost for range-based cow-calf producers. A long term study at Fort Keogh has evaluated the influence of 2 levels of nutritional input during heifer development (ad libitum or 20% less feed) and winter supplementation (adequate or marginal) on lifetime productivity in beef females. Bull calves in this experiment also received 2 levels of nutritional input during the postweaning period, but little work has been done to assess feedlot performance and carcass characteristics of these calves. Therefore, the objective of this research was to evaluate the impacts of 2 levels of supplemental feed provided to cows during late gestation and 2 levels of feed provided to their sons during postweaning development on subsequent feedlot performance and carcass characteristics. Calves restricted during the postweaning period gained more weight while eating the same amount of feed during the finishing period compared to calves fed ad libitum during the postweaning period, and steers had similar carcass characteristics regardless of postweaning treatment. Restricted appeared to compensate for the nutritional restriction when it was removed. This could reduce the amount of harvested feedstuffs used in cow-calf production with no negative impact on beef production and quality.
Technical Abstract: Harvested feedstuffs are a major input cost for beef cattle production. The objective of this research was to evaluate the impacts of 2 levels of supplemental feed provided to cows during late gestation and 2 levels of feed provided to their sons during postweaning development on subsequent feedlot performance and carcass characteristics. Bull calves (n = 56) were born from dams receiving adequate (1.8 kg/d; ADEQ) or marginal (1.2 kg/d; MARG) winter supplementation. After weaning, bulls were developed on ad-libitum (Control) or 27% less feed (Restricted) for ~140 d. Bulls were then band-castrated and placed on an 80% corn finishing diet ad libitum. Individual intakes were measured with a GrowSafe system for the final ~100 days of the finishing period. Cattle were harvested at commercial packing plant and carcass data were collected. The analysis of variance model included dam winter supplementation, bull postweaning treatment, and their interaction. Restricted calves gained less (P < 0.01) during the postweaning phase than Control calves (0.63 vs 1.16 ± 0.03 kg/d, respectively). Postweaning treatment did not impact feed intake during the finishing phase (P = 0.30; 13.0 vs 12.6 ± 0.34 kg/d for Restricted and Control, respectively; as-fed basis). However, ADG during the finishing phase exhibited a postweaning × dam treatment interaction (P = 0.03), where Restricted steers from MARG dams gained the most (1.55 ± 0.05 kg/d) and Control steers from MARG dams gained the least (1.26 ± 0.05 kg/d). Steers from ADEQ dams were intermediate (1.45 and 1.36 ± 0.05 kg/d for Restricted and Control). Restricted and Control steers had similar (P = 0.63) final BW (601 vs 622 ± 7 kg), HCW (357 vs 374 ± 5 kg), back fat thickness (1.12 vs 1.19 ± 0.05 cm), ribeye area (86.5 vs 88.4 ± 1.35 cm2), intramuscular fat percentage (5.86 vs 5.69 ± 0.21%),and yield grade (2.69 vs 2.81 ± 0.08). Calves restricted during postweaning development gained more efficiently, and had similar carcass characteristics to their ad libitum-fed counterparts.