|Mayeux Jr, Herman|
Submitted to: Professional Animal Scientist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 27, 2006
Publication Date: September 28, 2006
Citation: Phillips, W.A., Grings, E.E., Short, R.E., Heitschmidt, R.K., Coleman, S.W., Mayeux Jr, H.S. 2006. Impact of calving season on stocker and feedlot performance. Professional Animal Scientist 22:392-400. Interpretive Summary: The profitability of vertically integrated beef enterprises are dependent upon shifting a greater proportion of the weight gain to the segment that is the most efficient or has the least-cost/lb of body weight gain. Delaying the calving season will decrease winter feed cost, but will shift more of the calf body weight gain to the stocker and finishing phases of the enterprise. Calves born in the northern Great Plains, but destined to be finished in the southern Great Plains (SGP), should be transported to the SGP as soon as possible after weaning to lessen transportation cost. Although finishing these calves on pasture produced leaner carcasses, pasture finished calves were not as efficient in converting feed to gain as calves finished in dry lot.
Technical Abstract: Delaying calving from late winter to late spring can decrease winter feed cost for rangeland-based cow-calf enterprises in the northern Great Plains, but calves born later in the year will have less BW upon entry into the feedlot. The objective of this experiment was to determine the impact of calving system and previous stocker management on feedlot performance. Cows were assigned to late winter (LW), early spring (ES) or late spring (LS) calving seasons. Steers in the LW and ES groups were weaned at 190 and 240 d of age. Steers in the LS group were weaned at 140 and 190 d of age. One group of steers was shipped to Oklahoma after weaning. Another group was retained in Montana for backgrounding after weaning and then shipped Oklahoma in the spring for finishing in dry lot or on pasture. Steers born in LW had greater (P < 0.05) BW at the beginning and end of the finishing phase than calves born in ES or LS, but lesser (P < 0.10) finishing phase ADG. Calves born in LS had leaner (P < 0.05) carcasses with lower (P < 0.05) marbling scores than calves born in LW or ES. Steers calves backgrounded in Montana and then shipped to Oklahoma for finishing had less (P < 0.05) BW at the end of the finishing period and less ADG during the finish period than steers backgrounded in Oklahoma, but greater (P < 0.05) marbling scores. Steers finished on pasture had less (P < 0.01) ADG and produced leaner carcasses, but were not as efficient in converting feed DM to gain as steers finished in dry lot. Delaying the calving season to decrease winter feed cost produces steers with lighter weaning BW. As a result, more BW gain must be achieved during the stocker and finishing phases. Finishing cattle on pasture was not as efficient as finishing cattle in dry lot.