Author
Cushman, Robert - Bob | |
TENLEY, SARAH - University Of Nebraska | |
SOARES, EMERSON - Universidade Federal De Santa Maria | |
MCNEEL, ANTHONY - Zoetis |
Submitted to: Meeting Proceedings
Publication Type: Proceedings Publication Acceptance Date: 4/28/2017 Publication Date: 5/15/2017 Citation: Cushman, R.A., Tenley, S.C., Soares, E.M., McNeel, A.K. 2017. Improving calving day to improve lifetime productivity. In: Proceedings of the XLV Uruguayan Buiatric Congress, June 8-9, 2017, Paysandu, Uruguay. p. 61-67. Interpretive Summary: In U.S. production systems, a beef heifer must wean between 3 and 5 calves to pay for her development cost; however, data from the northern plains clearly demonstrates that only 50% of the heifers that conceive in the first breeding season remain in the herd to produce 3 calves. Thus, there is a critical need to improve the reproductive efficiency of replacement heifers to increase their reproductive longevity. Among these heifers, those that give birth in the first 21 days of their first calving season produce more calves and wean more pounds of calves in their lifetime. An interesting set of biological questions becomes: 1) What is different about these heifers that conceive earlier that contributes to their greater reproductive longevity? 2) Can we identify these differences and use them as biomarkers to identify the heifers that will conceive early? and 3) Are these differences static or can we intervene between weaning and breeding to improve the reproductive performance of those that are not destined to produce a large number of calves? This paper will address the first two questions, and the companion paper will address the final question. Technical Abstract: In U.S. production systems, a beef heifer must wean between 3 and 5 calves to pay for her development cost; however, data from the northern plains clearly demonstrates that only 50% of the heifers that conceive in the first breeding season remain in the herd to produce 3 calves. Thus, there is a critical need to improve the reproductive efficiency of replacement heifers to increase their reproductive longevity. Among these heifers, those that give birth in the first 21 days of their first calving season produce more calves and wean more pounds of calves in their lifetime. An interesting set of biological questions becomes: 1) What is different about these heifers that conceive earlier that contributes to their greater reproductive longevity? 2) Can we identify these differences and use them as biomarkers to identify the heifers that will conceive early? and 3) Are these differences static or can we intervene between weaning and breeding to improve the reproductive performance of those that are not destined to produce a large number of calves? This paper will address the first two questions, and the companion paper will address the final question. |