Title: Effect of heifer calving date on longevity and lifetime productivity Authors
Submitted to: Workshop Proceedings
Publication Type: Proceedings
Publication Acceptance Date: November 15, 2012
Publication Date: December 3, 2012
Citation: Mousel, E.M., Cushman, R.A., Perry, G.A., Kill, L.K. 2012. Effect of heifer calving date on longevity and lifetime productivity. Proceedings, Applied Reproductive Strategies in Beef Cattle, Sioux Falls, SD, December 3-4, 2012. pp. 23-31. Technical Abstract: Longevity and lifetime productivity are important factors in profitability of the beef cow herd. Therefore, a concern for many producers is the productivity and longevity of the individual cow in their herd. The 2007-08 survey from National Animal Health Monitoring System (NAHMS) reported that the largest percentages of cows (33%) are culled because they do not become pregnant during the breeding season. It also reported that 15.6% of all culled cows leave the herd before 5 years of age, and an additional 31.8% leave the herd between 5 and 9 years of age. Research has reported that it takes 5 calves to pay for the development costs and annual maintenance of a replacement heifer (E.M. Mousel, unpublished data). Therefore, to be sustainable, producers need to manage their herd to reduce the number of cows that are culled at a young age. One such management practice is to ensure heifers conceive in their first breeding season. According to research by Patterson et al. (1992) heifers that calve prior to 24 months of age have increased lifetime productivity compared to heifers that calve after 24 months of age. Additionally, if heifers breed early in their first breeding season they will calve early in the calving season and have a longer post-partum interval, which should increase their chance of rebreeding and continually calving early. This management practice is not only beneficial to the dams, but also the calves. Heifers born in the first part of the calving season have been reported to have heavier weaning weights; more had reached puberty prior to the breeding season; and had greater pregnancy success. Steers born early in the calving season had heavier hot carcass weights and greater carcass values (Larson and Funston, 2009; Funston et al., 2011). Therefore, the objective of this study was to determine the effect of a heifer calving date on longevity and lifetime productivity.