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Exposure Data
To collect reproductive data on potential replacement heifers, a yearling heifer exposure inventory must be produced. This inventory would typically be sent to breed associations in May for spring-born heifers and in November for fall-born heifers. On the inventory, producers should indicate breeding season start and end dates, individual exposure status, management group, and disposal information. Differences among management groups in post-yearling feeding, management, or mating practices should be recorded.
General recommendation for exposing heifers is 2 to 3 weeks before older cows to allow for enough time to return to estrus after their first calving. This will help first-calf heifers return from the postpartum interval and cycle again in the same time-frame as older cows in the herd [1] [2] . It is also recommended that heifers conceive by approximately 14 months of age so that they calve as a two-year-old. Age should be balanced with estrous activity, where exposing heifers on their pubertal estrus should be avoided. Instead, it is recommended that heifers be actively cycling 1 to 3 months prior to exposure to bulls for breeding [3].
References
- ↑ Geary, T.W. 2003. Management of young cows for maximum reproductive performance. Proc. 2003 Beef Improvement Federation Annual Convention. [1]
- ↑ Lents, C.A., R.K. Peel, G.E. Seidel, Jr., and G.D. Niswender. 2003. Reproduction on the ranch. Proc. Range Beef Cow Symposium XVIII, Mitchell NE. [2]
- ↑ Byerley, D.J., R.B. Staigmiller, J.G. Beradinelli, and R.E. Short. 1987. Pregnancy rates of beef heifers bred either on puberal or third estrus. J. Anim. Sci. 65:645-650. [3]
