Follicular development of beef heifers exposed to bulls during an estrus synchronization protocol that included a 14-day CIDR, PGF2ɑ, and timed artificial insemination (AI) and GnRH

Authors

J.G. Berardinelli*, L.E. Ramos, J.R.C. Wilkinson, J.R. Olsen, T. Gibbs, L. Runnion, and S. A. Tauck1

Impact statement

Our results indicate that the continuous presence of mature bulls during an estrus synchronization protocol that included a CIDR for 14 days does not appear to influence ovarian follicular dynamics or the expression of estrus after PG injection in beef heifers. Thus, this may not be the mechanism whereby the presence of bulls increases fertility in the bovine. However, the relationship between the dominate follicle (ovulatory follicle) diameter and body condition score supports the concept that “more fit” females ovulate larger follicles which in turn improves fertility and reproductive efficiency in beef heifers.

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