Comparison of TAI at GnRH Injection and Delayed Insemination of Non- estrus Beef Heifers

Authors

Hazy R. Nielson, University of Nebraska-Lincoln
Dan J. Kelly, University of Nebraska-Lincoln
T. L. Meyer, University of Nebraska-LincolnFollow
Rick N. Funston, University of Nebraska-LincolnFollow

Date of this Version

2016

Citation

2016 Nebraska Beef Cattle Reports

Comments

© The Board Regents of the University of Nebraska. All rights reserved.

Abstract

Heifers were estrus synchronized utilizing the melengestrol acetate (MGA)- prostaglandin (PG) protocol. Heifers expressing estrus aft er synchronization were removed from the herd and AI. Heifers not expressing estrus were administered GnRH and either AI at GnRH injection or AI 19 hours following GnRH injection. Heifers AI from estrus detection had a higher pregnancy rate compared with heifers not expressing estrus. Pregnancy rates to AI did not diff er between heifers AI immediately aft er GnRH compared to heifers AI 19 hours aft er the GnRH injection. Th ere was no benefit to delayed AI of non-estrus beef heifers compared with traditional timed AI at GnRH injection.