Effect of Pubertal Status and Number of Estrous Cycles Prior to the Breeding Season on Pregnancy Rate in Beef Heifers

Authors

Rebecca A. Vraspir, University of Nebraska–Lincoln
Adam F. Summers, UNL West Central Research and Extension CenterFollow
Andrew J. Roberts Roberts, USDA-ARSFollow
Rick N. Funston, UNL West Central Research and Extension CenterFollow

Date of this Version

2014

Citation

2014 Nebraska Beef Cattle Report, UNL Extension MP99, pp. 5-7.

Comments

Copyright © 2014 University of Nebraska.

Abstract

Three experiments were conducted to evaluate whether pubertal status and number of estrous cycles prior to breeding influences pregnancy rate in beef heifers. Pubertal heifers were heavier and older at the start of breeding and had greater AI and overall pregnancy rate than non-pubertal heifers. Second season pregnancy rate was greater for heifers reaching puberty prior to first breeding and for heifers having ≥ 2 estrouscycles prior to breeding compared with non-pubertal heifers. Pregnancy rate was greater for heifers achieving puberty prior to breeding; however, earlier onset of puberty did not significantly improve first pregnancy rates.