Alteration of the Bovine Estrous Cycle with Oxytocin

Abstract

The daily administration of natural or synthetic oxytocin to post-puberal nonlactating dairy heifers, during the first week of the estrous cycle, resulted in marked shortening of the diestrual period, the next heat occurring from eight to 12 days after the previous estrus, instead of the usual 21 days. These precocious heat periods appeared normai in every respect, being followed in all eases by ovulation at the expected time. In all eases, the subsequent diestrual periods were of normal lengths.