Reproductive performance of Jersey heifers submitted for first insemination based on age vs. body weight – a randomized controlled trial

Abstract

Raising replacement heifers represents a major cost on a dairy farm. The ideal time to submit a heifer to insemination is a balance between reproductive biology, growth, and econom­ics. While getting heifers pregnant sooner may reduce raising costs, it may compromise their future productive performance. The objective of this study is to compare the reproductive per­formance of Jersey heifers submitted for first insemination (AI) based on age vs. body weight (BW). We hypothesize that the re­productive performance of heifers moved to the breeding pen (BP) based on a minimum BW would not be inferior to that of heifers moved based on minimum age.