Effects of Bull Exposure on Postpartum Intervals and Reproductive Performance in Beef Cows: A progress Report

The effects of bull exposure on time from calving until estrus, conception rates and calving interval were studied for mature beef cows. In the spring of I985 and 1986, cows were randomly allotted to one of two treatment groups. Cows were exposed to vasectomized bulls after calving until breeding or no bull exposure. Cows were heat detected twice daily and blood samples were collected weekly to determine progesterone levels. Heat detection data and progesterone levels indicated onset of estrous cycles occurred earlier in bull exposed cows than non-exposed cows. Conception rates to a timed insemination were not different between the two groups. Bull exposed cows tended t o calve earlier