The Effect of Artificial Insemination or Natural Service Breeding Systems on Reproductive Performance, Calving Characteristics, Weaning Characteristics, and Steer Backgrounding Performance in a Commercial Beef Herd

Abstract

Two experiments were conducted to evaluate the effects of beef cattle breeding systems that incorporate artificial insemination (AI) or breeding systems that use natural service mating on resultant reproductive performance, calving characteristics, weaning characteristics, and steer backgrounding performance. In Exp. 1, cows and heifers were assigned to 1 of 2 breeding season systems: 1) exposed only to natural service bulls (NS, n = 541) or 2) bred via AI on the first day of the breeding season, followed by exposure to natural service bulls (TAI, n = 535). Final pregnancy rates were similar among treatments. However, more calves were born within the first 21 d of the calving season resulting in heavier weaning weights of calves born in the first 21 d of the calving season for TAI compared with NS. In Exp. 2, steer progeny from females in Exp. 1 were evaluated in a 69 d backgrounding study. Though distinct performance advantages of TAI steers were not observed, calves born early in the calving season had greater feed intake and gain compared with calves born later in the calving season regardless of treatment.