Breeding Better Beef. 2. Effect of Angus, Hereford, and Santa Gertrudis Sires on Preweaning Performance of Calves

Abstract

The purpose of this study was to evaluate the influence of breed of sire, breed of dam, year of birth, sex of calf, age of dam, heterosis, and crossbreeding effects on preweaning performance of calves sired by Angus, Hereford, and Santa Gertrudis bulls and out of Angus and Hereford cows. The results substantiate previous findings that significant levels of heterosis in preweaning traits may be realized from crosses between the Angus and Hereford breeds, notably where the Angus is used as the dam breed. The increased growth and weaning weight response of Santa Gertrudis-sired calves over that of Angus and Hereford-sired calves indicates that the Santa Gertrudis, as a breed of sire, offers a practical means by which these traits can be improved in herds of predominantly Angus and Hereford breeding. The heritability values obtained for growth rate, weaning weight, and conformation score are of sufficient magnitude to indicate that selection can also be used as an effective method for the improvement of these traits.