Heterosis in Preweaning Traits of Beef Cattle

Abstract

THE phenomenon of heterosis has long been observed in domestic animals. It is now utilized extensively in commercial swine and poultry production. This paper reports results from an experiment designed to evaluate heterosis effects on traits of economic value in beef cattle. It includes the results of analyses of heterosis effects on birth weight, average daily gain from birth to weaning, weaning weight and weaning conformation score. This experiment included the production of straightbreds of the Hereford, Angus and Shorthorn breeds and the six reciprocal crosses among them. These breeds were chosen because they are most frequently used for production of beef in the United States. The influence of heterosis was estimated by comparison of the crossbreds with the average of the straightbreds sired by the same bulls and out of comparable cows. Thus, the difference between crossbreds and straightbreds is due to non-additive gene effects. Materials and Methods The experiment was started in 1957 with high grade heifer calves of the Hereford, Angus and Shorthorn breeds.