Grading, Two- and Three-Breed Rotational Crossing as Systems for Production of Calves to Weaning

Crossbreeding beef cattle is now an accepted method of commercial cattle production in the United States. Available evidence indicates that there are heterotic effects on traits of importance in the economical production of beef. The introduction of exotic breeds and the reconsideration of the merit of dairy cattle have added interest in systematic schemes of crossbreeding which might maintain near maximum levels of hybrid vigor, while blending the desirable qualities of two or more breeds in offspring. The alternative to crossbreeding for commercial cattle production is grading to breeds of proven merit. This experiment with purebred Angus, Polled Hereford and Santa Gertrudis bulls and grade and crossbred females had the following objectives: (1) to compare grades with crossbreds, (2) to estimate the effect of breeds in grading systems and breed of sire in crossbreeding systems and (3) to compare two-breed and threebreed rotational crossing. The study includes the production of three-breed cross dams but high grade females of all three groups were not available initially.