Genetic differences among the predominant beef cattle breeds in Canada: An analysis of published results

Published information on the relative performance of beef breed crosses was used to derive single estimates of purebred breed values for the predominant beef breeds in Canada. A range of commercial traits was considered. The breed cross estimates were taken from four large breed comparison trials from 1970 to 1983, each with representative samples of the breeds from the North American population. Variances of the breed cross estimates, derived allowing for the number of sires and progeny sampled, were used in a Weighted Least Squares analysis to obtain single purebred breed effects. Birth weight, and growth rate breed values were also expressed on a 1991 base by adjusting for the estimated breed genetic trends. Important genetic differences are shown to exist between the breeds for many of the traits. Breeds with larger mature size tended to be larger and leaner at a constant age and better for maternal calving ease and maternal calf survival. In contrast, smaller breeds were superior in their direct genetic contribution for calving ease and calf survival. Angus were more fertile and Simmental less fertile than the other breeds. Knowledge of these differences has a wide range of applications, including the provision of a biological basis for the economic comparison of breed crossing systems and for the definition of breed roles in beef production.