Genetic and Environmental Factors Affecting Performance Traits of Hereford Bulls

Abstract
Data on 1,029 bulls that were performance tested at the United States Range Livestock Experiment Station, Miles City, Montana, were used in the analysis. The effects of environmental and genetic factors affecting pre-and post-weaning performance are presented and discussed. Age of dam was a significant source of variation for all traits studied except 196-day postweaning gain. Heritability estimates of 0.40 and 0.48 were obtained for feedlot gain and final weight, respectively. Phenotypic, genetic, and environmental correlations among pre- and post-weaning performance traits are presented. The correlations generally were positive, and no serious negative relationships were found that would retard progress from selection for increased weights and gains. Copyright © . .