Genetic parameters for and Blad effects on beef production traits and disease frequency

Abstract

Beef production traits measured on 6292 performance tested Danish Friesian bulls from 1973 to 1992 were analysed together with disease records for 4621 bulls performance tested from 1981 to 1992 using a threshold model. Univariate Gaussian and polychotomous and bivariate Gaussian‐binary mixed models with Bovine Leukocyte Adhesion Deficiency (BLAD) test information were used. Danish Friesians were found to have a larger ultrasonic muscle area than North American Holstein‐Friesians and favourable heterosis was observed for daily gain and feed utilization. Carriers of BLAD were observed to have poorer feed utilization than non‐carriers and tended to grow slower and to have a lower incidence of disease treatments. Estimated heritabilities for beef production traits ranged from 0.29 to 0.39. For disease frequency analysed as polychotomous and as binary, the estimated heritabilities ranged from 0.08 to 0.19 and from 0.12 to 0.33, respectively. Simulation showed that heritability estimates tended to be biased with increasing number of pooled categories. Phenotypic and genetic correlations between disease frequency and beef production traits ranged from — 0.32 to 0.10 and from — 0.43 to 0.23, respectively.