Estimation of genetic parameters for growth, feed consumption, and conformation traits for double-muscled Belgian Blue bulls performance-tested in Belgium.
Withers height at 7 and 13 months of age, body weight at 7 and 13 months of age, average feed intake of concentrates, average daily gain, average feed intake of concentrates/daily gain, average feed intake of concentrates/mean metabolic weight and price/kg live weight (based on muscle conformation) were measured in 1442 performance tested Belgian Blue bulls. Restricted Maximum Likelihood with a derivative-free algorithm was used to estimate (co)variance components because there were different models and missing values per trait. Estimates of h2 were all >0.50 except for average feed intake/average daily gain (0.16) and average feed intake/mean metabolic weight (0.33). Estimates of genetic and phenotypic correlations between height at withers and weight traits were positive and moderate to high. Average daily gain showed a negative genetic correlation with body weight at 7 months of age (-0.68), but had positive correlations with height at withers at 13 months and body weight at 13 months (0.22 and 0.43, respectively). Muscle conformation expressed as price/kg live weight was related to low average feed intake/average daily gain. Average feed intake was highly correlated with weight at 7 and 13 months of age. Average feed intake/average daily gain had a high negative genetic correlation with average daily gain (-0.89).