Genetic evaluation of carcass traits in dairy cattle

Summary

Two new genetic evaluations on carcass data, extracted from the Normabev database, have been developed by the UMT 3G (Gestion Génétique et Génomique des populations bovines). The first (VB) is a multibreed evaluation of sires on their ability to produce veal calves. It evaluates sires of dual-purpose breeds Montbeliarde (MON) or Normande (NOR) and sires of beef breeds mated with dairy cows. The second (JB) evaluates sires of the MON, NOR and Simmental (SIM) breeds on their ability to produce young bulls for slaughter. The JB evaluation considers three traits simultaneously (carcass weight, age at slaughter and carcass conformation), the VB four (the same three, plus meat color). Heritability estimates are moderate to quite high for carcass weight and conformation (0.12 to 0.37, depending on the breed and the evaluation), lower for age at slaughter and meat color (0.05 to 0.27). Genetic correlations between carcass weight and conformation and between carcass weight and age at slaughter are favorable. Genetic correlations between JB traits on one hand and VB, milk production and female type traits on the other hand were also estimated. These correlations are low to moderate (favorable) between JB and milk production. Hence, meat production traits can be improved without compromising genetic trends on milk production traits too much. JB traits are favorably correlated with VB (0.32 to 0.70) and female type traits.
VB polygenic evaluations became official in 2015. JB polygenic evaluations will be official in 2017. JB and VB genomic evaluations are currently developed in MON and NOR, following the methodology applied in other dairy cattle genomic evaluations.