Joint Nordic Genetic Evaluation of Growth and Carcass Traits in Dairy Breeds

A growth index was developed and will be included in the Nordic Total Merit Index (NTM). It combines EBVs for daily carcass gain (CG) and carcass conformation score (CS). The evaluation is a multiple trait animal model using information from fattening bulls. The carcass gain is divided in carcass gain for a short intensive fattening period (CGS, up to 550 days at slaughter) and a long extensive (CGL, more than 550 days). Fat score (FS) is used as an indicator trait. Heritabilities, estimated in the data, were 0.36,, 0.29, 0.29 and 0.23 for RDC and 0.28, 0.32, 0.29 and 0.18 for Holstein for CGS, CGL, CS and FS respectively. Genetic correlations between CGS and CGL were close to unity, 0.97 for RDC and 0.98 for Holstein.