Estimates of genetic parameters for carcass traits in Finnish Ayrshire and Holstein-Friesian

The aim of this study was to estimate genetic parameters for slaughter weight, and carcass fleshiness and fatness in Finnish Ayrshire and Holstein-Friesian bulls and heifers. Animal model, sire model and sire maternal grandsire model were tested for their suitability to evaluate young sires in progeny test. There were 38 188 records on animals slaughtered in two slaughter houses during a period of 20 months. Effects of year-month of slaughter, age at slaughter, sex and breed were statistically significant, and herd accounted for about 20–57% of the total variation in the data. Estimates of heritability in the different breed by sex data sets were in range of 0.07–0.14 for slaughter weight, 0.16–0.31 for fleshiness and 0.08–0.16 for fatness, whereas the corresponding within herd heritabilities varied from 0.15 to 0.29, 0.29 to 0.39 and 0.12 to 0.29, respectively. There was a positive genetic correlation of 0.38–0.66 between slaughter weight and fleshiness, whereas fatness was not genetically correlated with the other studied traits. All within herd correlations were high, from 0.55 to 0.93, and phenotypic and environmental correlations were also high or moderate. In the estimation of (co)variance components, sire model and sire maternal grandsire model were preferred to animal model due to computational requirements, and sire maternal grandsire model to sire model due to the possibility of including the sire path of maternal pedigree.  2000 Elsevier Science B.V. All rights reserved.