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

The aim of this study was to estimate genetic parameters for slaughter weig ht, and carcass fleshiness and fatness in Finnish Ayrshire and Holstein-Fri esian bulls and heifers. Animal model, sire model and sire maternal grandsi re model were tested for their suitability to evaluate young sires in proge ny 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, ag e at slaughter, sex and breed were statistically significant, and herd acco unted for about 20-57% of the total variation in the data. Estimates of her itability in the different breed by sex data sets were in range of 0.07-0.1 4 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 gene tic correlation of 0.38-0.66 between slaughter weight and fleshiness, where as fatness was not genetically con elated with the Ether studied traits. Al l within herd correlations were high, from 0.55 to 0.93, and phenotypic and environmental correlations were also high or moderate. In the estimation o f (co)variance components, sire model and sire maternal grandsire model wer e preferred to animal model due to computational requirements, and sire mat ernal grandsire model to sire model due to the possibility of including the sire path of maternal pedigree. (C) 2000 Elsevier Science B.V. All rights reserved.