Genetic parameters of direct and ratio traits from field and station tests of pigs
Abstract. Genetic parameters of several growth and carcass traits were estimated for the Hungarian Large White (HLW) and Hungarian Landrace (HL) pig breeds. The objective of the analysis was to compare the direct (days on station test, consumed feed, valuable cuts and age) and ratio/composite (net daily gain, feed conversion, proportion of valuable cuts, lean meat percentage and average daily gain and meat quality score) traits, which were collected in the course of station and field tests. The analysis was based on the national database (1997–2003) using univariate and bivariate animal models. Estimated heritabilities for station test traits ranged between 0.34–0.69 (except for meat quality score, where the heritability was low (0.10, 0.15 for HLW and HL, respectively) and exceeded that of the field test traits (0.18–0.23). Relative importance of random litter effects was low for the station test traits (0.01–0.29) but moderate for the field test traits (0.20–0.48). The unfavourable genetic correlation between lean meat percentage and meat quality score (−0.28, −0.44 for HLW and LW, respectively) is worth mentioning. In both performance tests the direct and ratio test counterparts showed similar heritabilities and their genetic correlation were close to unity (0.74–0.95). Based on these results selection on either the direct or on the ratio traits would possibly result similar selection response.