Genotype × environment interactions in pig breeding programmes. VI. Genetic relations between performances in central test, on-farm test and commercial fattening

Abstract

Data of the Dutch herdbook breeding programme and data obtained in an experimental progeny test of AI boars under commercial fattening conditions were used to estimate the genetic correlations between traits measured in central test and on-farm test ( r G1), central test and commercial fattening ( r G2) and on-farm test and commercial fattening ( r G3). The genetic correlations were derived from the correlations between best linear unbiased predictions of breeding values in the different environments. A moderate genetic relationship was found between central and on-farm tests; for backfat thickness r G1 = 0.3−0.7, for daily gain r G1 = 0.3−0.65. Differences in definition of the traits and differences in sex of the progeny groups were only partly responsible for the moderate relationships. For identical traits measured in central and on-farm tests on progeny of the same sex r G1 = 0.41 for daily gain and r G1 = 0.70 for backfat thickness. No clear genetic relationship was found between daily gain in central test and commercial fattening ( r G2 = −0.48 to 0.17). However, this correlation was moderately high for carcass characteristics ( r G2 = 0.57−0.64). The genetic correlations between on-farm test and commercial fattening were high for daily gain, r G3 ≊ 1.0 , but low for carcass characteristics, r G3 ≊ 0 . It was concluded that the sire × herd interaction in on-farm test and commercial fattening results is the main factor responsible for the moderate genetic correlations between the different levels of the breeding programme.