Genetic correlations between test station and on-farm performance for backfat thickness and daily gain

Abstract

Performance test of boars (S-) and on-farm test of gilts (F-) for ultrasonic backfat thickness (BF) and daily live weight gain (LDG) were analyzed to estimate the magnitude of genotvpe-environment interaction (GxEI). GxEI was estimated as genetic correlation in multivariate animal model approach. The dataset consisted of 4583 records of boars and 12145 of gilts for three breeds: Swedish Landrace (SL). Large White (LW) and German Landrace (GL) in years 1990 - 1997 for the nucleus herd on farm Ptuj in Slovenia. Altogether, pedigree file contained 19076 animals. Separate analyses were performed for each breed using REML method in VCE 4. Estimated genetic correlations between corresponding traits in station and on-farm tests were high (above 0.9), except for LW (0.50 and 0.44 for BF and LDG, respectively). The heritability estimates were 0.11 - 0.35 for F-BF, 0.23 - 0.40for S-BF, 0.14 - 0.23 for F- LDG and 0.13 - 0.31 for S-LDG. Common litter environment variance accounts for 6 - 23% of the phenotypic variance for BF and 7 - 25% for LDG.