Genotype by environment interaction for lamb weaning weight in the Norwegian White Sheep breed

Abstract

Genotype by environment (G×E) interaction effects influence phenotypic expressions of a trait and may be of importance for sheep breeding. Interaction effects are more likely to be present when there are large environmental differences. Norwegian sheep usually graze mountain or forest pastures during summer. In this study, we estimate G×E interactions in Norwegian White Sheep as genetic correlation between area-specific traits (autumn lamb weight) in three ram circles located in two different counties; two in Buskerud in the south and one in Troms to the north of the country. Using data from the National Sheep Recording System, a bivariate animal model was fitted and genetic correlations for each trait were obtained. None of the correlations were significantly different from unity indicating the absence of G×E interaction effect for weaning weight. To gain further insight, studies should include a breeding-goal level aggregation of all traits thought to contribute to profitability.