Genotype-Environment Interaction in Milk Production under Sri Lanka and Danish Conditions

Abstract
First lactation records from 230 daughters of 37 Danish Jersey bulls exported as heifers to a Sri Lanka state farm were analyzed and compared with results from corresponding half-sib groups under Danish field conditions. The ratio of the Danish mild yield level to the Sri Lanka level was 2.6. Heritability estimates of 0.11 and 0.08 were obtained for milk and butterfat yields in Denmark as compared with an estimate of 0.22 for milk yield in Sri Lanka. The genetic correlation between milk yields in the 2 environments is 0.08, which indicates a real genotype .times. environment interaction.