Genotype by environment interaction in brazilian and colombian holstein population

The objective of this research was to determine the existence of genotype by environment interaction (GxE) in milk yield (MY) in Holstein cattle form Brazil and Colombia. Data consisted of 47484 and 23591 first lactation of cows daughter of 1898 sires, those at 481 north American sires. REML bivariate animal model analyses were used to estimate genetic correlations for MY between countries. The means of milk yield from Brazil and Colombia where 6589.72 ± 1678.07 kg and 5881.00 ± 1595.91 kg, respectability. The genetic variance in Brazil and Colombia where 470238.78 kg2 and 259546.85 kg2, the residual variances where 951346.52 kg2 e 684076.24 kg2 and the heritabilities 0.31 and 0.28, respectability. The genetic correlation the MY PL between Brazil and Colombia was 0.74 indicated existence of GxE. Therefore, these results incourage to propose that a genetic evaluation program in cattle, may be done in each country, considering its own economical aspects