Download or read book Genotype by Environment Interaction in Milk Production and Reproductive Traits Among Holstein Cows Producing in Mexico and United States Environments written by Eugenia Cienfuegos and published by . This book was released on 1998 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: To quantify genotype by environment interaction for mature equivalent milk production in northeastern US and Mexico, mature equivalent records of 55,162 Holstein cows from 1,339 sires of first three lactations in Mexico and first lactation records of 499,401 Holstein cows from 663 sires in the U.S. were analyzed. There were 474 sires in common. Herd-year standard deviation classifications were used to define high ($\geq$1,600 kg) and low ($\leq$1,300 kg) Mexican data files and a low ($\leq$1025 kg) U.S. data file. These data files were used to determine whether information from US herds with low environmental opportunity better predicts yield response in the alternative Mexican environments. Genetic and phenotypic parameters were estimated with multiple trait derivative-free REML methods. Genetic correlation coefficients between pairs of traits in different environments were tested for difference from unity using the likelihood ratio test. Heritability estimates across Mexican environments were about 0.18, and across US environments about 0.21. Using all the US data genetic correlation coefficients were less than unity (P $