Estimation of milk production genetic and phenotypic trends in Holstein cattle in Mexico

Records of milk production adjusted to 305 d, adult equivalent of the first lactation and two milking were used. Those come from the National Breeding in Mexico PNMG (n = 163.885), which includes records of the Holstein Association of Mexico (AHM) (n = 43.668) and National Bank of Dairy Information (BNIL) (n = 120.217). Best Linear Unbiased Predictor method was used to predict breeding values (VG) of animals. ASREML software was used with an animal model that included herd-year group-season as fixed effect and animal and residue as random effects. Averages of VG per sire were estimated weighted by the number of daughters and unweighted for PNMG, AHM and BNIL. Also, we estimated the weighted average of the sires VG of the PNMG according to their country of origin (USA, Canada, Other, Mexico). We also estimated the average of VG and phenotypic values (VF) for dairy cows. The average of VF and VG for cows PNMG, AHM and BNIL increased between 2007 and 2011. Breeders of the AHM chose sires with greater VG than the BNIL. However, breeders of BNIL used sires with high VG used more frequently. The VG for foreign sires were higher than national sires and were more commonly used by farmers.