Genetic trends for production traits of Holstein cows resulted by imported semen in Fars province

In this study, records of 305-d and first lactation production traits of 13601 Holstein cows were used to estimate genetic parameters and genetic trends for production traits of Holstein cows resulted by imported semen. These data were collected from 218 herds during 1999 to 2013 by Animal Breeding Center of Iran. Procedure GLM software SAS, 9.1 was used for effect fixed (herd effect, semen type, year, month of calving) and age of calving as the covariate. Estimated were genetic and phenotypic variance (co) milk yield, fat and protein percentage traits by Wombat and univariate and bivariate animal model. Heritability of milk yield, fat and protein percentage were (0.23±0.007, 0.46±0.01 and 0.52±0.021) respectively. Genetic correlations between milk yield-fat percentage, milk-protein percentage and protein-fat percentage were (-0.30±0.021, -0.42±0.017 and 0.16±0.001) respectively. Compared the genetic trend milk, fat and protein percentage traits difference between daughters of semen American, Iranian and Canadian was significant (p