Gnetic trend comparison for production traits in dairy cows resulted from Iranian and imported sperms (case study: Markazi province)

Native and foreign sperms have been used to improve milk traits. Therefore it is necessary to investigate their effects on economic traits. In this study, 16,384 production records were used to compare Iranian and imported sperms effects on milk traits. The data were collected from 74 Holstein cattle herds of Markazi province by the Animal Breeding Center of Iran durin 2001-2013. Data editing was performed using Microsoft Excel software. A general linear model (GLM) procedure of SAS 9.1 software was used to analyze the fixed effects (herd, month of calving, year of calving and sperm type) and effect of calving age as covariate on production traits. Data were analyzed using one-trait animal model by Wombat software and genetic trend (kg/year) was calculated based on calving year. Results of milk traits showed that there was a significant difference between progeny of American and Iranian sperms as compared to offspring of other sperms (Canadian, Dutch, French, Italian and New Zealand). Genetic trends (kg/year) of milk traits were non-significant between daughters of American and Iranian sperms. However, differences of genetic trends (kg/year) were significant between daughters of American and Iranian sperms as compared to daughters of Canadian, Dutch and French sperms (P