Associations of Growth Hormone Gene Polymorphisms with Milk Production Traits in South Anatolian and East Anatolian Red Cattle

The current study was undertaken to determine the relationship between milk production traits of Eastern Anatolian Red (EAR) and South Anatolian Red (SAR) breed cows and polymorphisms of Growth Hormone gene (GH) which is a potentially effective Quantitative Trait Loci (QTL) on milk production traits. Fifty cows that were newly delivered calves from each of EAR and SAR breeds were used. Triplicate milk samples were obtained between 0-30, 50-180 and 270-300 days of lactation period. Milk samples were analyzed for milk fat, protein, dry substance, refraction indices and somatic cell count. In addition, DNA samples were obtained from blood samples of each cow and AluI and MspI polymorphisms in GH were determined using PCR-RFLP method. In both breeds, AluI polymorphism with VV genotype cows had higher milk fat percentage compared to other genotypes. Similarly, in SAR cows, those with MspI polymorphism and -/- genotype had higher milk fat percentage compared to other genotypes. The relationship between GH gene polymorphisms and other milk quality parameters could not be established. As a result, it can be concluded that GH gene polymorphisms can be of a valuable parameter to be used for selection of EAR and SAR cows for improving milk fat percentage