Investigation of the Relationship between GH and PIT-I Gene Polymorphisms and Milk Yields in Simmental Cattle Breed

The aim of this study was to investigate the relationship between growth hormone (GH) and pituitary-specific transcription factor-1 (PIT-1) genes and 1th, 2nd lactation total milk yield and daily milk yield in Simental cattle breed. In this study 203 Simmental dairy cows, reared in Kayseri vicinity, were examined. In order to determine GH genotypes, 223 bp PCR products obtained by PCR were digested with AluI restriction enzyme. In order to determine PIT-1 genotypes, 600 bp PCR products obtained by PCR were digested with HinfI restriction enzyme. The mean differences of 305-day milk yield among the genotype groups of GH-AluI and PIT-1-HinfI were assessed by one-way analysis of variance (ANOVA). Two alleles (A and B) and three genotypes (AA, AB and BB) for GH-AluI polymorphism were observed in examined Simmental cows. The LL genotype frequency was found highest (0.52) and the VV genotype frequency was found the lowest (0.11) in examined Simmental cows. The frequency of the L allele was found higher (0.7) than V allele (0.3) in this study. Two alleles (A and B) and two genotypes (AB and BB) for PIT-1-HinfI polymorphism were observed in examined Simmental cows in this study. The AA genotype was not found in the examined samples. The BB genotype frequency was found to be highest (0.74) in examined Simnetal cows. End of the study, the genotype effects for GH-AluI and PIT-1-HinfI polymorphisms on daily and lactation total milk yield were not found to be significant in examined Simmental cows (P>0.05). It was thought that further studies on the association between GH-AluI and PIT-1-HinfI polymorphism and other milk yield traits and meat yield traits in Simmental cattle breed should be conducted.