Relationships between GH/AluI Polymorphism and Some Performance Traits in Holstein Cows

Abstract

The aim of this study is to determine the genotype and allelic frequencies of Growth Hormone (GH) gene, to present the genetic variation, and to research the relationships between the GH genotypes and some milk production traits of 115 organically grown Holstein cows. It was seen that GH gene LL, LV ve VV genotype frequencies is 0.41, 0.49, ve 0.10 respectively, and is stable according to Hardy-Weinberg equilibrium genetic balance test in the cattle population. Moreover, Lactation milk yield averages were found to be 7136 kg, 7470 kg and 8017 kg for the LL, LV and VV genotypes, respectively. There was no statistically significant relationship between the actual lactation milk yield, 305d milk yield, peak daily yield, lactation length averages of different genotypes. In the study, GH/AluI polymorphism was found to be insufficient for improvement of the milk yield traits alone.