Associations between the AluI polymorphism of growth hormone gene and production and reproduction traits in a Hungarian Holstein-Friesian bull dam population

The aim of this paper was to study the polymorphisms of bovine growth hormone gene. The authors genotyped 363 Hungarian Holstein-Friesian bull dams from 6 farms all over the country. Two variants (L and V) of the bovine growth hormone gene digested with AluI enzyme were identified in the experiment. Genotyping was carried out by PCR-RFLP method. The frequency data of L and V allele was 0.93 and 0.07 respectively. Distribution of the three genotypes were 87.05% (LL), 12.40% (LV) and 0.55% (VV). The studied population was in H-W equilibrium considering the genotype distribution. SPSS 11.0 for Windows was used to reveal the possible correlations between GH genotypes and production and reproduction traits and further statistical analyses. On the basis of statistical analyses it can be found that VV genotype cows had the longest milking period and LL had the shortest dry period. Both differences were significant. Cows with LV genotype had significantly higher test milking data than LL cows. Furthermore, LV genotype seemed to be advantageous for 305 days lactation milk yield. While milk composition traits, as 305 days milk fat and protein percent showed the opposite tendency, since LL genotyped dams produced significantly higher values in these traits.