Genetic polymorphism of Pit-1 gene associated with milk production traits in Holstein cattle

Abstract

The aim of this study was to evaluate the effect of Pit-1 gene polymorphism on long-life milk production traits in the selected population of Holstein cattle. Biological material was obtained from hair roots of 89 Holstein cows originating from the farm with high milk production in Slovak Republic. We use the PCR – RFLP method to detect Pit-1 gene polymorphism (restriction enzyme HinfI). In cows population we identified the presence of all three genotypes: AA genotype (260 bp) of 5 cows, genotype AB (260 bp, 190 bp, 70 bp) of 23 cows and BB genotype (190 bp, 70 bp) of 61 cows. The highest frequency had homozygous BB genotype (69%). The frequency of occurance of allele B (0.81 ± 0.03) was higher than the frequency of allele A (0.19 ± 0.03). The level of locus polymorphism in the analyzed population was median (PIC=0.2564). We observed unbalanced activity of alleles (Ne=1.43) and a higher ratio of homozygous individuals, which caused decrease of expected heterozygosity (He=0.31). Evaluation of Pit-1/HinfI genotype effect on milk production traits was carried out with linear models (GLM procedure). Based on the selected effect we were able to estimate the variability of analyzed traits on 79%. The Pit-1/HinfI genotype affected the variability of milk, protein and fat yield in long-life production only non-significant (P>0.05).