Dairy productivity of Holstein cattle with different genotypes of the β-lactoglobulin gene (BLG)

Abstract

The article covers the study of the effect of β-lactoglobulin gene polymorphism on daity productivity, qualitative composition of milk and lactation activity of Holstein cows. The work was carried out on 146 animals in the Lenin Breeding Farm Integrated Agricultural Production Center (IAPC) of the Republic of Tatarstan. DNA genotyping by the locus of the Bos taurus BLG-Hae III gene was performed by PCR-RFLP. As a result of genetic typing of cattle, 2 alleles (A – 0.651 and B – 0.349) and 3 genotypes (AA – 41.1, AB – 47.9 and BB – 11.0 %) were identified. The chi-square criterion is below the critical value (5.99; p < 0.05) and testifies that the Hardy-Weinberg genetic equilibrium is not disturbed in the population. The evaluation of dairy productivity traits showed that cows with the AB genotype have the highest milk yield and high-quality milk. The heifers with the AB genotype are characterized by the best lactation curve throughout lactation. The difference in the amount of milk received between cows with the AB genotype and animals with the AA and BB genotypes is 71.6 kg (or 9.3 %) and 95.7 kg (or 16.9 %), respectively. Cows with low milk yields (genotype AA) had the lowest lactation decline (4.34) and greater stability (99.9).