The LGB gene and its effect on milk productivity in dairy cows in Sverdlovsk region

Ural State Agricultural University, Yekaterinburg, Russian Federation

^* Corresponding author: lixodeevskaya@mail.ru

Abstract

The beta-lactoglobulin ( LGB) gene is of considerable interest for studying the protein content and technological properties of milk. The gene is mapped on chromosome 11 and has a size of about 4 kb. LGB is the main whey protein of ruminants and is present in the milk of many animal species. The gene is represented by 11 genetic variants in the genus Bos, among which the A and B alleles are the most common and studied. Genotype data from 300 cattle samples from the Sverdlovsk region were used for the analysis. Beta-lactoglobulin alleles were determined by single-nucleotide polymorphisms using GGP Bovine 150K and Bovine 50K DNA arrays. Phenotypic data were provided by agricultural organizations. The analysis included an assessment of milk yield for 305 days of the first lactation, the percentage of fat and protein, and the total yield of fat and protein. The analysis showed that the B allele prevails in the population (frequency 0.625), while the A allele occurs with a frequency of 0.375. There were no significant deviations from the Hardy-Weinberg law (p-value= 0.55). The average milk yield was 8444 kg with a coefficient of variation of 14%. The percentage of fat and protein had a smaller data spread (less than 3%). Significant differences were found between the AA and AB genotypes in terms of fat percentage (0.0374% higher in the AB genotype). No significant differences were observed in milk yield and total fat yield over 305 days of first lactation. There were no significant differences in the level of total protein and the percentage of protein.