COMPARATIVE ANALYSIS OF THE PARENTAL INDEX OF BLACK-AND-WHITE BREED BULLS OF DIFFERENT GENOTYPES BY THE KAPPA-CASEIN GENE (CSN3)
The associative relationship of the genotypes of the Kappa-Casein gene (CSN3) of breeding bulls with their breeding value in terms of the milk productivity of female ancestors was studied. The studies were carried out on the basis of JSC “Breeding enterprise“ Barnaul ”of Altai Territory on a sample of 45 black-and-white bulls belonging to three lines - Vis Back Ideal 1013415, Reflection Sovering 198998 and Montvik Chieftain 95679. The polymorphism of the CSN3 gene in bulls of the studied lines is represented by three genotypes - AA, AB and BB and is registered only in bulls of the Vis Back Ideal 1013415 line. The BB genotypes are absent in Reflection Sovering 198998 and Montvik Chieftain 95679 lines. The dominant genotype of the CSN3 gene in the studied bulls is the AA genotype (57.8%). Bulls with this genotype had the highest PSI in milk yield (10,032 kg), amount of milk fat (422.8 kg) and protein (323.8 kg). The higher potential for fat and protein content in milk was in bulls with the desired genotype of Kappa-Casein BB - 4.26% and 3.44%, respectively. The differences obtained between the bulls of the studied lines according to PSI in terms of milk productivity except for milk yield (between the producers of the Vis Back Ideal 1013415 line with the AA genotype and the Montvik Chieftain 95679 line with the AA genotype for 1401 kg at p <0.05) were statistically insignificant. At the same time, the highest genetic potential in terms of milk yield (10267 ± 600.6 kg), the amount of milk fat (429.0 ± 29.84 kg) and protein (342.7 ± 26.75 kg) had bulls of the Reflection Sovering 198998 line with the genotype AB for the Kappa-Casein gene. The greatest genetic potential in terms of fat content was in bulls of the Montwick Chieftain 95679 line with the AB genotype for the CSN3 gene-4.44±0.037% and in terms of protein content in milk - in bulls of the Vis Back Ideal 1013415 line with the BB genotype (3.44±0.183%).