The frequency of occurrence of alleles of the beta-casein gene in different breeds of cattle

The article describes the data of scientific research on the frequency of occurrence of genotypes A1A1, A1A2, A2A2 and alleles A1 and A2 of milk protein beta-casein in cattle of various breeds, since 2014. Livestock in Pakistan, Italy, Greece, Croatia, China, Sweden, Mexico, Japan, Ukraine, Thailand, Brazil, Russia and Poland were considered. The data obtained on the territory of the Russian Federation is also described. The livestock of the Komi Republic, Bashkortostan, Stavropol and Krasnodar Territories, Arkhangelsk and Yaroslavl regions were considered. The most studied breeds in most countries are Holstein and Jaser. Holstein, Jersey, Sahiwal, white-headed Ukrainian, gray Ukrainian, hybrid (Sahiwal ? Holstein), gir, Guzera, Red, Polish, Hybrid (Holstein ? Zebu) breeds most often have the A2 allele and genotypes A1A2, A2A2. In cattle breeds in the territory of the Russian Federation, the A1 A2 genotype prevails.