Dynamics of the genetic structure of dairy cattle population in the Sverdlovsk region

By the beginning of the 21st century, the population of pedigree dairy cattle in the Sverdlovsk region was represented by the Black Pied breed, which was actively improved through the use of Holstein bulls. The resulting Holsteinization led to changes in the gene pool of the regional population, which this study aims to describe and analyze. Using GGP Bovine 150K and Bovine 50K DNA microarrays, we determined the genotypes of over 1,000 cows born between 2007 and 2022, belonging to nine agricultural enterprises in the Sverdlovsk region. Comparative groups included genotypes of Black Pied, Kholmogory, Tagil, Holstein, and Jersey breeds. Data analysis employed PCA, fastSTRUCTURE, and genetic differentiation assessment (F ST ). The results revealed that the vast majority of cows born in the Sverdlovsk region prior to and including 2014 exhibited genetic similarity to the Black Pied breed. Nevertheless, starting in 2015, cows born in the region showed greater genetic affinity to the Holstein breed than to the Black Pied. Genetic differentiation estimates (F ST ) between cows born after 2015 and Holstein bulls indicate the completion of the transition to the Holstein breed, driven by crossbreeding strategies. These findings propose a reference framework for breed identification in Black Pied versus Holstein cattle. A hypothesis linking herd gene pool characteristics to average milk yield per dairy cow was tested. Principal coordinate analysis based on the full set of genetic markers did not confirm this hypothesis. The observed differences in dairy productivity are likely attributable to environmental factors or genetic variations in specific genomic regions.