Assessment of the effect of the Holstein breed genotype on the productive qualities of cows

Relevance . Holstein dairy cattle are being bred in the Sverdlovsk region, and its improvement is underway to select and select the best for further breeding, including by increasing the bloodline of the Holstein breed. The aim of the work was to assess the milk productivity of cows of the modern Holstein breed with different blood levels obtained and used in the conditions of the Middle Ural. Methods . To conduct the study in a typical breeding reproducer for the region, an analysis of changes in the productive qualities of cows and the duration of productive use, depending on the bloodline of the Holstein breed, was carried out. The dairy productivity of cows was assessed according to the periods of lactation activity – average, for 305 days and maximum lactation, as well as by lifetime milk yield. Milk yield — by control milking once a month. The fat and protein content in milk was assessed in an average milk sample once a month from each cow. Results. An increase in milk yield was found during the average lactation and for 305 days of lactation with an increase in blood supply according to Holstein. Moreover, for average lactation, this increase is observed until the Holstein level reaches 96.1%, and a further increase in blood supply led to a decrease in this indicator by 438.9 kg or 7.3%. Milk yield for 305 days of lactation increases with an increase in blood content to reach 96.9% blood content, which is explained by an increase in the genetic potential of animals. The indicators of maximum milk yield begin to decrease with an increase in blood supply from 96.1%, confirming the increased typing of animals according to productive characteristics and a decrease in the diversity of this trait in the herd. With an increase in Holstein blood supply, there is a sharp decrease in lifetime milk yield from 18701.5±357.42 kg (blood content 93.8%, group 1) to 10889.0±280.07 kg (blood content 96.9%, group 4), which corresponds to 41.8%. An increase in blood supply from 93.8 to 96.9% led to a decrease in the age of culling and, accordingly, the duration of productive use from 3 lactation to 1.8, that is, almost twofold. The research is exploratory and was carried out within the framework of scientific research at the Ural State Agrarian University (state registration No. AAAAA-A19-1191014000069).