Dairy productivity of cows-daughters of Holstein bulls-producers

Relevance Currently, more than 65% of the dairy cattle in the country are represented by the Holstein breed. During its breeding, great attention is paid to the quality of breeding bulls.The aim of the work was to assess the influence of a breeding bull on the productive qualities of daughters.Methods. The research was conducted in the conditions of a typical agricultural enterprise for the production of milk — a breeding reproducer for the breeding of Holstein cattle. The material and data for comparison were the database of the IAC “SELEX-Dairy Cattle”, the results of our own research. Milk yield for 305 days of lactation was taken into account for lactation, MJ and MDB in milk. Dairy productivity (milk yield, fat content, protein content in milk) of cows was controlled by control milks. The fat and protein content was determined in the average milk sample from each cow once a month.Results. As a result of the research, it was found that, based on the BLUP assessment, the evaluated breeding bulls were milk yield improvers compared to other evaluated bulls. The largest amount of milk was received from daughters of Dagger bull — 10,039.9 kg, which is more than from daughters of other bulls, by 772.6 kg, 721.8 kg and 660.6 kg of milk, or by 7.7%, 7.2% and 6.6%, respectively. The differences were unreliable. The relationship between the indicators of productive qualities varies according to a general pattern inherent in cattle: with an increase in milk yield, there is a decrease in the quality of milk: the mass fraction of fat, the mass fraction of protein in milk. Conversely, with a decrease in milk yield, an increase in these indicators is observed. The daughters of all breeding bulls had a dairy constitutional orientation, since they had high milk production coefficients — above 1,000 kg of milk for every 100 kg of live weight.