Milk productivity of black-and-white cows depending on the linear affiliation

The availability of natural and high-quality dairy products for the population is a primary problem. Milk and dairy products contain all the nutrients a person needs. The high demand for dairy products implies an increase in their production with an increase in quality. The purpose of the research was to study the features of dairy productivity of cows of the Bis Back Ideal 1013415 and Reflection Sovereign 198998 lines. As a result of the conducted studies, it was found that there were no significant differences between the lines in milk yield for lactation and milk yield for 305 days of lactation, however, there is a tendency for higher milk yields in cows from the Reflection Sovereign 198998 line, which, according to absolute indicators, had higher milk yields, which is confirmed by the average daily milk yield for lactation. Cows from the Vis Back Idial 1013415 line (Group II) had significantly higher milk quality indicators (P≤0.05). In cows of group II (Vis Back Ideal 1013415 line), the biological efficiency of the cow (the amount of milk powder for every 100 kg of live weight per lactation) was 233.7 kg. This is higher than that of Group I cows (Reflection Sovereign line 198998), by 3.5 kg or 1.5% more. Lactation curves turned out to be quite stable, single-vertex and stable. In both groups, there is an increase in milk yield in the second month of lactation, its stabilization until the third month, and then a gradual decrease until the end of the studies. Thus, belonging to the line has an impact on the indicators of dairy productivity of cows. The diversity of traits, especially by milk yield in the groups, turned out to be quite large with a coefficient of variability from 13.4 to 22.9%, respectively, by groups. The milk obtained from the cows of the Vis Back Ideal 1013415 line turned out to be more biologically valuable.