Efficiency of dairy cattle breeding on the main features of productivity

Improving the productivity of cattle by breeding methods requires constant monitoring of the genetic situation in breeding herds, and therefore the evaluation of animals on the main economic useful features. Given that the cattle under the control of herds of research farms of NAAS network should be characterized by high productivity rates that are persistently inherited in subsequent generations and determine the genetic progress of the breed, we were tasked with evaluating cows of different breeds for dairy productivity and reproductive capacity for breeding system breeding. The studies were performed on cows of 6 breeds: Ayrshire, Holstein, Ukrainian Brown Dairy, Ukrainian Red Dairy, Ukrainian Red-and-White Dairyand Ukrainian Black-and-White Dairy. The productivity index of 8624 cows from 28 studs of NAAS research farms was included in the study. The average hope of herds of cows for 305 days of lactation and first-born cows, the amount of milk fat in milk of cows, the age and live weight of calves at the first fertile insemination, and the yield of calves per 100 cows were investigated. Among the tested breeds, which are bred in the herds of the experimental farms, the highest dairy productivity was characterized by the blood of the Ayrshire breed, the average hope of the herd was 6948 kg, and the first-born cows – 6826 kg. The cows of the Holstein breed of 4415 kg in average on a herd differed rather low milk productivity. The amount of milk fat in the milk of cows of the studied breeds was consistent with the value of their milk yield and fat content and was of the highest importance in the Ayrshire breed, confirming its high milk fat content. The earliest age of the first fertile insemination was characterized by heifers of Ukrainian Brown Dairy and Ukrainian Red Dairy breeds, respectively, 507 and 510 days. At the time when the average age of heifers at the first insemination of all the studied breeds under the control of the stud farms was about 18 months (536 days). The average live weight of the experimental animals at the time of their first fertile insemination was 380 kg and ranged from 393 kg in heifers of Ukrainian Black-and-White to 360 kg – Ayrshire breed, but for most herds the live weight did not correspond to the age of the animals according to the breed standard . The hope of first-born cows of Ukrainian Red-and-White Dairyand Ukrainian Black-and-White Dairy breeds was positively correlated with the amount of milk fat (r = + 0.966… + 0.988), and the age of first insemination had a positive effect on the reliability of first-born (r = + 0.576… + 0.976). Should be considered when choosing the timing of the first fruitful insemination of heifers in herds of these breeds. In general, a comparative analysis of dairy productivity and reproductive capacity of cows of 6 breeds of 28 herds of experimental farms showed an increase in dairy productivity of cows during the year, in some breeds studied significant, and not significant, but the deterioration of the reproductive capacity of cows of most breeds, which indicates the efficiency of cows towards improving cows' milk productivity.