The study was performed on retired Ayrshire cows (n = 4,708 heads) with at least the first calving. The distribution of heifers by the value of CSP0–10 corresponded to the normal distribution, therefore, animals by the value of this trait, taking into account the arithmetic mean (731 g) and the standard deviation (83 g), were divided into five groups. The value of CCP0–10 increased from the first group (558 g) to the fifth (889 g). It has been established that the value of CCP0–10 affects the age of physiological maturity, livestock safety indicators for the first (PS-1) and third (PS-3) lactation, and milk productivity for the first lactation. The highest safety of livestock was found in cows of the fourth group – 86.7%, the lowest in the first – 74.3%, which is 12.4% less (P ˂ 0.001). In the groups with an increase in CCP0–10, there was a decrease in the age of the first fruitful insemination, an increase in body weight and milk productivity over 305 days of the first lactation. Cows of the fifth group showed the highest milk productivity and live weight after the first lactation.: milk yield – 7893 kg, mass fraction of fat – 4.29%, milk fat – 338 kg, mass fraction of protein – 3.48% and live weight – 589 kg, which is 502 kg, 0.26%, 41 kg, 0.09% and 65 kg, respectively, more than in cows of the first group (in all cases, P 0.001). During the analysis of variance and correlation, it was found that the influence of (η2) and the correlation of CSP0–10 on the development of economically productive traits decreases with the age of cows. According to the results of the analysis, it was revealed that SSP0–10 at the level of 776–855 g contributed to the formation of large, highly productive animals, which were distinguished by better livestock safety, dairy productivity and higher indicators of productive longevity
Keywords
dairy cattle breeding, repair heifers, average daily growth, livestock safety, dairy and lifelong productivity, Ayrshire breed