Milk productivity of cows-daughters from different bulls

The results of researches of signs of milk productivity of the cows from different bulls for the first, second, third and higher lactations are presented. Studies were conducted on Black-and-White cattle (n = 1981) at Private Joint Stock Company “Plemzavod Styepnoy” Zaporizhia Oblast. There was studied the duration of lactation, milk yields of full and 305 days of lactation, fat and protein content in milk, quantity of milk fat and milk protein of descendants of different parents on the basis of a retrospective analysis of data for the period from 2004 to 2017 (the management program of the dairy herd “Uniform-Agri”). It was established that bulls have a significant impact on the formation of milk productivity of cows. Daughters of E. Naitinhel 683403608 had the longest duration of the first, second and higher lactation and descendants of N. Ardent 137922325 of the third one. Daughters of the bull G. Dzhungl 7816598 were the best by the milk yield of the full first and higher lactation, daughters E. Naitinhel 683403608 for the full second, and daughters of N. Ardent 137922325 – for the third. For 305 days of lactating there was observed a significant level of intergroup differentiation for the number of milk yield, milk fat and milk protein and much less by the amount of fat and protein in milk. For the first 305 days of lactation daughters of bull L.H.F. Bay 66821678 (10188.0 ± 377.12 kg) were characterized by the highest milk yield, and daughters of F. Gailuron 103356429 (correspondingly 11028.8 ± 30619; 11643.3 ± 590.20 and 10311.7 ± 382.07 kg) for the second, third and the highest lactation, with both bulls belonging to the line R.O.R.E. Eleveyshn 1491007. For 305 days of the first lactation descendants of the bulls V. Silas 7419933 (7003.5 ± 317.79 kg) from the line H.H. Starbak 352790 had the lowest milk yield, daughters of E. Naitinhel 683403608 (7633.0 ± 182.18; 7605.8 ± 224.58 and 8491.7 ± 185.42 kg respectively) from the line R.O.R.E. Eleveyshn 1491007 by the second, third and highest lactation. Detected by comparison of group average conditionality of phenotypic variability quantitative characteristics of the milk productivity of cows derived from different parents was confirmed by the dispersion analysis conducted by us. The most significant influence of bulls were made on the milk yields of daughters for the first-third lactation (12.9–16.8%), lower – for the amount of milk fat (12.4–15.6%) and milk protein (12.2–15.8%) and even lower – for the content of fat (2.5–4.2%) and protein in milk (3.7–6.6%). It should be noted that the effect of the bulls on signs of milk productivity for the lactation under study in their daughters in almost all cases was reliable (P & lt; 0.05–0.001) except for the fat content in milk for the first lactation and fat and protein – for the second and third lactation.