Factors influencing fairy productivity when milking barns

The paper highlights longevity  of industrial use of cows. The authors analyze criteria of dairy productivity during the first lactation, maximum lactation and lifetime of cows in relation to their linear belonging, heifers fertility in the highest lactation and the of the first successful insemination. The longer period of industrial use was observed in Montvik Chiftein cows (2.90 lactations), in offsprings of low-fertile cows (2.97 lactations) and in cows that were first successfully inseminated aged 15-18 months (2.95 lactations) . The indicators of lifetime milk productivity in Montvik Chiftein cows are higher in comparison with Vis Ideal cows and Reflection Sovereign cows: milk yield on 2322.1 (9.4%) and 1084.0 kg (4.4%) (P <0, 05) respectively, fat mass - on 0.02% (P <0.05), protein concentration - on 0.02 and 0.03% (P <0.01). The milk fat and protein obtained from Montvik Chiftein cows is higher  in comparison with the 1st and 3rd groups; fat - on 96.4 (9.7%) and 43.8 kg (4, 4%) (P <0.05), protein - on 76.6 (9.8%) and 37.5 kg (4.8%) (P <0.05). High milk yield produced by heifers (more than 10,000 kg of milk for the highest lactation) allowed the offsprings to take the leading positions in terms of milk productivity in the period of the first and maximum lactations. From offsprings of low fertile cows (less than 7000 kg of milk for the highest lactation), the researchers received more milk than from the cows of the 2nd and 3rd groups due to linger lifetime (219.9 (0, 9%) and 544.2 kg (2.3%)). The heifers, which were first successfully inseminated at the age of 12-14 months, differed from the cows inseminated at a later stage by higher milk yield    for 305 days of the first lactation – on 562.7 kg (6.5%) (P <0.001), milk fat and protein in milk - on 19.3 (5.6%) and 17.3 kg (6.4%) (P <0.001), respectively. The heifers  inseminated in younger age have reached their maximum productivity at, the age of 1.6 lactation. The cows, successfully inseminated for the first time at the age of 1518 months, had high parameters of lifelong milk productivity (P <0.001). According to the milk yield, this variation was 2,294.5 kg (9.5%), the fat mass of  milk - 0.04%, 99.3 kg (10.2%), milk protein - 69, 2 kg (9.1%).