Продуктивное долголетие коров черно-пестрой породы в зависимости от возраста первого осеменения и уровня удоя за первую лактацию

Abstract

The productive longevity of dairy cows are affected by many genetic and paratypic factors. An impact of the heifers age at first insemination and the level of milk production in the first lactation on the duration of economic use. The research carried out on the herd of Ob type cows of black-motley breed of Experimental Farm “Prigorodnoe” of Altai Kray. The indicators of 864 cows, which dropped out of the herd from 2010 to 2015, were analyzed. Maximum duration of economic use in lactation was installed in cows, inseminated at the age till 18 months.(6.1 lactation) and from 18.1 to 20 months (5.8 lactations). Cows, inseminated at the age of 26.1 months and more, were used in the herd least - 3.3 lactation. The highest lifetime of milk yield (32 745 kg) was obtained from cows with the age of the first insemination from 18.1 up to 20 months. A correlation analysis revealed a significant effect on the duration of the economic use of the age of the first fruitful insemination of cows, the month and the level of milking cows in the first lactation. The greater the age of the first ful insemination of cows and milk production level of cows during the first lactation, the less the duration of their economic use (respectively r = - 0.28 in the way of p <0.05 and r = - 0,45, p <0.001). The magnitude of life milking yield of cows significantly affects the duration of the economic uses of in lactation (r = 0,89, p <0.001) and less significantly, but significantly, the highest yield of milk per lactation (r = 0,30, p <0.01). It was found that the lower the milk yield of cows during the first lactation, the greater the duration of their economic use in lactation, lifetime milk yield, milk yield per day of life, the yield of milk fat, less than the length of service- and calving periods and the higher the ratio of reproductive ability.