INFLUENCE OF BREEDING INTENSITY AND AGE OF PRODUCTIVE INSEMINATION ON THE MILK PRODUCTIVITY OF THE FIRST-CALF HEIFERS

Abstract

The analysis of the influence of the intensity of heifer breeding and the age of their
productive insemination on the productivity of the first lactation was carried out. The research
was conducted within the period from 2017 to 2020 on the basis of the breeding factory of
ZAO (closed joint-stock company) “Kalininskoe” in the Tver Region. The object of research
was heifer calves of Black Pied breed from 6 months of age to productive insemination,
heifers and first-calf heifers. Productive insemination of heifers was at 16 months, with a live
weight of 430 kg. The high level of feeding of replacement heifers under optimal conditions
of keeping and care fully ensures the maximum unleashing of the genetic potential of dairy
cows during the first lactation. Thus, the milk yield of first-calf heifers for standard lactation
was 7796 kg, while the total mass fraction of fat and protein was 543 kg. The first-calf heifers
had an average daily growth of more than 800 grams at the age of 6-12 months. The milk
yield for standard lactation was 7820 kg, which was 228 kg statistically higher than in their
herdmates with growth intensity of less than 800 g. We recommend farms to use intensive
breeding of replacement heifers of Black Pied breed with an average daily gain of at least
800g. This makes it possible to optimize the age and live weight of the first-calf heifers for
productive insemination in order to increase the productivity of the herd and the duration of
practical use of the animals.