Hutsulyak H. Productive qualities of lactating cows during a long period of infertility

In dissertation work presents the materials of research of the productive and reproductive qualities of Holstein cows in the conditions of industrial technology of milk production. A retrospective analysis of the herd and the experiments showed that the live weight of Holstein cows during exploitation has a dynamic character, increases from 594.4 kg in first-heifers to 673.0 kg in cows of the third lactation, and then decreases to 584.0 kg. At the same time, the realization of the genetic potential of the milk productivity of cows increases until the fourth lactation and is, in terms of 305 days, an average of 9575.2 kg (9391.5 kg of 4% milk), after which it decreases to a level of 9325.8 kg (9171.8 kg of 4% milk). Such dynamics of the main characteristics indicates some physical and physiological depletion of animals by intensive exploitation technology.