The level of milk productivity and reproductive ability of cows depending on the duration of the open days period

Abstract

The open days period is one of the components of the physiological cycle of the cow, during which it must be prepared for effective insemination. The duration of this period as a production indicator gives a general idea of the reproductive traits of the herd as a whole, and of each animal in particular. In order to increase milk production, it is possible to extend the open days period to obtain a longer lactation. Studies of this issue show that at the same time the dry period also extends and the average daily milk yield as the whole for lactation decreases. The purpose of the research was to determine the level of milk productivity and reproductive ability of cows depending on the duration of the open days period. The research has been carried out under the conditions in the APC “Emurtlinsky” in the Tyumen region, which is a breeding farm for the breeding of cattle of Holstein breed. It has been found that with an increase in the duration of the open days period from 93 days in the control group to 146 days in the experimental group the duration of barrenness was 3 and 56 days, respectively. It has been found that on the 1st day of milk yield per cow, the milk loss was 4,9 kg, and the absolute annual milk loss in the cows of the experimental group was in the range of 275 kg. The conducted studies suggest that with the increase in the duration of calving interval, there is the decrease in the milk yield of cows per year. The use of cows with the increase in the open days period above the norm recommended by specialists is unjustified. The increase in milk yield due to the lengthening of the lactation period is not effective, because it eventually leads to the increase in the number of days of barrenness and milk loss.