FERTILITY OF COWS UNDER HEAT STRESS

Abstract

In Olzha Agro LLP – a farm in Sadchikovskoye village and Saryagash LLP – a farm in Pereleski village, Qostanai region, carried out the effect of ambient temperature on the fertility of cowsfrom 2018 to 2020. The studies were conducted within the framework budgeting program “Improving the genetic potential of dairy cows 2018-2020”. The research material was Holstein cows aged 4-7 years, with the dairy productivity of 5000-9000 kg. The results of 313 cows from Sadchikovskoye LLP and 486 animal from Saryagash LLP were studied. We established the following: Average annual reproductive parameters in the farms for 2018-2020: Sadchikovskoye LLP: 1882 productive inseminations of cows, 419 calves, insemination rate – 3. Saryagash LLP: 3504 productive inseminations of cows, 1004 calves, insemination rate – 1.6. The lowest fertility occurred during the period of sharp deviations in ambient temperature. There were deviations in the production of estradiol and progesterone hormones in summer and winter periods after calving. A sharp increase in stress hormone Adrenaline was registered in summer and winter periods.
Key words: cows, stress, reproduction, calves, inseminations of cows.