PRODUCTIVE AND REPRODUCTIVE QUALITIES OF HOLSTEIN RED-AND-WHITE COWS IN THE KRASNOYARSK REGION

rm. ProductivityThe aim of the study is to evaluate the influence of the service period on milk productivity and reproductive qualities of Holstein Red-and-White cows. The object of the study was Holstein Red-and-White cows. Generally accepted zootechnical research methods were used: grouping, experiment, comparison, and analysis. Under the extreme climatic conditions of the Krasnoyarsk Region, the average milk yield of Holstein Red-and-White cows in general over 305 days of lactation is 8,512 kg with a fat content of 4.06 % and protein of 3.26 %. The average service period is 144 days, the calf yield per 100 cows is 75 heads. The main reasons for unsatisfactory reproductive function are gynecological diseases and infertility. The duration of the dry period corresponds to the zootechnical norm. The productive longevity of cows is 3.1 calvings. At the Berezovskoye breeding farm in the Kuragino District, cows of this breed produce 10,971 kg of milk. With an average service period of 123 days, 80 live calves per 100 cows are produced. The productive lifespan is 3.5 calvings. A significant advantage in milk yield was found in first-lactation cows with a service period of 40–60 days compared to the average milk yield for the herd (P ≤ 0.001). Increasing the service period to 134 days and the intercalving period to 418 days is accompanied by an increase in the insemination rate by 3.3 doses, a decrease in the reproductive efficiency coefficient from 1.09 to 0.87, and a decrease in the calf yield per 100 cows from 92 to 78 head. Obtaining fewer calves per year leads to significant economic losses. Based on the conducted research, recommendations have been made: to improve the milk and reproductive function of cows, we recommend disease prevention and treatment of the reproductive organs, which stabilizes the service period for cows at no more than 120 days, and for first-calf heifers – no more than 70 days.