Reproductive functions of cows and heifers of the Aberdeen-Angus Breed according to the calving season

Abstract

Abstract This paper presents indicators of reproductive functions of cows and heifers of the Aberdeen-Angus breed depending on the calving season in one of the farms of the Central Federal district of Russia. 1.729 calves were received, including calving of cows with twins, or 0.6%. Calves are produced in spring, summer and autumn in 2019. In the summer, the highest number of complex calving (8.0%), abortions and stillbirths (5.8%) was observed. In summer, heifers have more difficulty calving than in spring. Animals calve more easily and with fewer abortions and stillbirths in the autumn months. Quantity of abortions and stillbirths in this period were 0.9%, it is significantly less than the average for the year. Young bulls birth weight did not affect the further increase in live weight until 5 months of age. The live weight of bulls in summer and autumn is higher than those born in spring; it was found (p≤0.001). We recommend to strengthen control over feeding and body condition of cows and heifers with calving summer time and to provide them shelter from the heat. Calving of cows in the spring, autumn, and heifer only in the spring are the most prosperous.