Assessment of the effect of inbreeding on the productive longevity of dairy cattle

Abstract

When breeding dairy cattle, both heterogeneous and homogeneous selection is used. Assessment of the influence of the degree of inbreeding on the productive quality and duration of the productive longevity of cows. It was found that despite a slight increase in milk yield in inbred animals (by 93 - 378 kg depending on the degree of inbreeding and by 73 kg on average for the group of inbred animals), a decrease in the qualitative indicators of milk, the mass fraction of fat and the mass fraction of protein and a significant increase in live weight of cows (P≤0.05) obtained using inbreeding. There is a superiority of herd cows over the requirements of the standard for black and white breed by 2500 - 2947 kg in groups (on average by 2624 kg) in milk yield and by 0.31% in the mass fraction of fat in milk; for Holstein breed these results are slightly lower and amount to 1500-1924 kg (an average of 1624 kg) for milk yield. The greatest amount of milk and nutrients was obtained from inbred cows with moderate levels of inbreeding and outbred animals, due to an increase in the duration of productive use. With the age of the cows, their milk production practically does not change, remaining at a fairly high level. The use of closely related crossbreeding with a simultaneous increase in the blood level in the Holstein breed leads to a slight increase in milk yield and the duration of productive longevity by 0.2-0.4 lactation. In lifetime productivity, inbred cows with a moderate degree of inbreeding remain superior. Outbred animals are at second place.