Reasons for the culling of breeding stock of holsteinized Black-and-White cattle depending of age

Abstract

The improvement of dairy cattle in the Russian Federation is currently being carried out through the use of the gene pool of the world’s best dairy breed as Holstein. This had a positive effect on the dairy productivity of cows, but led to a decrease in productive longevity. Therefore, the reasons for culling the breeding stock of dairy cattle depending on the part of blood of Holstein breed are of considerable interest. At the same time, it is relevant to study the duration of use of cows in herds with industrial exploitation technology. The purpose of the research was to analyze the reasons for culling holsteinized cows of Black-and-White cattle, depending on age. The data on the reasons for culling cows, taking into account the age of cows in lactations have been presented in the article. It has been established that the most common causes of culling are pathology of metabolism, reproductive system, digestive system, selection criteria (mainly barrenness) and pathology of the mammary gland. The age of cows has a certain influence on the level of culling, which increases in full-aged cows. Young cows drop out of the herd due to the pathology of the reproductive system, breast, metabolism, barrenness and injuries. Thus, it was found that the dynamics of metabolic disorders diff ered rhythmically, then increasing, then decreasing from lactation to lactation. This is especially clearly seen from 1 to 5 lactations, and then this dynamics tended to decrease, slightly increasing by 8 lactation. In general, for culled animals the largest culling from the herd was observed for full-aged cows 65,0 % of the total number of culled, including for 3 and 4 lactations 41,0 %. Culling of young cows for 1 and 2 lactations was 35,0 %.