Analysis of the reasons for culling Holstein cows depending on genetic factors

Relevance . When breeding dairy cattle of the Holstein breed, animal husbandry practices, along with the positive qualities of animals, face problems with reducing the reproductive function of cows and shortening the duration of the productive period. The purpose of the work is to analyze the reasons for culling dairy cows after the first lactation, depending on genetic factors (kappa casein genotype, lineage and breeding bull). Methods . The research was conducted in the conditions of a typical agricultural enterprise for the production of milk — a breeding reproducer for the breeding of Holstein cattle. The material and data for comparison were the SELEX Dairy Cattle IAC database, the results of its own research, veterinary documentation, and culling certificates. Results . As a result of the conducted research, it was found that the largest number of cows were eliminated due to diseases of the digestive system, and most often this is a metabolic disorder and in one case, scarring. Udder diseases, mastitis, came in second place. Limb diseases and limb injuries with sprains and ruptured ligaments were found in 24% of the culled animals, accounting for 12.7% and 11.3% of the cull, respectively. According to breeding criteria, 15.5% were culled. These are unproductive first-time heifers with a milk yield of less than 8,500 kg per lactation. Culling is mostly observed in the group of cows with a heterogeneous kappacasein AB genotype. 34.5% of the total livestock turned out to be such first heifers, and among them the cull was 27.6%. At the same time, the most stable genotype was the homozygous BB genotype. In the group of cows of the Reflection Sovering 198998 line, the main causes of culling were udder, digestive diseases and low productivity, and in the group of cows of the Ideal 1013415 line, digestive and udder diseases, which account for 50% of all causes.