Milk productivity of first-calf heifers depending on the line and age of the first insemination

Abstract

Relevance. One of the key types of raw materials that ensure the food security of Russian citizens is milk. To obtain it, dairy cattle are used, including Holstein, created by absorbing the breeding stock of domestic black-and-white cattle by bulls of the Holstein breed. The study of economically useful qualities of a new genetic formation of dairy cattle in the Middle Urals zone is of both scientific and practical interest.Methods. The aim of the work is to evaluate the milk productivity of Holstein cattle depending on the age of the first insemination, taking into account the linear origin.Results. As a result of the research, certain features were established that, in our opinion, are associated precisely with the origin (depending on the age of insemination, the animals are divided into 4 subgroups). So, in the group of heifers of the line Reflection Sovering 198998, the same trend of change in milk productivity depending on the age of the first insemination, as well as the average for the herd. The first heifers with the age of the first insemination up to 14 months had the highest productivity (p ≤ 0.05 between the 1st and 3rd groups in favor of the 1st). In heifers of the Vis Back Idial line, on the contrary, the highest milk yields were in animals inseminated for the first time at the age of more than 18 months. They have the highest milk yields compared to cows from other lines. The superiority ranged from 700 (Reflection Sovering line) to 2275 kg (Montwick Chieftain line) or 7.6–24.9% for the highest milk yields (р ≤ 0.05–0.01). Among the animals of the line Montvik Chieftain 95679 had the highest milk yield of first-calf heifers inseminated at the age of 14 months. They outperformed cows with other periods of insemination by 886–891 kg (р ≤ 0.05).