The age of retirement of cows from the herd, depending on genetic and paratypical factors

Abstract

Abstract. The purpose of the research is to study the age of retirement of cows from the herd, depending on various genetic and paratypical factors. Methods. The research was carried out according to the data of a black-and-white breed dairy herd of the Chelyabinsk region. The studied animals of different ages were divided into groups relative to the live weight at the first fruitful insemination, the age of retirement of mothers and bulls-producers of Holstein lines. The paper analyzes data for the period from 2003 to 2019 on 9247 heads of cows. The scientific novelty of the research lies in the analysis of genetic and paratypical factors affecting the increase in the age of retirement of dairy cows from the herd. As a result, it was found that the age of retirement of animals from the herd of the studied cows was 3.4 lactation. But only 29.0 % of cows were eliminated from the herd at the age of 5 lactations and older. At the early stages of economic use (before the 2nd lactation), animals were rejected due to diseases of the genital organs (1.5 lactation), respiratory organs (1.0–1.25 lactation), surgical diseases (1.5–1.8 lactation) and limb injuries (1.8 lactation). The shortest period of economic use, equal to 3.5 lactation, was observed in animals that were first fruitfully inseminated at the age of 18 months and older with a live weight of more than 400 kg. Long-lived mothers (older than 7 lactations) weakly transmitted their signs of productive longevity to their daughters, whose retirement age was 3.57–3.75 lactation. The daughters of the bulls-producers of the line Reflection Sovering 198998 had a longer period of use – an average of 5.1 lactations. Genetic and paratypical factors affect the age of retirement of cows. The study of this issue, as well as the competent application of the results obtained, make it possible to increase the period of production use of the dairy herd to 5 lactations or more.