INFLUENCE OF THE FATHER’S GENOTYPE ON THE PRODUCTIVE LIFESPAN OF HOLSTEIN COWS

Abstract

The profitability of dairy cattle breeding significantly depends on the productive lifespan of cows, since the greatest costs occur in the first 2 years of life. As a result,
if the longevity index does not exceed 1–1,5 lactations, then the first cost of production is
higher than in long-lived cows. However, the intensification of production has significantly
reduced the time of economic use of dairy cattle. For decades, the population of dairy cattle in
Stavropol has been updated due to the import of heifers. A peculiarity of Western breeding is
the use of a large number of bulls in the selective breeding process. The purpose of the research presented in the article was to analyze the timing of economic use of Holstein cows,
taking into account genealogical and genetic affiliation. In 2022, in LLC “Chapaevskoe” of
the Stavropol Territory, 3 genealogical groups were formed taking into account linear affiliation, in each of which genetic groups belonging to specific servicing bulls were identified
(n=15). The terms of economic use, productive life, causes of replacement and profitability of
production were studied. The average age in the genealogical groups was 3,2-3,3 lactations.
Lifetime milk yield was higher in Vis Back Ideal cows and amounted to 28 204,31 kg, which
is 2,9–5,1% more than in their herdmates. The main reasons for the retirement of Holstein
cows in the studied population were: infertility and diseases of the reproductive organs, noncommunicable diseases, zootechnical defect and various infections. For the reason of zootechnical defect, cows with low productivity were culled. Infertility was caused by various
diseases. Hypo-ovarionism, uterine subinvolution, ovarian sclerosis and atrophy were most
often diagnosed. In general, the profitability level for the lines amounted to 38,11%. Thus,
significant differences on the studied factors were not established, which indicated the consolidation of economically useful traits in the lines of Holstein cattle, which steadily were transmitted to the offspring.