Black and white cows’ productive qualities depending on their age

The aim of research was to study the productive qualities of black-and-white cows in connection with their age in the conditions of the Trans-Urals. The following tasks were solved: to analyze the terms of economic use in the herd of the breeding farm; to establish the main reasons for the disposal of animals; to study milk productivity (milk yield per lactation, mass fraction of fat in milk, amount of milk fat) in black-and-white cows; calculate the economic indicators of breeding black-and-white cattle. Research was conducted in a herd of black-and-white cows of the SPK Plemzavod Razliv, Ketovsk District, Kurgan Region. The object was black-and-white cows (n=215 heads). The average calving age in the herd of the SEC Plemzavod Razliv averages 2.7 calving. The main reasons for the retirement of black-and-white cows were diseases of the extremities (38 %), zoodefect (23.6 %) and difficult childbirth, complications (16.43 %) and other reasons. The amount of milk produced during lactation increased by the fifth calving – up to 7446 kg. The variability in the groups in terms of milk yield reached 30.7%, i.e. the herd is not aligned on this indicator and there were cows with a level of productivity significantly different from each other. The mass fraction of fat in milk increased from the first to the sixth calving from 3.65 to 4.08 % (P˃0.001). The variability of this trait is low, i.e. in groups, cows differ slightly in this indicator. Live weight at all age periods meets the breed requirements of the elite-record class. The variability of the trait is insignificant, almost all cows had the same live weight. The enterprise is profitable. The highest level of production profitability was 54 % in sixth lactation cows. When developing plans for breeding and selection, it is necessary to take into account the age (at calving), which affects the productivity of the cows. It is advisable to use cows on the farm for at least 5–6 lactations.