Influence of breeding process on variability of economic traits in dairy cattle

Abstract

The effectiveness of selective breeding is largely determined by trait variability which is formed under the specific conditions of existence of each individual animal population. The more variable a trait is, the faster its improvement can be achieved. In this regard, the research goal was to determine the effectiveness of selective breeding process in a Black Pied cattle population of by the indices of the main economic trait variability. The research objectives included the following ones: to calculate the breeding and genetic parameters of trait variability characterizing milk producing ability, reproductive ability and longevity of animals of different generations; to determine the degree of influence of genotypic factors on the studied traits; to evaluate the effectiveness of selective breeding according to the data of variant normal distribution for each trait. The research was carried out in 2023 at the Federal Altai Scientific Center of Agro-Biotechnologies (the Department - Bred Livestock Farm PZ “Komsomolskoe”, Pavlovskiy District of the Altai Region) in the dairy herds of different ages (1st, 2nd, 3rd lactations and older) in the context of three generations (birth years from 2005 through 2020). The research findings showed that when working with Black Pied cattle, a positive breeding effect was obtained in milk yield (15%), butterfat content (0.21-0.42%) and early maturity of animals (2.8 months), and a negative effect in milk protein content (-0.06% at an older age), service period (8.2-12.8 days), longevity (-1.8 lactation) and lifelong milk production (-8382.5 kg per 1 head). The variability of most traits decreased by 7.8-15.4%, and in terms of protein content - 2.2 times. As a result, the proportion of animals of interest for selective breeding decreased by 4.4-11.0%. The degree of the influence of the breeding process on the studied traits made 7.5-36.8%. The next stage of work with the population should include the mandatory use of servicing bulls to improve protein content and longevity. Among cows, more rigorous selection should be carried out regarding a set of traits.