THE GENETIC CONDITIONALITY OF THE ECONOMICALLY USEFUL TRAITS OF THE COWS OF UKRAINIAN BLACK-AND-WHITE DAIRY BREED
Authors: Shuliar A. L. , Shuliar A. L. , Omelkovych S. P. , Tkachuk V. P. , Andriichuk V. F. 
Published: November 2020

The intensification of dairy cattle selection determines the need of the systematic evaluation of animals in herds and populations on the main economically useful traits. They have an integrated origin and are controlled by significant groups of factors (genetic, physiological, technological and environmental). In dairy herds, the influence of such genetic factors as belonging to the breed and intrabreed types, the conditional blood share of improving breeds, the linear belonging, the family belonging, the origin by father is realized in the phenotypic performance of economically useful traits of animals with the simultaneous significant influence of environmental conditions.

Among the hereditary factors, that determine the level of intergroup differentiation by the main selected traits, are significant the origin by father and the linear belonging. In addition, the world gene pool of the Holstein breed has an impact on the heredity of the Ukrainian black-and-white dairy breed, which requires constant monitoring of breeding groups of animals in different herds.

Based on this, the aim of our research was to study the genetic conditionality of the economically useful traits of the cows of Ukrainian black-and-white dairy breed, that is, the study of the influence of such genetic factors as the conditional blood share of Holstein breed, the origin by father and the linear belonging on these traits.

The research was conducted in the herd of Ukrainian black-and-white dairy breed of the private agrarian firm «Yerchyky» Popilnia district Zhytomyr oblast during 2015–2019. The study was carried out on the materials of the breeding and productive use of 766 first-calf cows and 497 cows which were disposed from the herd on different reasons. The reasons for their disposal were determined according to veterinary disposal acts.

The statistical data processing was done using the method of variational statistics. The power of influence of the conditional blood share of Holstein breed, origin by father and linear belonging on the phenotypic variability of economically useful traits of the cows was determined by One-Way-ANOVA.

The results of the study of the influence of genetic factors on the economically useful traits of cows of Ukrainian black-and-white dairy breed are presented. It was found that the power of the influence of the conditional blood share of Holstein breed, origin by father and linear belonging on the phenotypic variability of live weight, measurements and indices of body constitution was 0.4–17.6%; indicators of milk productivity of cows – 0.3–20.8%; morphologo-functional characteristics of the udder – 0.5–21.9%; parameters of reproductive capacity – 2.3–9.3% and lifetime use – 0.1–12.6% (P < 0.05–0.001). The factors of the origin by father and the conditional blood share of Holstein breed had a more significant effect on mass-and-metric parameters and indices of body constitution, and the influence of the linear belonging on these indicators was the smallest. Among the studied genetic factors the origin by father had significant effect on the milk productivity and morphologo-functional characteristics of the udder, while the smallest influence of the linear belonging was on the indicators of milk productivity, and the conditional blood share of Holstein breed had the smallest effect on the characteristics of the udder. Regarding the indicators of reproduction and lifetime use of cows, the effect of the studied genetic factors on them was distributed without any trends.

The prospect of further research is to study the influence of paratypic factors on economically useful traits of cows of the Ukrainian black-and-white dairy breed of the private agrarian firm «Yerchyky».