The genetic determination of the economically useful characteristics of the cows of ukrainian black-and-white dairy breed

Abstract

The economically useful characteristics of dairy cows depend on many genetic, physiological, technological and environmental factors. The modern cow population of Ukrainian dairy cows was formed by using the improved Holstein breed. The contribution of this breed into both the creation and the improvement of Ukrainian black-and-white dairy breed is reflected in its genealogic structure, as the prevailing part of the lines is of Holstein origin. That’s why the estimation of animals of different lines and the male descendants of the bulls in service according to the main economically useful characteristics is one of the most topical matters concerning the improvement of the rate of genetic potential realization of the animals under peculiar conditions as well as of the formation of highly productive and profitable dairy herds. As it follows from mentioned above, the goal of our research was to determine the effects of the bulls in service and their belonging to the line on economically useful characteristics of the cows. The material for the research was the information concerning the breed and productive use of the cows of Ukrainian black-and-white dairy breed on the breeding plant of the private agrarian firm (PAF) “Yerchyky” of Zhytomyr oblast, as well as the results of private research. To make an analysis there was used the information about the cows which were lactating for the period of 7 years when the feeding and keeping conditions were similar ones. For the purpose of the research on the genetic determination of economically useful characteristics of the cows of Ukrainian black-and-white dairy breed, it has been made an analysis from among the groups of paternity and linear belonging. The comparison of group middle young cows’ indices from different bulls in service and cows of various linear belonging has been made on the live mass, measurements and indices of body constitution, on milk productivity and morpho-functional characteristics of the udder as well as on their reproductive capacity. A considerable and highly reliable level of intergroup differentiation of cows of various linear belonging as well as of half-sisters by the bull has been determined on the economically useful characteristics. By means of single-factor variance analysis it has been determined that the paternity has a significant effect on the economically useful characteristics of cows that stipulates 0.71–21.92% of total phenotypic changeability of the characteristics being taken into account, whereas the belonging to the line was 0.54–12.70%. The study of the effects of paternity and linear belonging of cows on the parameters of their life-long productivity will be the perspective of the further research.