Kalchuk L. The improvement of reproductive and producing capacities of black-and-white cows under the conditions of Ukrainian Polissya

The object of investigation: Ukrainian black-and-white dairy cows and German black-and-white cows. Purpose and task of research: The purpose of research was to analyze reproductive capacities and duration of economic use of black-and-white cows of different origin, genotypes, lines and breeder offsprings, interraction among them and milk yield of cows for the further consolidation of the raised breed's Polissya population according to these characteristis. Methods of research: zootechnical, biometrical, economic. Theoretical and practical result: The thesis presents the results of investigations into the reproductive capacities and the indices of economic uses of cows of various origins (Ukrainian and German selection), Holstein cow genotypes with various heritage shares, lines and breeder offsprings. It has been established that black-and-white cows show lower indices of reproductive capacities and economic uses as compared to optimal parameters. The above characters influence milk yielding capacityand are poorly inherited. Ukrainian black-and-white dairy cows are characterized by better reproductive capacities, while German breed, by better economic uses, for they are more productive. The author analyses the causes of culling cows as well as the expediency of breeding Ukrainian black-and-white dairy cows with a share of Holstein heritage of 75 per cent and more (3/4-, 7/8 -blood relationship) under adequate feeding (45-55 metric centners of freeing units per average cow). The fields (sphere) of stock-breeding.