In the dissertation work a comprehensive study of the basic genetic and biological characteristics of animals based on live weight, milk productivity, duration of economic use, factors of formation of growth and development indicators, value of milk yield, chemical composition of milk, reproductive ability, individual indices of natural resistance, lifetime productivity, duration of economic use of the gene pool of brown breeds in the North-East of Ukraine was conducted.
In order to preserve the gene pool of Lebedinian breed, research was conducted on the quality of sperm production stored in breeding centers and gene pool banks, in which it was found that the average number of semen in the sperm dosages of long-term storage of Lebedinian breed is 1478.3 ± 467.6 million at their concentration of 5917.6 million / ml. In general, evaluated semen has been recognized as suitable for insemination of cows and heifers.
According to the results of a genetic study of sperm production of 12 Lebedinian bulls-producers for the kapa-casein genome (CSN3) the frequency of the desired genotype BB among the studied animals was 0.17, and the frequency of carriers of the genotype AA was 0.50. Frequency of carriers of the heterozygous genotype AB was 0.33. The carrier frequency of the allele A in the tested animals is 0.66, which is almost twice as high as the allele B frequency of 0.34.
The micro-populations of Ukrainian breeds of the North-East of Ukraine, investigated by us, have demonstrated a generally low genetic diversity in the presence of differences between them. Reduced levels of genetic polymorphity and heterozygosity, especially in samples of Sumy intrabreed type animals of Ukrainian black and white dairy breed, Ukrainian black and white dairy breed and Lebedinian breed, potentially create threats to reduce genetic diversity, loss of unique alleles and increase inbreeding in subsequent generations. The composition of the single cluster includes breeds, closely linked by historical ties – Shvits and Lebedinian, which are linked to a common cluster. Therefore, Shvits breed, which was used in the construction of the Lebedinian breed, including its original OBV branched, can be added to the process of preserving the Lebedinian breed. The probable influence of belonging to the breed on the individual resistance index of the studied cows is established. In order to preserve the gene pool of brown cattle, a method of preservation and further improvement of the Lebedinian breed gene pool by the population of reciprocal reproduction has been developed. The use of German and Swiss bulls-producers will expand the genealogical structure of the Lebedinian breed and avoid unwanted inbreeding in the further work with bulls-producers, whose sperm is stored. It was established that cows of gene pool herds of Ukrainian brown milk breed are characterized by a sufficient level of milk yield (3665-4566 kg), with the highest productivity of cows observed in animals of the fifth lactation – 4658 ± 170 kg. The origin of the father probably influenced the amount of milk yield (2x = 26,6), the amount of milk fat (2x = 29,5), the amount of milk protein (2x = 23,7). The level of qualitative indicators of dairy productivity in animals of Ukrainian brown milk breed is differentiated by gene pool farms. The gene pool mothership of the Ukrainian brown milk breed was marked by low fertility, as indicated by the fertility index (35.2-36.2), the reproductive capacity (0.88-0.90). According to the results of the conducted researches, it was found that the indicators of life expectancy, economic use and lifetime productivity of cows of Ukrainian brown milk breed were probably influenced by heredity by Shvits breed. The most popular among all groups of animals, according to the indicators of life expectancy, economic use and the coefficient of economic use, were domestic genotypes: groups of animals with the heredity of Shvits breed up to 50%. In terms of lifetime milk yield and yield of milk fat and milk yield in one day of life were animals with hereditary of Shvits breed – from 75.1 to 87.5%.
A complex of breeding and biotechnological methods for obtaining in vitro embryos of domestic breeds of cattle has been applied. The level of formation of zygotes and the division of cow embryos was 33.3% (3 embryos out of 9 OKK). Such approaches ensured one embryo of the preimplantation stage of development suitable for the freezing procedure. The principal scheme of improvement and preservation of the Ukrainian brown dairy breed and a way of consolidation of its economic useful signs is offered.
