The stated results of using outbreeding and inbreeding in a selection of cattle of the Ukrainian Whitehead breed, which belongs to the local population and is preserved only in one breeding herd. It was revealed that animals obtained from related breeding are characterized by a sufficiently high level of productivity and normal reproductive qualities. Although outbred and inbred heifers in the process of growth from birth to 18 months of age differed somewhat from each other in live weight, the difference was not statistically significant. In different periods of growth, both outbred and inbred animals had an advantage, indicating the possibility of improving the trait by purebred breeding methods. The absolute increase in live weight of experimental heifers on rearing was: Group I – 295 kg, II – 289 kg, III – 298 kg, IV – 308 kg and V – 293 kg without a statistically significant difference between the groups, which made it possible to conclude that there was no inbred depression when breeding cattle of a given herd through a related selection of parental pairs. It is recognized that the selection of calves to increase their live weight at birth will not have a positive effect on the trait during the growth of animals, as evidenced by the correlation between them.
As a result of the study of reproductive ability, the expediency of obtaining and using inbred cattle in a herd, which was inseminated almost a month earlier than outbred, was proved. Between outbred and inbred cows, a significant differentiation of milk yield for the first – third lactation was found, without a significant advantage of animals obtained by one or another method of purebred breeding. According to the first lactation, the highest milk yield was observed in cows of the close inbreeding group (group V) – 4501 kg, which exceeded the outbred ones by 150 kg and the lower inbred ones (groups II-IV) by 191 – 633 kg. Inbred cattle with distant, moderate and close degrees of inbreeding at the second lactation had from 4629 kg to 4719 kg of milk, with the highest rate in cows of a moderate degree of inbreeding, while outbred cows produced only 4582 kg. Cows of a moderate degree of inbreeding had the highest milk yield in the third lactation – 5204 kg and the lowest – 3897 kg of the group of a close degree of inbreeding. Outbred cows for this trait were superior only to individuals of the group of close inbreeding. The results of a comparative analysis of economically useful traits of outbred and inbred cows and heifers of the Ukrainian Whitehead breed indicate the possibility of using a related selection of parental pairs in a herd to increase the efficiency of interbreeding selection, replicate the hereditary traits of the ancestor and preserve the disappearing domestic breed of cattle.
Population Studies from Parish Registers: A Selection of Readings from Local Population Studies