GENETIC REGULARITY OF THE FARMING USEFUL SIGNS IN ANIMALS OF THE UKRAINIAN RED-and-WHITE DAIRY BREED BY ABSORPTIVE CROSSING. CONDITION AND OUTLOOK
Authors: Krugliak A. P. , Krugliak O. V. , Krugliak T. O. 
Published: July 2023

The aim of the research was too investigate the peculiarity of the phenotypic manifestation of economically useful traits of cows of the Ukrainian Red-and-White dairy breed during the period of its genesis and different genotypes under the conditions of using absorptive crossing methods.
Material and methods of research. The research was on 116.4 thousand of cows of the Ukrainian Red-and-White dairy breed in 199 farms and on 1142 cows of Holstein breed in 5 farms carried out. The dynamic of the main productive and reproductive traits of cows of the Ukrainian Red-and-White dairy breed for the period of its genesis and comparative assessment of the phenotypic manifestation of economically useful traits of cows of different genotypes of the Ukrainian Red-and-White dairy breed under the conditions of using different crossbreeding methods was carried out.
The results of research. In process of the implement of the first selection program of the Ukrainian Red-and-White dairy breed (2003–2013), the negative influence of yield of milk on the reproduction ability and fat content in milk of cows has been established. Too decide this problem, new methods of selection and artificial insemination of cows by semen of proven bulls for the complex of traits native selection was introduced. The liquidation of the state value of bulls in the Ukraine make the selection of the Ukrainian Red-and-White dairy breed bulls, what has absorptive crossing of the Ukrainian Red-and-White dairy breed by Holstein bulls (genotype - 96.87% and higher for the Holstein breed) promouted.
Statistically not significant relationships between the increase the conditional part of Holstein blood in cows over 93.75% and the level of milk productivity were established. Cows with an increased conditional part of Holstein blood of 96.87% and above, obtained by absorption crossbreeding and assigned to the Holstein "native selection", in terms of 305 days of the last completed lactation, lagged behind their analogues of the Ukrainian Red-and-White dairy breed on average by 26.0 kg of milk and outweighed them by 2.0 kg of milk fat. The level of milk productivity of cows of both breeds, in three breeding farms was practically the same. According to the indicators of the reproductive ability of the Holstein breed cows of "domestic" selection (genotype - 96.87% and higher for the Holstein breed), they were significantly inferior to the analogues of the Ukrainian Red- and-White dairy breed. The duration of the service period for the group of cows of the Holstein breed of "domestic" selection was 140.4 ± 15.30 days, which is 16.4 days longer compared to this indicator for cows of the Ukrainian Red-and-White dairy breed. The yield of calves per 100 cows of the Ukrainian Red-and-White dairy breed was 85.2 ± 1.98% and exceeded this indicator of Holstein cows of "domestic" selection by 4.6 calves. The direction of further improvement of animals of the Ukrainian Red-and-White dairy breed was determined.
Conclusions.

The genetic potential of dairy productivity of cows of the Ukrainian Red-and-White dairy breed (genotype 62.5–93.75% of Holstein blood) is 10.0–11.0 thousand kg of milk, high reproductive ability (116 days off and 88–90 calf per 100 cows).
The absorptive crossing the cows of the Ukrainian Red-and-White dairy breed by Holstein bulls, on the level of feeding, which is in most dairy plants of the Ukraine, das not ensure of the increasing of economically useful traits of cows.