Variability of linear conformation traits of the first-calf cows of Sumy intrabreed type of the Ukrainian Black-and-White dairy breed by different variants of selection of genealogical formations

In the aspect of research on cow's consolidation of Sumy intrabreed type of Ukrainian Black-and-White dairy by conformation, an estimation of first-calf cows was carried out using the linear classification method. The urgency of question was to study the influence on the conformation of cow methods of selection of sires using various combinations of genealogical formations. According to the results of the linear classification of sires' offspring of Valiant's parent line, there was a significant variability in the estimates of group traits within estimated combinations with maternal lines. The best-in-class of conformation traits characterizing the dairy type revealed the progeny of the first-calf cows received from intra-linear selection (84.2 scores) and cross lines of Valiant × S.T. Rokita (84.3 scores) and Valiant × Kheneve (84.0 scores). The worst traits of dairy type were expressed in first-calf cows, obtained as a result of cross lines of Valiant × Metta (82.2 scores), which with a significant difference inferior to peers obtained in the variants of intra-linear and interlinear selection, respectively on 2.0 and 1.1- 2.1 scores (P <0.05-0.001). The variability of estimates of the first-calf cows by group traits and final assessment in the variants of various linear combinations of the Matt's parent line with maternal Valiant, S.T. Rokita, Monfrech, Kheneve and Sjuprim differed significantly from each other and, in particular, from the level of offspring estimates obtained from internally - and interlinear selection of Holstein sires parental lines of Valiant with maternal Valiant, S.T. Rokita and Kheneve. In general, the best results in the system of 100-point evaluation by group traits and the final assessment of type were found in the variant of intra-linear selection of Valiant line and at its cross with maternal lines, the continuators of which were sires of Holstein breed. According to the assessment of descriptive traits, significant variability has been determined both within the groups of first-calf cows obtained from different interlinear combinations and within each estimated group. The best indicators of estimates of descriptive traits had cows in the selection variants which used sires of Holstein breed from the parent and maternal side.