Intra-linear selection and cross-line selection when creating highly productive dairy cattle herds

The aim of the research was to evaluate the compatibility of lines and improve on this basis the traditional selection methods for creating breeding herds in dairy cattle breeding. The results of the analysis showed that the best milk yield among the other lines were the first-born heifers (n=39) of the Holstein line Vis Back Idial (6441 kg of milk). The analysis of the results of the intra-linear selection showed that the best milk yield was also distinguished by the first-born heifers of the Vis Back Idial line - 6721 kg of milk. Analyzing the cross-line of the Vis Back Idial with other lines of the Holstein breed (MCH, RS, and PG), it should be noted that they are superior to their first-calf peers by 253-530 kg of milk. The first-calf cows, derived from the cross of the Montwick Miftaine line and the Reflection Sovering and Pabst Governer lines, also have some superiority over their peers. Thus, when improving breeding herds of dairy cattle, it is necessary to use both intra-linear selection and cross-lines, taking into account their compatibility.