Abstract. The article presents the results of using the genetic potential of the Holstein breed to improve black-and-white cattle. The purpose of the research was to analyze the influence of Holstein on the genetic structure of the herd and its milk productivity for the subsequent use of the results of the analysis in breeding and breeding work with animals. The objects of research were pure-bred animals of black-motley breed and crossbreeds of different genotypes from their crosses with bulls-producers of Holstein breed. Methods. The work used data from zootechnical and pedigree farm accounting, appraisal of livestock. Reliability of the origin of animals and the genetic structure of the herd was established by immunogenetic examination of the blood group systems (antigenic composition and alleles of the B-system). Results. It was established that under the same conditions of feeding and keeping, the milk productivity of the crossbred cows for the first lactation, depending on the blood content in the Holstein breed, was 97–550 kg more milk than pure-bred peers of black-motley breed. The most desirable for further breeding work are the genotypes of 5/8 and 3/4 blood animals. The use of Holstein bulls in this herd led to a significant change in the concentration of individual antigens and alleles of the B-system of blood groups in animals in comparison with the population of black-motley cattle. Scientific novelty. For the first time in the conditions of the Saratov region, studies were conducted to assess the population of black-motley cows and their Holstein crossbreeds by a set of economically useful traits and the efficiency of their breeding.