Introduction. The formation of dairy herds of breeding farms occurs, among other things, under the influence of the used bull-producers. Depending on the variety of bulls selected for consolidation and the intensity of their use, the herd acquires a certain genetic and phenotypic homogeneity, which affects the productive and breeding qualities of animals. The purpose of the research is to study the genetic potential of bulls used as producers on the breeding stock of Ayrshire cattle bred in the conditions of the Republic of Mari El. Materials and methods. The research was carried out in ZAO “Mariyskoe” of the Republic of Mari El. The research object was dairy cattle of Ayrshire breed. Research results, discussion. In the herd of Ayrshire cattle in ZAO “Mariyskoe” in 2017‒2022, daughters received from 13 producer bulls were producing. 81.8 % of the bulls on the list were recorded in various volumes of state tribal books, and three bulls were rated in Canada and had high indices of tribal value, LPI. Nine bulls were rated in Russia. Producer bulls, whose biological products were used to inseminate the uterine stock of Ayrshire cattle, were characterized by a high genetic potential for productivity: by milk yield from 7479 kg to 13517 kg, by mass fraction of fat ‒ from 3.83 % to 4.8 %, by protein ‒ from 3.2 % to 3.6 %. Analysis of the dairy productivity of bulls’ daughters showed that the descendants did not fully realize the genetic potential obtained from the fathers. The daughters of Landscape 103846246 had the highest milk yields. Conclusion. As a result of research, it was found that the Ayrshire bulls used as producers in the cattle herd of ZAO “Mariyskoe” had a high genetic potential. However, the milk productivity of the daughters of the studied producers was lower compared to the indicators of the maternal ancestors of the bulls, which seems to be associated with the influence of the maternal heredity of the cows.