The purpose of the research is to study the individual influence of the servicing bulls on productiveconstitutional characteristics of descendants. The integral assessment of Holstein servicing bulls was carried out. According to the rating of productive-constitutional signs of the cows-heifers, the milk yield improvers were the following bulls - Jacob 132065115 (+1726 kg), Chingis 982 (+1030 kg), Mistral 79325755 (+ 895 kg), Bosh 2733 (+ 30 kg). A positive impact on the descendants’ butterfat percentage had the Holstein bulls Simens 1869 (4.06% R≤0,001) and Reverse 2708 (4.03%, p ≤0.05). The high content of milk fat and milk protein are the distinguishing features of the daughters of the following servicing bulls – Kvint 1317 (4.27%, 3.26%, R≤0,001) and Modnik 3591 (4.07% R≤0,001; 3.20% R≤0,05). Milk body type is transmitted to descendants by the sires: Jacob 132065115, Chingis 982, Mistral 79325755 and Bosh 2733. A genotyping of the descendants by kappa-casein gene was conducted by PCR-RFLP method - 223 animals. The most usual is the cattle with homozygotic genotype AA of the kappa-casein gene - 82.1%. AB genotype is characterized by 17.5% of the animals, genotype BB - by 0.4%. The frequency of allele A is 0.908, allele B - 0.092. Holstein servicing bulls, assessed on the quality of the descendants, generally saturate the cattle population of the Ural-type with allele A of kappa-casein gene.