26 Випуск 32. 2020 Сільськогосподарські науки Issue 32. 2020 Agricultural sciences UDC 575.17:636.2:616.98 Olha Biriukova 1 PhD (Agriculture), Senior Researcher, head of the department of cattle breeding E-mail: irgt.spetsrada@ukr.net Tetiana Suprovych 2 Doctor of Agricultural Sciences, Professor Head of the Department of Animal Hygiene and Veterinary Support for the Cynological Service of the National Police of Ukraine Faculty of Veterinary Medicine and Technology in Animal Husbandry E-mail: suprovycht@gmail.com Mykola Suprovych 2 PhD (Techn.), Associate Professor Educational and Scientific Institute of Energy, Department of Physics, Labour Protection and Environmental Engineering E-mail: kokas2008@ukr.net Svitlana Laiter-Moskaliuk 2 PhD (Vet.), Associate Professor Head of the Department of Animal Hygiene and Veterinary Support for the Cynological Service of the National Police of Ukraine Faculty of Veterinary Medicine and Technology in Animal Husbandry E-mail: layter.moskalyuk1977@gmail.com Igor Chornyi 2 Assistant Professor Head of the Department of Animal Hygiene and Veterinary Support for the Cynological Service of the National Police of Ukraine Faculty of Veterinary Medicine and Technology in Animal Husbandry E-mail: chorniyigor78@gmail.com 1 Institute of Animal Breeding and Genetic, Chubynske, Ukraine 1 State Agrarian and Engineering University in Podilya, Kamenets-Podilsky, Ukraine FEATURES OF DIAGNOSIS OF NECROBACTERIOSIS OF COWS BY PCR- RFLP Abstract Molecular genetic markers can detect polymorphism at the DNA level. This feature determines the possibility of their widespread use in genetics and breeding. Alleles of the BoLA-DRB3 gene (exon 2) can act as such markers if a statically significant association between the disease and the allele is established. The presence of such DNA markers in the genotype of animals makes it possible to judge the likelihood of disease in postnatal ontogenesis immediately after the birth of a heifer, based on which we can conclude about the conditions of further use of the animal in the main herd. According to the results of studying the polymorphism of the BoLA-DRB3 gene in cows of the Ukrainian black and white dairy breed resistant and susceptible to necrobacteriosis, four "informative" alleles were revealed. Two of them *03 and *22 are associated with resistance, and the other two - *16 and *23 with susceptibility to necrobacteriosis. The presence of these alleles in the genotype of the animal is determined by testing performed by PCR- RFLP. The method is time consuming, labor intensive and costly. To simplify it, the following technique is proposed. Restriction fragments of alleles *03, *16, *22 and *23 for endocluases RsaI, XhoII and HaeIII have the