Relationship between alleles of gene BoLA-DRB3 and somatic cells amount in milk of Ukrainian black-and-white dairy breed

A significant genetic correlation between the indicator of the somatic milk cells amount (SCC) and intrama mmary infection has been established, making it possible to use it in breeding programs for reducing of mastitis in cows. Various studies demonstrated that resistance (susceptibility) to mastitis is genetically predetermined. Among the genes associated with diseases, special attention is paid to exon 2 of the gene BoLA-DRB3, which is quite polymor -phic. The aim of the study was to identify associations between alleles of the gene BoLA-DRB3 and SCC among cows of Ukrainian black-and-white dairy breed (N = 92). The RFLP-PCR method revealed 31 BoLA-DRB3.2 alleles. The relative risk index and the χ 2 test were used to establish a link between the allele frequencies and the SCC. Two alleles with strong association with low level of SCC (CI = 0.95): BoLA-DRB3.2*22 (P(A) = 0 . 06; RR = – 3 . 43; χ 2 = 3 . 84) and BoLA-DRB3.2*28 (P(A) = 0 . 076; RR = -4 . 14; χ 2 = 6 . 17)were revealed,. An additional check using the precise Fisher’s exact test controlled by Pearson’s contingency coefficient showed that only allele BoLA-DRB 3.2*28 can be used as a marker in connection with low SCC in cows of Ukrainian black-and-white dairy breed. The allele *28 as a SCC marker was revealed for the first time. Analysis of previous studies shows discrepancies between the results that link different BoLA-DRB3.2 alleles with SCC, obtained for different breeds and even within the same breed. In future, it is necessary to expand the research by increasing the research sample and determine the associations between the number of somatic cells not only in connection with allelic polymorphism, but also in connection with the genotypes of the BoLA-DRB3 gene. Interstitial application of the new antibacterial liposomal preparation has led to a decrease in the number of somatic cell cultures in the afflicted animals with subclinical mastitis of cows.