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The aim of the study is to identify changes in genetic diversity at the BoLA-DRB3 gene exon 2 of Ukrainian Black-and-White dairy cows on the example of a breeding herd where, over the past decade, targeted selection for increasing Holstein bloodlines has been carried out to improve milk production. Changes in genetic diversity were determined by comparing the biodiversity of the experimental herd with Holstein populations. In three stages, blood samples were obtained from 391 cows of the Ukrainian Black-and-White dairy breed from the Kozatska Dolyna 2006 breeding farm, Khmelnytsky oblast, Ukraine. The allelic spectrum of the BoLA-DRB3 gene exon 2 was determined by PCR–RFLP. The study was carried out in stages: in 2008–2010 in the first population (maternal herd, n = 162), in 2014–2017 in the second population (daughter herd, n = 123), and in 2019–2022 in the third population (granddaughter herd, n = 106). For comparison, the study includes previously published data on Holsteins: United States (n = 1100), Canada (n = 835), Chile (n = 113), Argentina (n = 424), Bolivia (n = 159), Paraguay (n = 139), and Peru (n = 133). The high polymorphism of the BoLA-DRB3 exon 2 gene makes it convenient for analyzing the genetic diversity of cattle. The assessment by Simpson and Berger-Parker indices shows that the measured herd of Ukrainian Black-and-White dairy breed has more genetic diversity at the BoLA-DRB3 gene than the Holstein populations. The allelic structure of the studied herds, evaluated by the Pielu index and Buzas and Gibson evenness, is more uniform. Significant genetic diversity of the Ukrainian Black-and-White dairy breed is confirmed by the Shannon index and the effective number of alleles. Their values are significantly higher than those for all the considered Holstein cattle populations. In the time trend, a decrease in genetic diversity at the BoLA-DRB3 gene was found in Ukrainian Black-and-White dairy cows compared to Holstein cows. The linear forecast for the future period showed that the level of its genetic biodiversity will decrease at the current level of use of Holstein genetic material. [ABSTRACT FROM AUTHOR]

The Authors investigated polymorphism of the bovine BoLA‑DRB3 gene in connection with resistance or susceptibility to brucellosis of two Kazakh meat breeds, Auliekol and Kazakh Whiteheaded breeds, using PCR‑RFLP. In Auliekol cattle (n = 158), 22 alleles were detected in the brucellosis group, and 24 alleles were shown in the healthy group. BoLA-DRB3 alleles *3, *4, *19, *21 were more common in healthy animals, while Brucella‑positive cattle were more frequently carriers of alleles *7, *10, *18. In Kazakh Whiteheaded cattle (n = 146), 21 alleles were detected in infected and 23 alleles in healthy cattle. Alleles *3, *8, *21 significantly predominate in healthy cattle, while alleles *7, *11, *16 are typical for animals with brucellosis. This study identified BoLA-DRB3 alleles associated with genetic resistance (*3 and *21) and susceptibility (*7) to brucellosis; remarkably, resistance alleles are shared by two important meat breeds of Kazakhstan.

The results of the study of BoLA-DRB3 gene polymorphism in four domestic breeds are presented: Ukrainian black-and-white dairy (n = 293), Ukrainian red-and-white dairy (n = 131), Gray Ukrainian (n = 93), and Ukrainian white-headed (n = 49). The allele frequencies were determined based on the analysis of restriction fragment length polymorphism of the products of amplification of BoLA-DRB3 gene exon 2. Genetic profiles of the breeds were formed according to the following indices: allele (Pa) and genotype (Ga) frequencies, observed (Ho) and expected (He) heterozygosity, Wright fixation index (FIS), total (Na) and effective (Ae) number of alleles, and Shannon (I) and Pielou (J) efficiency indices. The maximal number of alleles were in the experimental sample of Ukrainian black-and-white dairy breed (Na = 37). In Ukrainian red-and-white dairy, Ukrainian white-headed, and Gray Ukrainian breeds, 31, 29, and 28 variants were found, respectively. In two breeds, the alleles with "no established nomenclature" were typed: Gray Ukrainian, jba, *jab, *jbb, *nad and *nda; Ukrainian white-headed, *nab, *mdb, *iab, *gbb, *fbd, *naa; their portion was 8.9 and 7.1%, respectively. The portion of "informative" alleles was: Ukrainian black-and-white dairy, 55.8% (seven alleles); Ukrainian red-and-white dairy, 60.4% (six); Gray Ukrainian, 69.9% (four); Ukrainian white-headed, 65.3% (seven). The expected heterozygosity and Wright index had the following values: Ukrainian black-and-white dairy, He = 0.942, FIS = 0.022; Ukrainian red-and-white dairy, He = 0.93, FIS = 0.032; Gray Ukrainian, He = 0.774, FIS = 0.041; Ukrainian white-headed, He = 0.927, FIS = –0.035. According to biodiversity indices, the greatest variability is typical for the Ukrainian black-and-white dairy breed (Ae = 17.2; I = 3.13; J = 0.6). The Ukrainian white-headed (Ae = 13.7; I = 2.93; J = 0.61) and Ukrainian red-and-white dairy (Ae = 11.5; I = 2.87; J = 0.558) cattle also had a high level of variability. A low level of biodiversity was found in Gray Ukrainian breed (Ae = 4.42; I = 2.21; J = 0.455). The analysis of BoLA-DRB3 gene exon 2 polymorphism demonstrated that the greatest genetic diversity is typical for the Ukrainian black-and-while dairy breed. According to genetic distances, the domestic breeds are combined in a single cluster with Holsteins, which indicates their genetic relationship. [ABSTRACT FROM AUTHOR]

At the current stage of genetic studies of cattle, more and more attention is being drawn to autochthonous breeds. Native cattle have a number of prominent phenotypic traits and have preserved unique genes and their combinations lost by modern commercial breeds, which would be valuable to use in selective programs. We surveyed polymorphism of the Ukrainian autochthonous Gray breed according to alleles of exon 2 of the BoLA-DRB3 gene. The uniqueness of the gene lies in the broad variability of its allele variants. Significant informativeness at DNA level is quite important for genetic studies. We surveyed allele polymorphism using the PCR-RLFP method on DNA isolated from 88 samples of blood of cows and 5 samples of sperm. We identified 28 alleles, of which 23 variants were nomenclature ones and 5 (jba, *jab, *jbb, *nad and *nda) were “without established nomenclature”, their share accounting for 8.9%. Four alleles *06, *12, *16 and *jba had a frequency above 5% and occupied 69.9% of the breed’s allele fund overall. The commonest allele was BoLA-DRB3.2*16 (44.1%). In total, we found 40 genotypes. Considering the significant dominance of variant *16, as expected, 5 genotypes with its inclusion occurred: *16/*16, *12/*16, *06/*16, *16/*24 and *jba/*16. It was present in the genotype of two out three studied animals. Parameters of heterozygosity, effective number of alleles, Shannon and Pielou indices indicate that Ukrainian Gray cattle are characterized by lowest level of genetic variability and biodiversity according to the BoLA-DRB3 gene compared with other breeds. Due to significant dominance of allele *16, the breed has no inbred motifs. We noted deviation toward increase in homozygosity without deviations from the norm of the distribution according to Hardy-Weinberg equilibrium. The obtained results will be used for genetic-populational programs with the purpose of improving the genetic potential of cattle breeds in terms of economically beneficial traits and diseases of cattle.

Expression analysis of immune response genes in the mammary gland tissues of both healthy and infected animals help to explain the genetic basis of differential immune response. This study was conducted to analyze the differential expression of MHC class II DRB3 gene, in mastitis-affected and healthy animals of indicus (Sahiwal) and crossbred (Karan Fries) cattle. Real-time PCR was performed on the cDNA synthesized from the RNA isolated from PBMCs of the mastitis and healthy animals. However, no significant difference was observed in the expression of DRB3 in the two populations. The results point towards polymorphism supposed to be playing major role in differential immune response, rather than the expression of DRB3 gene as far as state of udder health is concerned.

EBL is a disease of adult cattle caused by the retrovirus, bovine leukemia. It can manifest: aleukemic an asymptomatic form, with a normal number of B lymphocytes in the blood; a form of permanent lymphocytosis, with an increase in the number of B lymphocytes and finally a lymphoproliferative tumor presentation in the form of lymphosarcoma. The alleles of the genes of the Bovine Major Histocompatibility Complex (BoLA) have been associated with resistance and susceptibility to infectious diseases. The overall objective of this study was to associate polymorphisms of the BoLA-DRB3.2 gene, defined by the technique of polymerase chain reaction technique and polymorphisms length of the restriction fragment (PCR-RFLP), with resistance / susceptibility to leucosis in Holstein cows of La Pampa. It relied on a case/control design, for which blood samples were taken to 150 animals in 3 opportunities with intervals of three months each. The case group comprised animals that were positive in the immunodiffusion agar animals test (DIDA) and whose blood lymphocyte count was ≥ 10.000 linf/μl and the control group included cows that ware negative for DIDA and present < 10.000 linf/μl of blood. Fisher's Exact test and Odds Ratio (OR) of Woolf-Haldane were used to study the association between lymphocyte count and DIDA results with allelic variants. In 82 animals genotyped by PCR-RFLP, the DRB3.2*22 allele showed an OR = 5.332 (p = 0.0138) and DRB3.2*11 allele had a OR value of 0.11 (p=0.001) and were the most frequent in the control group and in the case group, respectively. These results would showed DRB3.2*22 allele and DRB3.2*11 allele a high risk of having leucosis (susceptibility) and low risk to suffer (resistance) respectively. The analysis of the relationship between alleles of the BoLA and resistance/susceptibility to leucosis could be improved with deep research on family lineages of dairy cows. [ABSTRACT FROM AUTHOR]