The Analyse Of The Relation Of Polymorphism Of Bola-drb3 Gene And Subclinical Mastitis In Holstein Cows

Mastitis is a common kind of cow disease, which causes a heavy loss to dairy industry. Cattle's MHC, is also known as bovine lymphocyte antigen (BoLA). It is a genetic region which was composed of highly polymorphic loci on chromosome, which may be a high degree of expression, it plays an extremely important role in the animal body's immune system, and there is a close relationship between it and many diseases resistance and susceptibility. Therefore, the study of BoLA-DRB3 polymorphism associated with mastitis will has very important significance for us to prevent and control mastitis.In test one , mastitis survey was carried out with BMT method in 150 Mission dairy in Shihezi . In the survey of 574 cows, there were 306 positive cows , the prevalence rate is about 53.31%, the mammary district positive rate was 24.15% .In test two , 160 cattle were digested by BstYI and HaeIII with PCR-RFLP method, and relation beween BoLA-DRB3 gene polymorphism and mastitis was analysed. The results are as follows:The first, a 305 bp specific fragment was amplified by PCR5alleles, 9 genotypes were found respectively. The second, the mutation of Haeâ…¢restriction sites were deviated from the Hardy-Weinberg equilibrium (P <0.01), and the mutation of BstYI restriction sites reached Hardy-Weinberg equilibrium (P> 0.05).The third, genotype Haeâ…¢BB and gene Haeâ…¢B may be associated with mastitis susceptibility (P <0.01); genotype Haeâ…¢AA and gene Haeâ…¢A may be associated with mastitis resistance (P <0.01). The distribution of BstYI genotypes and gene frequencies in infected cattle and in the of health cattle was not significant differences (P>0.05), so it can not be determined whether the genes and genotypes were correlated with mastitis resistance or susceptibility.The forth, genetypes Haeâ…¢BB and BstYIBB were correlated with high SCC(P<0.01), Haeâ…¢AA was correlated with low SCC(P < 0.05).