Association investigation and gene expression in genotypes TNFα with somatic cell score in Holstein Dairy cattle

Mastitis is a very important economic disease in dairy cattle. The TNFα gene as a key gene involved with mastitis and its polymorphisms and expression was evaluated as well as its correlation with somatic cell score (SCS). The gene expression of bovine TNFα profiling in Holstein cattle was also assessed. For this purpose, one hundred Holstein lactating cows were selected based on their breeding values for milk production, fat and somatic cell scores. Then cows based on their residual values for somatic cell scores were divided into two resistant and susceptible groups and 5 ml blood samples were collected from each animal. Selective genotyping of two target groups of susceptible and resistant animals to mastitis was done using PCR-RFLP approach, and then statistical association study was taken between identified genotypes and phenotypes records. Then, gene expression profiling between resistance and susceptible groups was evaluated using Real time PCR method. Results at this research showed significant correlation between TNFα gene polymorphism and values residuals of SCS (P<0.01). Gene expression was difference between the susceptible and resistance groups which, can be indirectly reflect relationships between screen mutations and gene expression pattern. So that the highest gene expression was belonged to BB genotype. As the final message of the present study, AA genotype may play a role and associated with relative resistance phenotype to mastitis in the studied population.