Identification of polymorphism in the bovine interleukin-17A gene and its association with mastitis in Polish Holstein-Friesian cattle

Abstract

The main aim of this study was to identify the association between the single nucleotide polymorphism (SNP) in the bovine interleukin-17A (IL-17A) gene and mastitis resistance. Additionally, the connection between the identified polymorphism and the somatic cell score (SCS) was tested. Two hundred and six Polish Holstein-Friesian cows were genotyped using the PCR-RFLP method. One SNP mutation (c.126G > A) was identified within the coding sequence of the analyzed gene. Results of logistic regression analysis displayed no significant association between the IL-17A genotype and clinical mastitis occurrence (Wald chi-square test = 0.74; P = 0.69). The GLM analysis demonstrated that genotype also did not affect the SCS (P = 0.77), while the effects of age at first calving, lactation number, lactation stage, mean milk yield per milking day, and milk yield on the day of milk recording proved to be highly significant (P < 0.01). The present study was one of the first to show an association between polymorphism within the IL-17A gene and selected udder health traits in cattle. An influence of the c.126G > A polymorphism on clinical mastitis and the SCS in the studied set of Polish Holstein-Friesian cows was not found. This suggests that the c.126G > A marker is probably not relevant for genetic selection against mastitis in the analyzed breed.