Polymorphism in the promoter of TLR4 gene by PCR-RFLP and its association with somatic cell score in Chinese Holstein

Abstract. The objective of this study was to examine the effect of the polymorphism in the promoter of toll-like receptor 4 (TLR4) on mastitis and milk production traits. Two novel single nucleotide polymorphisms (SNPs) G-1539A before 5’-upstream region and G+265C in the 5’-UTR of TLR4 gene were detected, and genetic association analysis was applied on 421 Chinese Holstein cows. The statistical analysis indicated that two SNPs was significantly associated with 305 Days milk yield (P<0.05) and somatic cell score (SCS) respectively (P<0.01). Our results provide evidence that polymorphisms in the promoter of TLR4 are associated with milk production traits and SCS, and may be used as a possible candidate for marker-assisted selection and management in Holstein cattle breeding program.