TLR4 is a highly polymorphic gene and related with mastitis, therefore the present study was carried out on 190 lactating Sahiwal cattle, maintained at NDRI, Karnal to explore polymorphism in TLR4 gene and to study its association with mastitis in Sahiwal cattle. Polymorphism in exon 3 region of TLR4 gene detected by PCR-RFLP using HinfI restriction enzyme and Six SNPs were identified, out of which one non synonymous SNP result into change of amino acid (Valine to Isoleucine). 1336447186.php