The influence of TLR4 gene polymorphisms on milk quality and composition of Lithuanian Holstein cows

Abstract

This study investigated bovine TRL4 gene c.9421C>T, c.2021C>T and c.-10C>T polymorphisms and their relationship with somatic cell count and indicators of milk composition. Blood samples were collected from 152 Lithuanian Holstein dairy cows. The method of polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) was used to genotype TLR4 gene polymorphisms. The data concerning somatic cell count and milk composition indicators (fat, protein, lactose) were analysed. The influence of genes and statistical significance of differences between different genotypes was evaluated by the one-factor dispersion analysis (ANOVA). Results showed that c.9421C>T was significantly associated with somatic cell count in milk. Also a significant association between the genotypes of c.9421C>T and somatic cell count was found (P<0.05). Cattle with the TT genotype showed the lowest somatic cell count. TLR4 gene polymorphisms c.2021C>T and c.-10C>T have no significant effect on mastitis resistance and milk composition. Analysis of the combined genotypes TC/CC of c.2021C>T and c.9421C>T allowed us to determine the possible association of SNPs with the somatic cell count and lactose content. The study showed a significant association between the somatic cell count (SCC) and TLR4 polymorphism c.9421C>T in Lithuanian Holstein cows. SCS of cows with a TT genotype was significantly lower and indicated the association of TT genotype with resistance to mastitis in c.9421C>T and allele T might be the beneficial allele for mastitis resistance.