Polymorphism in the promoter of &amp;lt;i&amp;gt;TLR4&amp;lt;/i&amp;gt;
gene by PCR-RFLP and its association with
somatic cell score in Chinese Holstein

Huilin Zhang,Hongliang Wang,Zhixiong Li,Lijun Wang,Caixia Ru,Xiaolin Liu,Ailong Song,Ling Chen

doi:10.7482/0003-9438-57-006

Abstract

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.

Highlights

Bovine mastitis, defined as »an inflammation of the mammary gland«, is generally considered the most frequent and costly disease of dairy cattle
According to the sequence mutations, the polymerase chain reaction (PCR) products could be digested with BglI and MspI restriction enzymes
This study suggests significant association of the promoter of toll-like receptor 4 (TLR4) gene genetic variation in determining bovine’s somatic cell score (SCS) and milk production traits

Summary

Introduction

Bovine mastitis, defined as »an inflammation of the mammary gland«, is generally considered the most frequent and costly disease of dairy cattle. Financial losses due to mastitis occur for animals experiencing both subclinical and clinical disease. Losses resulting from clinical mastitis are usually apparent and consist of discarded milk and transient reductions in milk yield (Ruegg 2003). Additional losses include the risk of antibiotic residues and culling or death of affected animals (Ruegg 2003). The disease cost to the dairy industry was 1.5 billion € annually in the Europe (Seegers et al 2003). This is due to increased involuntary culling, therapeutic costs, reduced milk yield and changes in milk composition

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