Analysis of genetic polymorphism of IL8R receptor gene a marker associated with bovine mastitis among crossbred cattle

Abstract

A total of 60 crossbred cattle were screened for subclinical and clinical mastitis in and around Jabalpur using California mastitis test (CMT) followed by somatic cell count (SCC). The DNA was isolated and 311 bp fragments of IL8R gene was amplified using PCR. PCR-SSCP (Single Strand conformational polymorphism) method was used to identify genetic polymorphism of 311 bp amplicon of IL8R gene. PCR-SSCP revealed five SSCP patterns, SSCP pattern 1 (P1) was present in highest percentage 63.6% in healthy group, SSCP pattern 3 (P3) was present in highest percentage 64.2% in subclinical mastitis group while SSCP patterns (P2 and P5) were present in highest frequency 100% and 100% respectively in clinical mastitis group. Cattles exhibiting pattern P2, P5 and P3 were significantly (p<0.05) associated with susceptibility to clinical and subclinical mastitis in crossbred cattle while those exhibiting pattern P1 were significantly (p<0.05) associated with mastitis resistance. The animals exhibiting SSCP pattern P1 may have IL-8R haplotypes that are good genetic markers for increased mastitis resistance while animals exhibiting pattern P2, P5 and P3 may have IL-8R haplotypes as good genetic markers for clinical and subclinical mastitis susceptibility. Thus, animals exhibiting these patterns can be selected or culled at an early age for future breeding.