EVALUATION OF GENES ASSOCIATED WITH MASTITIS IN CROSSBRED DAIRYCATTLE

Mastitis affects dairy production economically. It also associated with increased somatic cells in milk, these cells include; neutrophils, macrophages, lymphocytes, and mammary epithelial cells. They are used as an indicator to monitor udder health status of dairy cattle. Somatic cell count has higher heritability as compared to mastitis, thus it can be used as a trait for selection of mastitis resistance. The objective of this study was to evaluate genes associated with mastitis in crossbred dairy cattle. Blood samples were collected from 96 crossbred cattle for DNA analysis, and a total of 152 milk samples were collected from full udder quarters of 38 lactating crossbred dairy cattle for SCC analysis. Genomic DNA of beta-lactoglobulin and lactoferrin genes were amplified using two pairs of oligo primers 252 bp and 301 bp respectively. Their amplified products yielded 27 fragments at the 301-bp and 23 fragments at 252-bp. Results of PCR-DNA sequencing found out that there were several genetic variations in sequences, which were identified as Single Nucleotide Polymorphism (SNPs) associated with mastitis susceptibility. This study strongly suggests that beta-lactoglobulin and lactoferrin are novel candidate genes for selection of mastitis resistance in crossbred dairy cattle.