Cathelicidin Responded to Streptococcus agalactiae and Associated with the Severity of Subclinical Mastitis

Abstract

Cathelicidin in milk was reported as a possible protein marker for the assessment of the severity of subclinical mastitis. We hypothesized that cathelicidin would be elevated in the mastitic milk of the Streptococcus agalactiae-subclinical mastitis and the elevation of cathelicidin may be related to somatic cell count (SCC). Western blot was used to determine the amount of cathelicidin to differentiate between normal milk and S. agalactiae subclinical mastitic milk. The correlation between amount of cathelicidin and the SCC was also determined. We found that S. agalactiae subclinical mastitis induced cathelicidin expression in milk. There was a significant correlation between the amount of cathelicidin and the SCC (n=56, r= 0.411). Our findings confirmed cathelicidin as a promising biomarker for subclinical mastitis and indicator of the severity of mammary infection.