A Study on the Somatic Cells in Quarter Milk Samples of Holstein Cows with Suspected Mastitis

유방염으로 의심된 유우 분방유즙의 체세포 연구

This study was conducted to survey the relationship between the somatic cell count (SCC), and California mastitis test (CMT) & mastitis. A total of 328 quarter milk samples were collected from 211 cows suspected to have mastitis; Both SCC and CMT were performed on the samples. Milk smear was stained with Broadhurst and Paley stain and the cells were classified into either epithelial or blood cells. Bacterial isolation was made and antimicrobial susceptibility was tested. Of the 328 quarters, 78 ($23.8{\%}$) were CMT negative with SCC <750,000/ml. As expected, CMT score increased with the increase of SCC. The number of epithelial cells decreased with the increasing number of somatic cells, while the opposite was the case with the number of blood cells. The critical point was when the SCC reached 1,000,000/ml. Up to 1,000,000 cells/ml, the number of epithelial cells was greater than that of blood cells. The results indicate that when epithelia:blood cell ratio is 58.1:41.9, the milking line should be checked and bacterial isolation be performed on the samples in order to identity mastitis.