Importance of somatic cell count and california mastitis test in detecting subclinical mastitis in dairy cow

Forty six random samples of cow milk were collected from different localities at Sharkia Governorate, Egypt in a sterile bottle andtransferred to the laboratory in ice-box to maintain its chemical andmicrobiological status unchangeable. Each sample was mixedthoroughly before being divided into two parts.The first was examined for incidence of mastitis by applying CMT; WST; MSCCand chloride tests, the second was used for bacteriological examination(Isolation and identification of yersinia spp as well as Detection of thegene (virF) in Yersinia enterocolitica using PCR method).The results of CMT revealed that 13 (28.3%) of the examinedcow’s milk samples were negative and 33 (71.7%) were positive.While, results of WST showed that 12 (26.1 %) of examined cow milksamples were negative and 34 (73.9%) were positive samples.The MSCC/ml. was studied and reveals that negative samplescontained less than 3.55 x l 05 MSCC/ml., while the positive onescontained higher numbers of MSCC exceeded 6.8 x 106 /ml. There wasa marked increase in SCC in cow udder affected with subclinicalmastitis than that in normal milk.The mean value of chloride%/g of normal cow milk samples(CMT negative samples) was 0.105±0.027, while the CMT positivesamples were 0.168±0.002.The comparisons by 2-tailed test compare the mean values forMSCC/ml and chlorides% in normal and mastitis milk samplesshowed significant difference of mean at 0.01 levels.