Studies on the Diagnosis of Subclinical Mastitis in Cows by the Measurement of the Electrical Conductivity: 1. Comparison of Various Methods of Handling Conductivity Data with the Use of California Mastitis Test and Direct Somatic Cell Count

전기전도도(電氣傳導度) 측정(測定)에 의한 유우(乳牛) 준임상형(準臨床型) 유방염(乳房炎)의 진단(診斷)에 관한 연구(硏究) 1. 전기전도도법(電氣傳導度法)과 간접검진법(間接檢診法)(CMT 및 총체세포수(總體細胞數))과의 비교(比較)

A total of 466 foremilk from dairy farms in Chonnam district was examined for the subclinical mastitis over a period of one year, using a method of the electrical conductivities(EC); absolute conductivity(AC) and differential conductivity(DC) and quarter difference value(QD), in relation to the California mastitis test(CMT) and the direct somatic cell count(DSCC). The compatibility and efficiency rating between the EC values and the other screening tests was conducted. Obtained results are summarized as follows. 1. A linear relationship was found between the EC values and the CMT scores and direct somatic cell counts and it was found that electrical conductivity measurements were comparable with other screening tests for diagnosing animals with mastitis. 2. Compatibilities between the EC and CMT were 70.4% in AC, 74.6% in DC and 70.7% in QD, and that of the EC and DSCC were 53.0% in AC, 63.1% in DC and 53.2% in QD. On the other hand, relative efficiency ratings of Postle's equation between EC and CMT were 37.3% in AC, 26.5% in DC and 13.6% in QD, and that of the EC and DSCC were 33.1% in AC, 20.2% in DC and 11.9% in QD. 3. In the foremilk samples collected from damaged quarters determined by EC, the false positive rate wart higher than the false negative rate, and consequently tests of EC produced lower compatibility or efficiency rating scores. These tendencies suggested that any factors other than the mastitic condition influencing the EC values might be existed.