PHYSIOLOGICAL THRESHOLD OF SOMATIC-CELL COUNT AND CALIFORNIA MASTITISTEST FOR DIAGNOSIS OF CAPRINE SUBCLINICAL MASTITIS

Three hundred and sixty-nine milk samples from half udders of 188 Murc iano-Granadina goats in the second and third month of lactation, from ten commercial dairy goat herds were studied, Bacteriological analyses , California Mastitis Test (CMT) and somatic cell count (SCC) by Fosso matic Counter were performed, The best SCC threshold for defining subc linical mastitis was 500 x 10(3) cells ml(-1), but this threshold had a poor positive predictive value (28.5%) and only 62.3% of samples wer e correctly classified. Arithmetical and geometrical means of SCC show ed statistical differences between infected and uninfected glands, Ari thmetical and geometrical means of SCC per microlitre for each CMT sco re were, respectively: 312 x 10(3) and 172 x 10(3) for Score 0 and tra ces; 1014 x 10(3) and 531 x 10(3) for Score 1; 2912 x 10(3) and 2051 x 10(3) for Score 2; and 4950 x 10(3) and 4436 x 10(3) for Score 3. The CMT Scores 2 and 3 discriminated between infected and uninfected udde r glands. The results show that both tests could be used in the period of study to detect a high percentage of true uninfected glands but th e percentage of false positives was high.