The role of coagulase-negative Staphylococcus spp. and associated somatic cell counts in the ovine mammary gland.

The somatic cell count (SCC) of ewes' milk was determined by the Fossomatic method and compared with the bacteriological status of the mammary gland. Of 366 samples from uninfected udder halves, 64.5% had SCC less than 50 x 10(3) cells/ml, 81.9% had SCC less than 250 x 10(3), and 92.4% had less than 500 x 10(3) cells/ml. Of 130 bacteriologically positive samples, 91.1% had SCC more than 500 x 10(3) cells/ml and 98.8% more than 250 x 10(3). Of the examined milk samples 26.2% showed positive bacteriology during the single sampling. The most frequent pathogens isolated from the milk samples were coagulase-negative staphylococci. Considering our results, 250 x 10(3) cells/ml should be the threshold value, which could be regarded as the upper limit for normal SCC of ewes' milk.