PREVALENCE OF HIGH SOMATIC-CELL COUNTS IN BULK TANK GOAT MILK

Higher SCC have been observed in goat milk than in cow milk. This study evaluated the prevalence of high SCC and determined whether increased neutrophils were a factor in high SCC. Bulk tank goat milk samples were collected from commercial dairy goat herds in California, Arkansas, Michigan, and Wisconsin. Total SCC were determined using a Fossomatic Electronic Cell Counter and microscopically using pyronin Y-methyl green stain. Differential counts were determined using Wright's-stained cytospin centrifuge preparations. Average SCC were high (6.12 log10 cells/ml; geometric mean, 1.32 x 10(6) cells/ml). The average of the Fossomatic and direct microscopic SCC indicated that 8.6% of the producers had SCC <.75 x 10(6) cells/ml and that 34.5% were <1 x 10(6) cells/ml. The current goat milk SCC standard is 1 x 10(6) cells/ml; the cow milk SCC standard will be .75 x 10(6) cells/ml in 1993. Milk samples contained 9.9% macrophages, 2.8% lymphocytes, and 87% neutrophils. These data indicate that high SCC were prevalent and that increased neutrophils contributed to high SCC in the bulk tank goat milk.