Microflora and somatic cell content of goat milk

The results of tests to determine the microflora and somatic cell content of 483 milk samples from 250 dairy goats in the North of Scotland are presented. Milk from uninfected udders had extremely low levels of bacterial contamination, 80 per cent of such samples having less than 100 bacteria/ml. One quarter of all samples were infected, the organisms isolated being coagulase negative staphylococci (83.5 per cent), coagulase positive staphylococci (12.4 per cent) streptococci (3.3 per cent) and Escherichia coli (0.8 per cent). Streptococcus agalactiae was not detected. Somatic cell count levels were higher than those usually found in cows' milk: 33 per cent more than 2,000,000/ml; 22 per cent between 1,000,000 and 2,000,000/ml; 25 per cent between 500,000 and 1,000,000/ml; 22 per cent less than 500,000/ml. The levels of cell counts were similar for uninfected halves and halves infected with coagulase negative staphylococci. Halves infected with coagulase positive staphylococci had much higher cell counts, eg, 73 per cent in excess of 2,000,000/ml. The interpretation of tests based on somatic cell content as indicators of mastitis in goats is discussed.