Relationship between N-acetyl-beta-D-glucosaminidase activity and cell count, lactose, chloride, or lactoferrin in cow milk.

Activity of N-acetyl-beta-D-glucosaminidase was measured in foremilk samples collected from cows. A total of 64 samples were collected from these cows, some of which were affected by mastitis. They were examined for N-acetyl-beta-D-glucosaminidase activity, cell count in whole milk, and milk chloride, lactose, and lactoferrin. The correlation coefficient was .72 between activity and cell count, -.80 between activity and lactose, and .88 between activity and chloride. Therefore, the correlations between N-acetyl-beta-D-glucosaminidase activity and milk components, chloride and lactose, were larger than that between N-acetyl-beta-D-glucosaminidase activity and cell count. The correlation coefficient was high (.91) between N-acetyl-beta-D-glucosaminidase and lactoferrin. The N-acetyl-beta-D-glucosaminidase activity in cow's milk has potential for diagnosis of mastitis.