Studies on induced Klebsiella mastitis with relationships among N-acetyl-beta-D-glucosaminidase, bacterial and somatic cell counts

Mastitis was induced by infusion of 3,000-7,000 colony-forming units of Klebsiella pneumoniae into the left rear quarter of four primiparous Holstein-Freisians. Greater than 100 organisms were recovered from a quarter milk sample within 2 hr and in 87.5% of the hourly cultures taken after 8 hr. Bacteria, California Mastitis Tests, somatic cell counts and N-acetyl-beta-D-glucosaminidase levels differed significantly from that of control quarters in infused cows after hr 6, 8, 9 and 9 respectively. High correlations were obtained between somatic cell count and N-acetyl-beta-D-glucosaminidase (r = .97) and N-acetyl-beta-D-glucosaminidase and natural log bacterial count (r. = .88). N-acetyl-beta-D-glucosaminidase was related to natural log bacterial counts of samples taken 1, 2, 3, and 4 hr prior to the test (rN-acetyl-beta-D-glucosaminidase and natural log bacterial count (r = .91, .92, .93, and .95).