EN
The activity of N-acetyl-β-D-glucosaminidase (NA-Gase) was determined in 40 samples of quarter milk from 40 healthy cows, and in 188 samples of secretion from subclinically and clinically inflamed udders, and in 181 sample of raw bulk milk collected from small private farms. The study was performed by ADC apparatuses and diagnostics delivered by ELKABE Ltd. The average activity of NAGase was the following: 125 AFU for health quarters, 220 AFU for the recovered quarters on the 21st day after treatment (s.c.c. 300 000), 260 AFU for the cases of latent udder infections caused by S. aureus or S. agalactiae (s.c.c. below 350 000/ml), 680 AFU for cases of subclinical bacterial or aseptic mastitis (average s.c.c. 3.5 milion/ml), and 1360 AFU for quarters affected with clinical forms of mastitis. The activity of NAGase in raw bulk milk was as follows: 117 AFU for s.c.c. below 200 000/ml, 123 AFU for s.c.c. 201 000-300 000/ml, 139 AFU s.c.c. 301 000-400 000/ml, 143 AFU for s.c.c. 401 000-500 000/ml, and 246 AFU for s.c.c. 0.75-1 mln/ml determined by Fossomatic. It has been noted that the state of healthy of udders and the changes in a quarter milk are determined more precisely by NAGase than by somatic cell count. The „cut off’ indicator and Applied Diagnostics Corporation computer programme are fully appropriate for the estimation of the hygienic acceptability of raw bulk milk.