| In order to provide theoretical foundation for controlling SCC in raw milk, the correlation among SCC, indigenous enzymes and bovine milk stability were studied. The milk SCC, plasmin, NAGase, peroxidase, catalase, lipase , FFA, FAN, alcohol stability and heat coagulation time of 982 milk samples from 7 meadows were analyzed and compared for different SCC(<200,000cells/mL, 200,000-500,000cells/mL, 500,000-1,000,000cells/mL, >1,000,000cells/mL). The results showed:1. The mean SCC of 982 milk samples was 870,200 cells/mL and the stdev was 1,468,900 cells/mL. The milk SCC did not fit the normal distribution.2. The levels of plasmin, NAGase, peroxidase, catalase, lipase, FFA and FAN increased with SCC (P<0.001); when SCC was increased, heat coagulation time decreased (P<0.001).3. Positive correlation coefficient (P<0.001) was found during SCC, other indigenous enzymes, FFA and FAN. Heat coagulation time was much significantly negatively related with SCC (P<0.001).4. Plasmin correlated to FAN (p<0.001), R is 0.3628; FFA correlated to lipase (p<0.001), R is 0.5396; heat coagulation time correlated to free calcium (p<0.05), R is 0.1280; heat coagulation time correlated to urea content (p<0.001), R is 0.3897; heat coagulation time correlated to whey protein (p<0.01), R is-0.4180; heat coagulation time had no relationship with pH.5. Under the same quality of management, the milk alcohol stability decreased along with SCC increased; when pasture management levels were different, the milk alcohol stability assumes the disorder changes along with SCC increased.6. The meadows that had a low bulk milk SCC (910,000 cells/mL) had better management than those meadows that had a high bulk milk SCC (1,480,000 cells/mL).There is significant difference between the two management practices (p<0.05).7. The SCC in September were higher than these in others in Huhhot, so we must adopte more measures to prevent mastitis. |
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