Researches On Investigation And Monitoring Technique Of Subclinieal Mastitis Of Dlairy Cows In Dail Region

To determine the simplest, most convenient, easiest operating, suitable for field examine method to diagnose the sub-clinical mastitis, during July, 2004 to November, 2004, 106 dairy cows had been randomly selected from 10 natural villages of Eryuan county and Dali which was the major milk-produing areas in Dali autonomous prefecture, all these dairy cows were healthy and no abnormal change in the milk observed by eyes, the methods SCC (somatic cell count, Little and Plastrige), C·M·T (California mastitis test) and B·T·B(bromine thymol blueness) had been compared. The incidence of sub-clinical mastitis and its epidemiologic regularity were analyzed by using these methods. At the same time, The 12 milk specimens, which showed ++ and +++ tested by the measurement of CMT, had been took to laboratory to isolate and identify the pathogen. The results indicate:1. The positive rate of subclinical mastitis of cows in Dali region was 44.00%-61.73%, average rate was 57.55%;the positive rate of milk area was 23.58%-32.08%, average ratio was 29.24%.The incidence of subclinical mastitis of cow was lower in Hui Clan of Dali region than Han Clan of Eryuan county ,and the difference was significant.(p<0.05).2. The incidence of subclinical mastitis of cow have some relationship with the ages, parity and the milk areas of mammary gland in Dali, but it has no significant difference(p<0.05).3. The incidence of subclinical mastitis in Dali has close relationship with milk yield and season, and the difference was significant.(p<0.05);4. There was greatly significant difference (p<0.01) between the incidence of subclinical mastitis and the number of infected milk area of mammary gland in Dali, the incidence of subclinical mastitis was negatively correlated with the number of infected milk region of mammary gland (p<0.05), but usually infected milk region was only one. The different number of milk area with positive results of +, ++ and +++ by the method of CMT had great significant difference (p<0.01); The incidence of milk area of mammary gland was ranked from + to +++ by reactive intensity.5. Through isolating and identifying pathogenic bacteria from the 12 milk samples with the results of ++ and +++ by method of CMT, we found 9 kinds of bacteria and 455 strains of bacteria in all. Among those 7 kinds of bacteria and 323 strains of bacteria have close relationships with mastitis. The positive rates of all kinds of strains of bacteria were as follows: staphylococoal aureus 37.33% (122/323), escherichia coli 25.08%(81/323), proteus 9.60% (31/323), streptococcus dysgalactiae 9.29%(30/323), streptococcus agalactiae 7.74% (25/323), klebsiella 7.74% (25/323), streptococcus uberis 3.09% (10/323).6. Through isolating and identifying the bacteria from the 12 milk samples, we found contagious pathogen in 5 milk samples, and the positive rate of contagious pathogen 41.67%, environmental pathogen in 4 milk samples, the positive rate 33.37%, and both environmental pathogen and contagious pathogen in 3 milk samples, the positive rate 25.00%, and we found 3 cases infected with 1 pathogen, 7 cases with 2 pathogens, 2 cases with 3 pathogens in the whole 12 milk samples .7. Through comparatively examining on the milk samples of dairy cow in Dali by the methods of Little, Plastrige, CMT, BTB, We considered CMT was a simple, convenient, easily operating, exact method, and it can be widely extended and utilized into production.