Studies On Pathogenicity And Immunogenicity Of Main Pathogenic Bacteria Causing Mastitis In Dairy Cows

Dairy cow mastitis is a common and frequent disease, and it may cause great economic loss in the dairy industry.The study of Pathogenicity and Immunogenicity will lay a foundation for mastitis controlling.The study of the propolis immunogen preparations can provide evidence for development of dairy cow mastitis vaccine, and provide reference for other propolis vaccine studing.In these experiments the pathogenicity and immunogenicity of pathogenic bacterium to mouse were studied. In the pathogenicity test, the pathogenic bacterium was used to inject into the peritoneal cavity of mouse. Their clinical symptoms and pathological changes after infection were recorded.By artificial infection test, we have proved the pathogenicity of the bacterium. Animal pathogenicity test sh-owed that it could cause mouse to mobidity.It is great significance for the selecti-on of laboratory animals,which can laid theory basis for studying bovine mastitis.In the immunogenicity test,the propolis immunogen preparations has been made.Its physical properties and chemical properties were test according to the conventional vaccine test regulation.The results showed that the antigen preparations were complied with the conventional vaccine test order and the antigen preparations does have of good safety.In the animal protective immunity test, the antigen preparation was used to inject into the peritoneal cavity of mouse in order to induce preliminary immunoresponse, and later a challenge infection was made in immunized mouse by pathogenic bacterium into the peritoneal cavity for testing the protective immunity. The results showed that in case of Staphylococcus aureus the protection index (PI) were 37.15,30and 26.5.While in cases of Streptococcus and Escherichia coli the protection index (PI) were 50 and 10.The results showed that the antigen preparation has some protective immunity compared with control group. The results of pathological check showed that pathological changes in experiment group were slighter than control group.The analysis of immune cells in different tissues and organs of mouse indicated that the antigen preparations dose have of some immunogenicity. The results laid basis for preventing and curing bovine mastitis in clinical application.