| Summary |
In Peng-Fu field test, 7,942 pigs were vaccinaal with BVD vaccine and 5,269 pigs with Lit vaccine at 3 weeks of age from April to Dften*er of 1976. Neither clinical signs nor hog cholera case was found during the field trial. Ten months aft the first vaccination in the field trial, 696 sera were collect! at slaughter house monthly from BVD vaccinat! pigs during the pericd of Febuary and July of 1977. The distribution of BVD antibody among 696 sea varied gxeatly; 244 sea showal no antibody titer, whilelloseadatiterhigherthanx2S6.Mostofsea(91,24%)hadnohogcholea Summary antibody, but 61 sea (8.76%) showed low antibody response against HCV., Thirteen out of 32 BVD antigen vaccinated pigs at 10 or 17 weeks old survived after challenge with virulent HCV. All survived pigs had vixemia, leucoienia and virus shedding in urine and feces during fever response, The level of BVD antibody titers in the pigs showed no important relationship with their resistance to HCV challenge. However, the prcduction of antibody against both BVD and HC virus in survived pigs had an anamnestic response aft challenge with HCV. There was no significant difference in BVD antibody distribution in Peng-Fu yellow cattle bufore and po€t field test
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