摘要 : 14 heifers, serologically negative to L. borgpetersenii serovar hardjo (LBH), were artificially inseminated and later challenged with a north-Queensland isolate of LBH by conjunctival inoculation. The heifers were serologically mo... 展开 14 heifers, serologically negative to L. borgpetersenii serovar hardjo (LBH), were artificially inseminated and later challenged with a north-Queensland isolate of LBH by conjunctival inoculation. The heifers were serologically monitored and their urine examined for the presence of leptospires using culture and fluorescent-antibody tests at appropriate intervals. Elective caesarean sections were performed on pregnant heifers at 6.5 weeks after the challenge. Fetuses were examined using serological,histopathological, microbiological and fluorescent-antibody tests. 10 of the heifers became pregnant, but 3 subsequently aborted before challenge. After challenge, all 14 heifers seroconverted and LBH was isolated from the urine of 6 of the 7 pregnant heifers. No evidence of fetal LBH infection was detected. Two of the fetuses had histopathological lesions consistent with Neospora sp infection. It is likely that the isolate of LBH used in the study does not normally infect the fetus. Neospora sp may bea more significant cause of bovine reproductive wastage. 收起