Serum and Colostral Antibody Levels in Cattle Convalescent from Foot-and-Mouth Disease: Tests in Calves and Fetal Tissue

[摘要] Two heifers were inoculated with foot-and-mouth disease virus (FMDV) in late pregnancy. Twelve days after inoculation, one heifer calved. Both the heifer and calf died 3 days after parturition. The other heifer calved 18 days after inoculation, but the calf was stillborn. The dam was sacrificed at 12 days postpartum. Antibody levels were determined in sera and milk and attempts were made to isolate the virus from fetal membranes and calf tissue with the following results: 1. 1. Postpartum milk from a heifer infected with foot-and-mouth disease (FMD) contained specific neutralizing antibody at a level higher than that of serum from the same animal at 7 days postinoculation (DPI); at 5 days postpartum the titers of serum and colostrum were comparable.2. 2. Complement-fixation (CF) titers of postpartum whey were lower than the serum titers and were not detectable after 10 days.3. 3. An extremely high concentration of whey proteins with globulin mobilities, as shown by paper electrophoresis, was noted during the first 5 days postpartum; however, the concentration of these proteins gradually decreased to an insignificant level by the 10th day.4. 4. Foot-and-mouth disease virus (FMDV) was not recovered from meconium, spleen, pancreas, heart muscle or placental tissues of the calves.5. 5. The symptoms in pregnant heifers following infection with FMDV, type A-119, were more severe than those noted in steers or nonpregnant heifers.6. 6. The virus neutralization (VN) test was more useful than the agar gel precipitin or CF test because of the persistence of VN antibody in milk.

[学科分类] 生物科学（综合）