OBJECTIVE: To protect neonatal calves against fatal salmonellosis within the first 2 weeks after birth, using chicken egg yolk antibodies specific against Salmonella typhimurium or S dublin. ANIMALS: 38 neonatal Holstein calves from Salmonella-free farms. PROCEDURE: After removal of the lipid components with hydroxypropylmethylcellulose phthalate, egg yolk antibodies were spray dried. At 4 days of age, calves were challenge exposed by oral inoculation with 10(11) virulent S typhimurium (experiment 1) or S dublin (experiment 2). Starting from the challenge-exposure day, egg yolk antibody preparations were administered orally 3 times a day for 7 to 10 days. RESULTS: In passive immunization trials, the orally administered antibodies conferred dose-dependent protection against infection with each of the homologous strains of Salmonella. Within 7 to 10 days after challenge exposure, all control calves died, whereas low-titer antibody-treated calves had 60 to 100% mortality. Only fever and diarrhea, but no deaths (P < 0.01), were observed in calves given the highest titer of antibody. CONCLUSIONS AND CLINICAL RELEVANCE: Compared with that in control calves, survival was significantly higher among calves given antibodies with titers of 500 (P < 0.05) and 1,000 (P < 0.01) homotypic for S typhimurium and with titer of 5,000 (P < 0.01) for S dublin. Egg yolk antibodies specific for whole cell S typhimurium or S dublin are protective against fatal salmonellosis when given in sufficiently high concentration, and may be clinically useful during a salmonellosis outbreak.
OBJECTIVE: To protect neonatal calves against fatal salmonellosis within the first 2 weeks after birth, using chicken egg yolk antibodies specific against Salmonella typhimurium or S dublin. ANIMALS: 38 neonatal Holstein calves from Salmonella-free farms. PROCEDURE: After removal of the lipid components with hydroxypropylmethylcellulose phthalate, egg yolk antibodies were spray dried. At 4 days of age, calves were challenge exposed by oral inoculation with 10(11) virulent S typhimurium (experiment 1) or S dublin (experiment 2). Starting from the challenge-exposure day, egg yolk antibody preparations were administered orally 3 times a day for 7 to 10 days. RESULTS: In passive immunization trials, the orally administered antibodies conferred dose-dependent protection against infection with each of the homologous strains of Salmonella. Within 7 to 10 days after challenge exposure, all control calves died, whereas low-titer antibody-treated calves had 60 to 100% mortality. Only fever and diarrhea, but no deaths (P < 0.01), were observed in calves given the highest titer of antibody. CONCLUSIONS AND CLINICAL RELEVANCE: Compared with that in control calves, survival was significantly higher among calves given antibodies with titers of 500 (P < 0.05) and 1,000 (P < 0.01) homotypic for S typhimurium and with titer of 5,000 (P < 0.01) for S dublin. Egg yolk antibodies specific for whole cell S typhimurium or S dublin are protective against fatal salmonellosis when given in sufficiently high concentration, and may be clinically useful during a salmonellosis outbreak.