American journal of veterinary research · 2014
Efficacy of a multivalent modified-live virus vaccine containing a Mannheimia haemolytica toxoid in calves challenge exposed with Bibersteinia trehalosi.
СтатьяРандомизированное исследованиеПоддержка исследования: вне правительства СШАНазвание и аннотация: Перевод пока не подготовлен
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Bowersock Terry L, Sobecki Brian E, Terrill Sarah J, Martinon Nathalie C, Meinert Todd R, Leyh Randy D
Аннотация
OBJECTIVE: To determine the efficacy of a multivalent modified-live virus (MLV) vaccine containing a Mannheimia haemolytica toxoid to reduce pneumonia and mortality rate when administered to calves challenge exposed with virulent Bibersteinia trehalosi. Animals-74 Holstein calves.
PROCEDURES: Calves were assigned to 2 treatment groups. Calves in the control group (n = 36) were vaccinated by SC administration of 2 mL of a commercial 5-way MLV vaccine, and calves in the other group (38) were vaccinated by SC administration of a 2-mL dose of a 5-way MLV vaccine containing M haemolytica toxoid (day 0). On day 21, calves were transtracheally administered B trehalosi. Serum was obtained for analysis of antibody titers against M haemolytica leukotoxin. Nasopharyngeal swab specimens were collected from calves 1 day before vaccination (day -1) and challenge exposure (day 20) and cultured to detect bacterial respiratory pathogens. Clinical scores, rectal temperature, and death attributable to the challenge-exposure organism were recorded for 6 days after challenge exposure. Remaining calves were euthanized at the end of the study. Necropsy was performed on all calves, and lung lesion scores were recorded.
RESULTS: Calves vaccinated with the MLV vaccine containing M haemolytica toxoid had significantly lower lung lesion scores, mortality rate, and clinical scores for respiratory disease, compared with results for control calves.
CONCLUSIONS AND CLINICAL RELEVANCE: Administration of a multivalent MLV vaccine containing M haemolytica toxoid protected calves against challenge exposure with virulent B trehalosi by reducing the mortality rate, lung lesion scores, and clinical scores for respiratory disease.
PROCEDURES: Calves were assigned to 2 treatment groups. Calves in the control group (n = 36) were vaccinated by SC administration of 2 mL of a commercial 5-way MLV vaccine, and calves in the other group (38) were vaccinated by SC administration of a 2-mL dose of a 5-way MLV vaccine containing M haemolytica toxoid (day 0). On day 21, calves were transtracheally administered B trehalosi. Serum was obtained for analysis of antibody titers against M haemolytica leukotoxin. Nasopharyngeal swab specimens were collected from calves 1 day before vaccination (day -1) and challenge exposure (day 20) and cultured to detect bacterial respiratory pathogens. Clinical scores, rectal temperature, and death attributable to the challenge-exposure organism were recorded for 6 days after challenge exposure. Remaining calves were euthanized at the end of the study. Necropsy was performed on all calves, and lung lesion scores were recorded.
RESULTS: Calves vaccinated with the MLV vaccine containing M haemolytica toxoid had significantly lower lung lesion scores, mortality rate, and clinical scores for respiratory disease, compared with results for control calves.
CONCLUSIONS AND CLINICAL RELEVANCE: Administration of a multivalent MLV vaccine containing M haemolytica toxoid protected calves against challenge exposure with virulent B trehalosi by reducing the mortality rate, lung lesion scores, and clinical scores for respiratory disease.