title: Efficacy of a multivalent modified-live virus vaccine containing a Mannheimia haemolytica toxoid in calves challenge exposed with Bibersteinia trehalosi.
abstract: 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.
  
  
  METHODS
  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
  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.
authors: Global Biological Research, Zoetis Inc, Building 300 Dock, 333 Portage St, Kalamazoo, MI 49007.
authors: Terry L
authors: TL
authors: Bowersock
authors: Brian E
authors: BE
authors: Sobecki
authors: Sarah J
authors: SJ
authors: Terrill
authors: Nathalie C
authors: NC
authors: Martinon
authors: Todd R
authors: TR
authors: Meinert
authors: Randy D
authors: RD
authors: Leyh
mesh_terms: D000818:Animals; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000276:immunology*; D002417:Cattle; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D007279:Injections, Subcutaneous / Q000662:veterinary; D016018:Least-Squares Analysis; D008168:Lung / Q000473:pathology; D016978:Mannheimia haemolytica / Q000276:immunology*; D010326:Pasteurella Infections / Q000517:prevention & control / Q000662:veterinary*; D018410:Pneumonia, Bacterial / Q000517:prevention & control / Q000662:veterinary*; D014121:Toxoids / Q000008:administration & dosage / Q000276:immunology*; D014611:Vaccination / Q000379:methods / Q000662:veterinary*; D014613:Vaccines, Attenuated / Q000008:administration & dosage / Q000276:immunology
chemical_list: D001428:Bacterial Vaccines; D014121:Toxoids; D014613:Vaccines, Attenuated