Efficacy of a multivalent modified-live virus vaccine containing a Mannheimia haemolytica toxoid in calves challenge exposed with Bibersteinia trehalosi.

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.