Vaccination against porcine reproductive and respiratory syndrome virus (PRRSV) reduces the magnitude and duration of viremia following challenge with a virulent heterologous field strain.

Forty PRRS-negative, three week-old weaned pigs were randomized into two groups in separate rooms and inoculated with a modified live PRRS vaccine (Fostera PRRS) or control (PBS). Four weeks after vaccination pigs were rehoused in a single room and challenged intranasally and intramuscularly with virulent PRRSV strain NADC20. Timed serum samples were collected and titrated for PRRS virus and anti-PRRS virus antibodies.

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.