An inactivated combined vaccine of Infectious Bovine Rhinotracheitis (IBR), Bovine Viral Diarhoea (BVD), Parainfluenza-3 (PI-3) viruses and P. multocida and Phaemolytica using 0.2% formalin and alum gel as adjuvant. Fourteen susceptible calves were vaccinated twice 2 weeks apart using 5 ml I/M. The vaccine was tested for safety in calves and Guinea pigs and for the
sterility. Sera of immunized calves showed high antibody levels using serum neutralization test (SNT) which reached 4 for BR 8 for BVD and 8 for PI-3 after 5 week post vaccination. The ELISA was used to measure the level of antibodies which came in harmony with those of SNT. The average ELISA titre reached 4446 in IBR, 5984 in BVD and 4508 in PI-3 viruses, 3808 in P. mutocida and 3890 in P. haemolytica, a monovalent vaccine to each fraction in combined vaccine was used as a control. Passive mouse protection test was also used to evaluate the potency of pasteurella fractions in combined vaccine, where protection ranged from 60-100 for a period of 6 months post vaccination.