EVALUATION OF INACTIVATED INFECTIOUS BOVINE RHINOTRACHEITIS (IBR) AND PARAINFLUENZA-3 (PI-3) VACCINE IN SHEEP

The locally prepared inactivated respiratory virus vaccine (Pneu‌mo-3) which contains IBR, PI-3 and BVD viruses was used to immunize 18 lambs free of IBR and PI-3 virus antibodies. These were divided into 2 groups, the first was immunized with 2 doses of the vaccine 2 weeks apart, and the second was kept as control. Kinetics of immune response were elicited by ELISA and SNT against IBR and PI-3 constituent of the vaccine and I-11 against PI-3 virus only. The protective capacity of each constituent was studied by chal-lenge exposure which was performed on one month post vaccination (PV). The unvaccinated control lambs became affected by each chal‌lenge dose, they were shedding the virus and showed clinical symptoms post-infection. The immunized lambs and contact control lambs did not exhibit clinical symptoms and did not shed the viruses. Adverse reactions were not observed in lambs following vaccination. The results indicated that vaccination with Pneumo-3 can provide protection against IBR and PI-3 virus infection in sheep.