Abstract: The attenuated infectious bovine rhinotracheitis virus (IBRV) vaccine was tested for its safety and efficacy in host animals. In order to test the safety of the vaccine,one-month-old calves,6 to 8 month old calves,and heifers were inoculated with 2 mL (10 doses) of the vaccine. In the efficacy study,6 to 8 month old calves were vaccinated with single dose 1 mL of the vaccine. Then,the animals were challenged with a virulent challenge virus on 28 days post vaccination for immunogenicity of the vaccine. The results revealed that the calves of different ages did not show any clinical diseases post-vaccination. The new-born calves are normal and healthy,and no abortion,stillbirth or mummy fetus occurred in the pregnant cows. Immunogenicity study demonstrated that the vaccine provided five fifths protection to calves against the IBRV infection and clinical diseases caused by the challenge. The results indicated that the vaccine is safe and have a good efficacy to host animals.

Key words: infectious bovine rhinotracheitis virus (IBRV); attenuated vaccine; safety; efficacy