Evaluation of the efficacy of a modified-live combination vaccine against abortion caused by virulent bovine herpesvirus type 1 in a one-year duration-of-immunity study.

This study demonstrated that a multivalent vaccine containing modified-live bovine herpesvirus type 1 (BHV-1) protected pregnant heifers and their fetuses against virulent BHV-1 challenge exposure at 365 days after vaccination. The percentage of abortions or fetal deaths caused by BHV-1 was significantly higher in control heifers (10 of 10 [100.0%]) than BHV-1–vaccinated heifers (three of 19 [15.8%]). Evaluation of the Efficacy of a Modified-Live Combination Vaccine against Abortion Caused by Virulent Bovine Herpesvirus Type 1 in a One-Year Duration-of-Immunity Study*