During studies on bovine malignant catarrhal fever, 8 recently captured female wildebeest (Connochaetes taurinus) were injected daily for 1 week with the corticosteroid betamethasone. All developed pustular vulvovaginitis 7 to 9 days after the first injection. Infectious bovine rhinotracheitis virus (IBRV) was isolated from vaginal swabs from seven animals. Serum neutralizing antibody to IBRV was present in seven animals before injection of the corticosteroid, and the titres increased during convalescence. It is presumed that the wildebeest were latent carriers of IBRV in genital tissue. One of the IBRV isolates produced mild vulvovaginitis in a domestic heifer inoculated by the vaginal route.