Use of a modified-live vaccine to prevent persistent testicular infection with bovine viral diarrhea virus.

*This study was supported by a grant from Pfizer Animal Health, Kalamazoo, Michigan. A commercial vaccine containing modified-live bovine viral diarrhea virus (BVDV; types 1 and 2) was administered to one group of 22 peripubertal bulls 28 days before intranasal inoculation with a type 1 strain of BVDV. A second group of 23 peripubertal bulls did not receive the modified-live BVDV vaccine before intranasal inoculation. Ten of 23 unvaccinated bulls—but none of the vaccinated bulls—developed a persistent testicular infection as determined by immunohistochemistry and polymerase chain reaction. Results of this study indicate that administration of a modified-live vaccine containing BVDV can prevent persistent testicular infection if peripubertal bulls are vaccinated before viral exposure. aDepartments of Pathobiology and Clinical Sciences College of Veterinary Medicine Auburn University Auburn, AL 36849