Comparison of three commercial vaccines for preventing persistent infection with bovine viral diarrhea virus

Eighty crossbred beef heifers were randomly allocated to four groups to evaluate the efficacy of vaccination in preventing development of calves persistently infected with bovine viral diarrhea virus (BVDV) Group 1 (n = 11) was non-vaccinated controls, whereas three groups were vaccinated with commercially available multivalent BVDV vaccines at weaning (similar to 7 mo of age), 28 d post-weaning, similar to 1 y of age. and 28 d later Groups 2 (n = 23) and 3 (n = 23) were given a modified-live BVDV vaccine, whereas Group 4 was given an inactivated BVDV vaccine Heifers were bred by Al and subsequently exposed to two bulls At 61 d after Al, 70 heifers were pregnant (n = 10 for Group 1 and n = 20/group for Groups 2, 3, and 4) Three cattle persistently infected with BVDV were commingled with the pregnant heifers (in an isolated pasture) from 68 to 126 d utter Al Thereafter, viremias were detected in pregnant heifers from Groups 1, 3, and 4 (10/10, 1/20, and 10/20, respectively), but not in pregnant heifers from Group 2 (0/20). Resulting calves were assessed for persistent infection using serum PCR, ear notch antigen capture-ELISA, and immunohistochemistry. Persistently infected calves were only produced in Group 1 (10/10) and Group 4 (2/18) In conclusion. commercial vaccines provided effective fetal protection despite prolonged natural exposure to B V DV Given that viremias were detected in 11 vaccinated heifers after BVDV exposure, and two vaccinated heifers gave birth to persistently infected calves, there is continued need for biosecurity and diagnostic surveillance. in addition to vaccination, to ensure effective BVDV control (C) 2010 Elsevier Inc All rights reserved