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Bovine herpesvirus type 1 (BHV-1) is a major cause of reproductive failure. A study was conducted to determine if vaccination with a modified-live virus (MLV) vaccine containing BHV-1 at either 8 or 13 months prior to challenge protects against BHV-1 challenge-induced abortion. A total of 51 beef heifers, seronegative to bovine viral diarrhea virus types 1 and 2 and BHV-1, were vaccinated subcutaneously with a commercially available combination MLV vaccine containing BHV-1 and inactivated bacterin vaccine, or placebo containing bacterin only. The estrus cycle was synchronized and heifers were artificially inseminated approximately 6 or 1 month(s) after vaccination. Heifers were challenge-inoculated intravenously at approximately 193 days of gestation with a virulent BHV-1 virus. Clinical signs of BHV-1 infection were monitored for 14 days following challenge. Serological status and occurrence of abortion or stillbirth were also determined. Tissues collected from aborted fetuses (n = 22) and full-term calves that were born dead (i.e., stillbirth [n = 1] or dystocia [n = 2]) were tested for BHV-1 via virus isolation. BHV-1 was isolated from 1 fetus (7.7%) from Treatment Group 1 heifers (TGl - heifers challenged 13 months after BHV-1 MLV vaccination), from 3 fetuses/calves (15.8%) from Treatment Group 2 heifers (TG2 - heifers challenged 8 months after BHV-1 MLV v~ccination), and from 7 fetuses (36.8%) from Treatment Group 3 heifers (TG3 - control heifers that rec~ived bacterin only). Polymerase chain reaction testing results indicated that 1 fetus from the 13 (7. 7%) TG 1 heifers, 5 fetuses out of the 19 (26.3%) TG2 heifers, and 18 fetuses out of the 19 (94.7%) TG3 control heifers were BHV-1 positive. In this study, a combination MLV vaccine containing BHV-1 administered 8 or 13 months prior to challenge provided a significant level of protection against fetal infection in the face of a substantial challenge infection with BHV-1 when compared to nonvaccinated controls., The Bovine Practitioner, Vol. 47, No. 2 (2013 Summer)

A total of 22 commercial dairy calves were used to determine if vaccination of a modified-live bovine viral diarrhoea virus (BVDV) vaccine with adjuvants in the face of maternal antibody will protect calves from a virulent type 2 BVDV challenge within seven months post-vaccination, following the loss of maternal antibody. Neonatal calves were obtained prior to consuming colostrum and were randomly divided into three groups. Group 1 calves were fed an antibody-free colostrum supplement within six hours of birth. Calves in Group 2 and Group 3 were fed pooled colostrum obtained from cows vaccinated eight weeks prior to calving with a commercial inactivated combination vaccine containing BVDV1 and BVDV2. Group 2 calves were vaccinated at approximately 4.5 weeks of age with a commercial modified-live virus combination vaccine containing BVDV1 and BVDV2. Calves in Groups 1 and 3 were sham vaccinated. Seven months after vaccination, when calves in Group 3 became seronegative to BVDV2, calves in all three groups were challenged intranasally with virulent BVDV2, strain 1373. Calves that received colostrum and were vaccinated had only mild or no clinical diseases. Calves that did or did not receive colostrum and were sham vaccinated, developed severe diseases, with a 33-50% mortality rate. In this study, young calves vaccinated with a modified-live virus vaccine with adjuvants in the face of maternal antibody were protected against a virulent strain of BVDV., The Bovine Practitioner, Vol. 43, No. 1 (2009 Spring)