[Effectiveness evaluation of inactivated vaccines against bovine viral diarrhea and infectious bovine rhinotracheitis]

ABSTRACT

Bovine viral diarrhea [BVD] and infectious bovine rhinotracheitis [IBR] are two of the most important diseases responsible for major economic losses in the Iranian dairy industry. Since there are not in-house vaccines, the evaluations of the effectiveness of imported commercial vaccines are imperative. The purpose of the present study was to assess the clinical effectiveness of commercial inactivated Bovine viral diarrhea virus [BVDV] and Bovine herpes virus type 1 [BHV-1] vaccines to reduce the occurrence of culling and diseases, as well as their impact on milk production and prevention of birth of calves persistently infected [PI] with BVDV. A blind randomized controlled trial was performed. Animals were assigned to treatment [n=342] and control [n=351] groups by systematic randomization. Animals in the treatment group were inoculated with inactivated BVDV and BHV-1 vaccines [Intervet-Schering Plough]. One and seven months later, vaccination was repeated. Over a one-year period, the incidence of disease, death and culling, birth of PI calves and milk production were recorded and compared. All statistical analyses were done with IBM SPSS statistics 20 software. At the start of the study, the two groups showed no significant differences in the means of age [day], parities, days in milk, milk production and preexisting antibodies of BVDV and BHV-1. In addition, significant difference was not observed between treatment and control groups during the period of study. Unlike previous years, there were no reports of BHV-1 respiratory disease and birth of PI calves in the herd as a whole. Although the efficacies of the mentioned vaccines were approved previously, effectiveness was not augmented in our study. Evidence-based Vaccinology in the developing countries should be performed by implementation of effectiveness studies