Field Study

Exposure to Bovine Viral Diarrhea Virus Pre-weaning Mitigates the Effect of Constant BVDV PI Exposure During the Early Feeding Period

Abstract

Bovine viral diarrhea virus (BVDV) is a major pathogen involved in the bovine respiratory disease complex (BRD). Immunosuppression induced by BVDV is thought to contribute to BRD, exacerbating secondary bacterial and viral pneumonias. Calves persistently infected (PI) with BVDV maintain the virus in the cattle population and serve as the primary source of transmission within and between herds. The impact that PI calves have on overall feedlot calf health and performance has been shown to be significant. In this field study, calves from one farm, but from different BVDV exposure backgrounds, were monitored after entry into a feedlot in which constant exposure to BVDV virus occurred via presence of PI calves. The objective was to determine if different pre-weaning BVDV exposures mitigated adverse consequences of constant BVDV exposure in a feedlot setting.