Investigation of the Role of Bovine Viral Diarrhea Virus in Undifferentiated Fever of Feedlot Cattle

Abstract

The undifferentiated fever (UF)/bovine respiratory disease (BRD) complex continues to be the single most important infectious disease entity in beef feedlot production. Current management practices have focused on successfully managing this disease complex through the use of prophylactic and therapeutic antimicrobial strategies. However, there are substantial amounts of concrete and circumstantial epidemiologic, pathologic, serologic and immunologic evidence of an association between bovine viral diarrhea virus (BVDV) and the UF/ BRD complex. Unfortunately, there are limited data that describe how the transmission of BVDV in the feedlot occurs and how this transmission leads to the development of UF/BRD. The purpose of the proposed project is to improve our understanding of the role that BVDV plays in the pathogenesis of pen-level UF/BRD, through the development/refinement of diagnostic tests for identifying and differentiating animals with BVDV, so that appropriate management intervention strategies can be developed to reduce BVDV transmission/infection in commercial feedlot production. In the first phase of the study, population-based, morbidity-based and mortality-based BVDV testing surveys will be conducted in a population of 40 pens (approximately 12,000 animals) of auction-market derived feedlot calves, housed in four commercial feedlots. The results of the BVDV testing surveys, in conjunction with the individual-animal based computerized health records collected at the feedlot, will be used to describe BVDV transmission/infection in pens of commercial feedlot animals.