Association Between Persistently Bovine Viral Diarrhea Virus-Infected Calves and Pen Levels of Morbidity and Mortality in an Iowa Feedlot

Abstract

As persistently infected (PI) cattle are the primary reservoirs of bovine viral diarrhea virus (BVDV) in cattle populations, there is general agreement that effective control of BVDV-induced losses requires the detection and elimination of these carriers from dairy and cowcalf herds. However, the significance of the presence of PI calves in pens of feedlot cattle is unknown. Our long-range goal is to determine whether identification and removal of PI calves prior to shipment to feedlots would be economically advantageous to feeders, and if such testing should be incorporated into preconditioning programs. As the first step toward answering this question, the objective of this study is to determine whether differences exist in morbidity and mortality in groups of calves that include PI calves and groups that do not include PI calves. If PI calves negatively impact morbidity and mortality, then future studies can be designed to examine the feasibility and economic impact of including BVDV PI testing in preconditioning programs.