Review of health and performance effects of bovine viral diarrhea virus and testing for persistently infected feedlot cattle
Bovine viral diarrhea virus (BVDV) is an important pathogen commonly associated with bovine respiratory disease in feedlot cattle, and has varying effects on animal health and performance outcomes. The objective of this paper is to provide a review of the literature evaluating the effects of continued exposure to cattle persistently infected (PI) with BVDV, as well as testing and removing PI cattle from pen cohorts, on calf health and performance outcomes. Nine studies evaluated health and performance outcomes of cattle exposed to a PI-BVDV calf in their pen vs pens of cattle not exposed. Two additional studies evaluated the effects of testing and removal of PI animals from pens on health and performance outcomes compared to leaving a Pi-positive animal(s) in the pen with cohorts for varied periods of time. The literature evaluating the effects of testing and removing PI-BVDV calves from pen cohorts is limited, but does not suggest improvement in health and/or performance in calves by testing and removing PI-BVDV calves after arrival into the feedlot. Additional research is needed to evaluate the effect of testing and removing PI-BVDV calves prior to incorporating the practice in the field.