Risk factors for BRD on cow-calf operations

Abstract

Surveys of cow-calf producers indicate that bovine respiratory disease (BRD) in nursing (preweaned) beef calves is recognized on approximately 20% of operations. In the US BRD is reported to be the leading cause of death in preweaning calves 3 weeks of age and older. As compared to feedlot BRD or dairy calf BRD, relatively little information has historically been available regarding risk factors for the nursing calf BRD. Information regarding risk factors can support the development of management practices that prevent BRD by limiting exposure of calves to risk factors. Evidence available to date indicates that at the calf level, male calves, calves born with a twin, calves born to a heifer, and calves that experience dystocia requiring major assistance are at increased risk for preweaning BRD. At the herd level, nursing calf BRD risk is associated with factors that increase the opportunity for introduction of pathogens new to the herd, calf diarrhea, and events that provide opportunities for close contact among cows and calves. Because risk factors to date have been identified in cross-sectional surveys and thus are not necessarily causative, research is needed to determine whether modification of risk factors identified to date can decrease subsequent BRD on cow-calf operations.