Bovine viral diarrhoea (BVD) is a highly significant cattle disease that reduces welfare through immunosuppression, reproductive failure, and neonatal mortality, but can be eradicated through systematic testing and biosecurity programs.
BVD creates diffuse, widespread welfare harm across affected herds. PI animals themselves may appear clinically normal but shed enormous quantities of virus — their welfare is compromised by lifelong immunosuppression that makes them susceptible to secondary diseases. In herds with active BVD circulation, calves suffer from pneumonia, scour, and failure to thrive at rates far above BVD-free herds — the immunosuppressive effect of BVD compounds every other disease challenge. Reproductive losses — abortions, foetal abnormalities, and weak calves — affect ewes and cows silently across entire production years. The Scottish eradication model demonstrates that national freedom is achievable: systematic PI identification and removal, strict biosecurity for cattle movements, and vaccination to protect susceptible animals achieved freedom in under a decade. Countries that implement similar programs see dramatic reductions in pneumonia rates, calf mortality, and antibiotic use — BVD eradication is one of the highest-welfare-impact interventions available in cattle farming.