Bovine Viral Diarrhoea: Welfare Impact and Eradication

BVD is one of the most welfare-impactful cattle diseases — understanding persistently infected animals and eradication programs is essential for welfare-focused farmers.

Key Facts

• BVD virus creates persistently infected (PI) calves when it infects the fetus before 120 days of gestation
• PI animals are immunotolerant to the virus and shed it continuously throughout their lives
• PI calves may appear healthy or show failure to thrive, immune suppression, and early death
• Mucosal disease in PI animals causes severe, painful, untreatable enteritis and inevitable death
• National BVD eradication programs have eliminated the disease in Scotland and Scandinavia

Welfare Considerations

BVD causes welfare suffering across multiple mechanisms. Acutely infected cattle show fever, respiratory signs, and diarrhea. PI cattle face a more complex welfare picture: many appear normal initially but are immunosuppressed and susceptible to secondary infections throughout their lives. Those that develop mucosal disease face an untreatable, uniformly fatal condition with severe oral ulceration, haemorrhagic diarrhea, and rapid deterioration. The welfare imperative of BVD control is removal of PI animals from the herd — testing all calves and removing PI individuals eliminates the reservoir of infection and prevents the generation of new PI calves in pregnant cows. National eradication programs demonstrate that this is achievable at population scale.

What You Can Do

• Test all calves born in your herd for BVD persistent infection using ear notch or blood tests
• Remove PI animals from the herd humanely and promptly — they are the source of all BVD spread
• Vaccinate the herd to protect pregnant cows from fetal infection during PI animal removal
• Participate in your national or regional BVD eradication scheme
• Ensure any bought-in cattle have a clear BVD status before entering your herd