Bovine Respiratory Syncytial Virus and Calf Welfare

Bovine respiratory syncytial virus (BRSV) is a major cause of severe respiratory disease in young calves, causing significant welfare problems in autumn and winter.

Key Facts

BRSV causes severe lower respiratory tract disease in calves under 6 months, often presenting as acute dyspnoea and hypoxia
Outbreaks are most common in housed autumn-born calves; mixing at housing increases exposure and disease severity
Untreated BRSV pneumonia has high mortality; even treated cases may have lasting lung damage affecting long-term welfare
Vaccination programmes have been shown to reduce BRSV incidence and severity in at-risk calf groups

Welfare Considerations

BRSV causes acute severe respiratory distress — a high-priority welfare problem. Affected calves breathe with obvious effort, show open-mouth breathing, have elevated temperatures and are profoundly weak. The acute phase lasts 3-5 days, with welfare during this period critically dependent on early anti-inflammatory treatment, nursing care, comfortable well-bedded housing and, where indicated, oxygen supplementation. Survivors may carry chronic lung pathology that impairs welfare throughout life.

What You Can Do

Implement BRSV vaccination programmes in at-risk dairy and beef calf groups before housing
Treat all suspected BRSV cases promptly with NSAIDs and antibiotics to prevent secondary bacterial pneumonia
Provide deep clean straw bedding and ensure excellent ventilation in calf housing without draughts
Minimise mixing of calves from different groups around housing time to reduce respiratory pathogen exposure