Bovine Respiratory Syncytial Virus: Welfare Management

BRSV causes severe, often fatal respiratory disease in young cattle — prevention through vaccination is highly effective and welfare-essential.

Key Facts

• BRSV is a major cause of severe respiratory disease in calves under 6 months
• It causes bronchiolitis and interstitial pneumonia with severe respiratory compromise
• BRSV outbreaks cause high mortality without intervention — affected calves struggle severely to breathe
• Vaccination using intranasal live vaccines from 1 week of age provides rapid protection
• Secondary bacterial pneumonia following BRSV is a major cause of welfare-relevant morbidity

Welfare Considerations

BRSV causes profound respiratory welfare suffering in young calves — the severe bronchiolitis and air trapping causes labored breathing, open-mouth breathing, cyanosis, and respiratory exhaustion. In outbreak situations, mortality can reach 20-30% without treatment, and survivors often have permanent lung damage affecting long-term welfare and growth. The condition progresses rapidly from mild respiratory signs to severe distress within 24-48 hours, making daily observation of young calves essential during high-risk periods (autumn and winter). Welfare-focused prevention using intranasal vaccination provides rapid mucosal immunity in calves before the conventional window for parenteral vaccines, making it uniquely valuable for early protection.

What You Can Do

• Vaccinate calves intranasally against BRSV from 1 week of age before high-risk autumn and winter periods
• Observe young calves twice daily for respiratory signs including increased breathing rate and nasal discharge
• Seek emergency veterinary treatment for any calf showing open-mouth breathing or cyanosis
• Ensure calf housing has adequate ventilation without cold draughts — ventilation reduces viral load
• Treat secondary bacterial pneumonia promptly with appropriate antibiotics to prevent chronic lung damage