Equine Influenza: Welfare Implications and Vaccination

Equine influenza causes high fever, nasal discharge, and debilitating respiratory illness — vaccination prevents most welfare harm from this highly contagious virus.

Key Facts

• Equine influenza (EI) spreads rapidly between horses via aerosol droplets
• Signs include sudden high fever (up to 41°C), profuse nasal discharge, coughing, and lethargy
• Affected horses require strict rest — return to exercise before full recovery risks cardiac complications
• Annual vaccination is mandatory for competition horses and strongly recommended for all horses
• Full recovery typically takes 1-3 weeks but permanent airway damage may occur in severe cases

Welfare Considerations

Equine influenza causes acute welfare suffering — high fever causes pain and malaise, the cough is exhausting and persistent, and the respiratory distress of severe cases is frightening. The requirement for 1 week of rest per day of fever (typically 4-6 weeks total) means prolonged restriction for horses used to regular exercise, which itself has welfare implications. Complications including secondary bacterial pneumonia and myocarditis in horses returned to work prematurely can be life-threatening. The prevention of EI through vaccination is one of the most straightforward and welfare-effective interventions available to horse owners, with highly effective vaccines available for biannual or annual administration.

What You Can Do

• Maintain current influenza vaccinations in accordance with governing body and veterinary guidelines
• Enforce strict rest during EI illness — return to exercise only after full fever resolution plus recovery period
• Isolate any horse with suspected influenza immediately to prevent flock spread
• Monitor temperature daily during any respiratory outbreak to detect EI early
• Ensure any newly introduced horses are vaccinated before mixing with your existing herd