Extreme heat guidance for horses

Why heat awareness matters

Horses are highly susceptible to the effects of extreme heat, particularly when combined with exercise or transport. Without proper care, heat can lead to dehydration, heat exhaustion, organ failure, or death.

Hydration

• Horses may consume up to 50 litres of water per day in hot weather, more with exercise.
• Always allow immediate access to water after exercise - this does not increase the risk of colic.
• Provide multiple clean water sources and monitor intake.

Signs of dehydration

Be alert for:

• Reduced urination or dark urine.
• Dry skin or dry mouth.
• Fewer or harder droppings.
• Dull, sunken eyes.
• Dark or tacky gums.
• Lethargy or dull behaviour.
• Prolonged skin pinch test result.

Heat exhaustion

Heat exhaustion can occur rapidly, especially after work or travel in hot, humid weather.

Key signs:

• Flaring nostrils and rapid breathing.
• Muscle tremors or spasms.
• Poor performance or slow recovery.
• Irregular or elevated heart rate.

Immediate action:

• Call a vet.
• Move the horse to shade with good airflow.
• Begin cooling with large volumes of cold water (see below).

Cooling

1. Apply continuous cold water

• Use a hose, buckets, or natural water sources.
• Apply large amounts over the entire body.
• Water temperature should be between 10–25°C.

2. Do not scrape water off

• Leave water on the skin to allow effective heat removal through conduction.

3. Monitor for recovery

• Continue cooling until breathing returns to normal and the horse becomes calm.
• Use a thermometer if available, though rectal temperatures may lag behind surface cooling.

Electrolytes and salt

• Supplement with 25ml of table salt per 500kg horse per day, or other equine electrolytes as per the instructions on the pack.
• Consider using a balanced electrolyte if your horse is sweating heavily or working hard.
• Offer soaked feeds and maintain access to water at all times.

Warning signs of heat induced stress

Seek immediate veterinary attention if you observe:

• Rapid breathing (more prolonged and vigorous than expected after exercise).
• Muscle tremors or collapse.
• High body temperature.
• Staggering or ataxia.
• Profuse or absent sweating.
• Restlessness or lethargy.
• Irregular heartbeat.

Travelling in hot weather

• Avoid travelling during the hottest part of the day.
• DEFRA advises not to travel horses when temperatures exceed 30°C unless in a temperature-controlled vehicle.
• Plan rest stops every two to three hours and offer water at each break.
• Take ample water and soaked feeds.
• Be prepared for breakdowns; carry extra water, ventilation aids, and contact details.
• Allow recovery time before travelling after competition—consider overnight stabling if needed.

Competing in hot weather

• Consider reducing the number of classes or withdrawing entirely based on your horse’s welfare.
• Take your own water supply and cooling equipment.
• Have support available to assist with cooling after exercise.
• Shorten or split warm-up sessions to prevent overheating.
• Use water to cool your horse pre- and post-warm-up without concern—competing with a wet horse is safe and can help maintain body temperature.

Cooling in the winter

Even in cooler months, horses may overheat following exercise. Use the same cooling principles:

• Apply cold water until normal breathing resumes.
• Once cool, dry or rug the horse as appropriate.

Cooling myths

Myth	Reality
Cold water causes heart attacks	No evidence – it is safe and effective
Scraping water speeds cooling	False – it removes cooling water from the body
Always cool from the legs up	Unnecessary – cool the whole body
Water insulates and traps heat	False – water removes heat through conduction

Key takeaways

• Always provide access to clean, fresh water.
• Know early signs of dehydration and heat stress.
• Begin cooling immediately and contact a vet in emergencies.
• Be prepared: have shade, water, and supplies ready during hot conditions.
• Make transport and competition decisions with your horse’s welfare as the top priority.

For further advice or in an emergency, contact your vet immediately.