How to cool down your horse

With the indisputable rise in global temperatures, periods of hot weather are happening more frequently in the UK, too. But what impact does this have on your horse? For a start, it’s increasingly important to be able to recognise the signs that your horse is feeling too hot and also to then know how to cool him quickly and efficiently if he is.

Normal temperature for your horse

Horses are homeothermic animals, meaning their bodies work to maintain a constant internal temperature. A healthy adult horse should have a normal body temperature of 37.5–38.5°C, and when this rises above a comfortable level, extra support is needed to lose the excess heat.

Top tip

Know your horse’s normal resting respiration rate and temperature, and time his recovery to discover how long it takes for these to return to normal in average climate conditions (normal seasonal temperatures).

Just like humans, horses do this by sweating. Sweat glands are densely packed in horse skin (810 glands per cm²), with sweat primarily exiting the skin’s surface at the hair follicles. These tubular, coiled sweat glands have a rich blood supply and numerous nerves are found close to them. However, due to their large body mass, horses have proportionately less skin surface area for dispersing that heat than humans.

Did you know?

After work, reduced oxygen and blood circulation traps heat in muscles. An inability to reduce this heat load can result in muscle damage, heat exhaustion, heatstroke and, in extreme circumstances, death.

How to tell if your horse is too hot

It pays to check whether your horse is too hot and also to know the signs to look out for…

• Is he sweating excessively?
• Is he completely covered in sweat, or is it running from his body?
• Does he feel very hot to the touch?
• Is he taking fast and shallow breaths (panting)?
• Or, is his breathing deep and laboured?
• Does he show less reaction than normal to people and his surroundings?
• Does he appear distressed?
• Are there prominent, raised veins under the skin?
• Is he unsteady on his feet (known as ataxia)?

Having observed him, how do you decide whether your horse is simply hot or is suffering from more extreme heatstroke or exhaustion? The following signs may indicate either heatstroke or heat exhaustion, and, in either case, your horse will require prompt veterinary assessment and the appropriate measures to be taken …

• A reduced appetite and not appearing thirsty
• Dark mucous membranes
• Muscle spasms
• Dark urine or the inability to pass urine
• Lethargy

Thumps, which is a condition that produces irregular contractions of the diaphragm, giving a thumping noise similar to a human hiccup. Correctly referred to as synchronous diaphragmatic flutter, thumps cause the diaphragm to spasm in the same rhythm as the horse’s heartbeat.

Top tip

Horses can overheat without sweating. This condition, when the horse loses ability to sweat, is called anhidrosis and if you suspect it, call your vet immediately.

Steps to cool down your horse

Cooling a horse correctly is not only about the application of water. In fact, in some circumstances water may not even be required for cooling. Follow these steps for rapid, but non-emergency cooling of your horse…

• Untack, noting his respiration rate by watching his ribs – a full breath is counted as the rise and fall of the ribcage. Normal resting respiration rate is 8–16 breaths per minute.
• If possible, ask a helper to walk him while you gather your equipment.
• Find a shaded area.
• Apply water, ideally at less than 15°C – the colder the water, the less you will have to use.
• Soak the horse thoroughly. His large surface area means it’s not sufficient to dampen him – he should be saturated.
• Effective cooling is about continually covering his whole body with cold water. It isn’t necessary to focus on specific areas such as the neck, hindquarters or between the legs and there’s no need to scrape away the water and sweat.
• Continue to monitor his breathing and demeanour.
• Check the temperature of the water running off him. If it’s higher than when you applied it, continue wetting him, as this shows his body heat is still high enough to warm it.

Did you know?

Sweat is made up of proteins, electrolytes and significant amounts of water.

Cooling your horse down in an emergency

Aggressive cooling should be used in an emergency if the horse is ataxic or showing signs of heat exhaustion. If not treated quickly and effectively, there’s a risk of death from damage to the kidneys, heart, lungs, brain and muscles, so it’s imperative you call your vet immediately for advice.

Continue with constant, copious water application for rapid cooling until your vet arrives.

It’s worth noting that a horse with heatstroke can be difficult, or even dangerous to handle, so, for your own protection, ensure you’re wearing a helmet, gloves and sturdy boots.

Myth busting

There are many myths surrounding the cooling of horses, so be sure to stick to the following advice…

• Mesh and fleece rugs do not cool horses. You can buy rugs that must be soaked in water or contain alcohol, and although these will make the horse more comfortable, they won’t cool. It’s fine to drench a fly rug in water and leave it on your horse in hot weather to keep him more comfortable.
• Applying ice-cold water will not give your horse colic, laminitis, muscle or kidney damage, or a heart attack.
• Leaving water on the horse will not make him hotter but, rather, will allow him stay cool for longer.
• Scraping off water is not helpful. It wastes time that could be better used applying more water for cooling by conduction. It also wastes water when it’s in short supply, such as at a show.
• A horse who’s not sweating can still be too hot, as, although rare, anhidrosis can occur.

Our experts

Helen Reynolds is an FEI Equine Permitted Therapist and Testing technician and an Equine Thermographer. She runs her own practice and a rehab yard.

Emma Cornish is a BGA certified freelance groom. She’s worked in rescue, rehabilitation, eventing, the veterinary sector, and at the highest levels of equestrian sport.