Horses suffer in the heat just as people do. Hot weather causes discomfort and can lead to heatstroke, sunburn and dehydration. All horses need to be protected from heat, but animals with darker colored coats, foals, and older or unfit animals are more vulnerable. Horses with Cushing’s syndrome may also suffer greater ill effects due to the thickness of their coats.
How Horses Cool Themselves Down Naturally
Horses lose 25% of their heat through breathing, which is why fast breathing or panting can be a sign that they are overheating. Drinking water is another important way of naturally cooling down, and 25-30% of heat is lost through sweating.
Foals do not have a fully developed sweat gland system so they are more vulnerable to overheating. A thin layer of sweat over the skin is normal for a horse, but overweight or unfit horses will sweat more than this in an attempt to reduce their body temperature. Horses suffering from anhidrosis can have particular problems in the heat, as they cannot sweat enough.
Horses also lose heat through blood vessels that pass close to the surface of their skin. This can happen by conduction – for example the heat passes to water when the skin is wet – or convection, when the heat passes through the skin into the air. Evaporation also cools a horse, particularly when sweat evaporating off the skin cools it down, but also from water evaporating off the skin after a horse has been washed. This is why using water and increasing the air flow are effective ways of cooling a horse down.
How You Can Cool Down A Horse in The Heat
Shade
Provide shade during the day. This can be a tree, a hedge, or a field shelter. But bear in mind that the sun moves around during the day so the amount of shade may vary. Also, if there is more than one animal, the smaller or weaker animals may be pushed out by the others, so observation is needed to make sure that all horses can access the shade.
If the horses are stabled in a barn on a turn-out schedule, avoid turning them out at the hottest parts of the day and instead get them outside in early morning and late evening.
To increase airflow inside, consider installing a fan within the barn. Avoid pointing the fan directly at a horse as this might make them uncomfortable, and ensure they are not stressed by the noise. Also check that cables are safely stowed away from curious chewing mouths.
Drinking Water
Horses need access to fresh clean drinking water twenty-four hours a day. Remember that in hot weather horses can drink twice as much as they would normally. If providing water manually in buckets, provide plenty of it and check the supply frequently. If using an automatic trough, check on a regular basis that it’s working.
It is a myth that you shouldn’t give horses cold water to drink. One tip, in fact, is to freeze gallon jugs of water and add them to the drinking trough which will keep the temperature of the water down. Check out our guide on keeping horse water cool if you’re concerned about the temperature of your horses drinking water in the heat.
Washing and Hosing
Hosing or sponging will immediately cool down a horse that’s too hot. Hose or wash down a horse after exercise in hot weather, and scrape off any sweat. If the animals have access to a pond where they can paddle or swim, so much the better. Some owners use a sprinkler system. A misting system is another option – these are used to keep horses cool during the Olympics. Try to provide a shaded area with good airflow for horses to be in after they’ve been washed, as this will help the evaporation and heat loss process.
Another myth is that a horse shouldn’t be cooled down using cold water. Having said that, if it’s the first time they’re being hosed, they might be afraid and need some encouragement.
Sun Cream
Horses can suffer from sunburn on any skin which is directly exposed to the sun, such as bare patches, the tips of the ears, the muzzle and the heels. Grey coated horses are particularly vulnerable to sunburn. Apply cream to these exposed areas, making sure to test it first. Horses might need some gentle encouragement when this is done for the first time.
Replace Electrolytes
When animals sweat, they lose salt and other minerals which evaporate with the sweat, and these need replacing. If possible, keep track of how much salt the animal is consuming each day; as a rough rule of thumb this should be about two ounces in summer months and one ounce in the winter, but it depends how much the horse has been working. More details are on this website.
A salt lick is one approach. If the horse is not consuming enough salt proactively, consider adding powder or paste to its feed. Bear in mind that appetites for food might be affected by hot weather so they could eat less. So it’s also important to tempt them to eat with tasty food that they like.
When Is It Too Hot To Ride?
Riding, exercising, schooling and transporting horses should all be done with more care in hot weather. Humidity as well as temperature matters. A common rule of thumb is the ‘rule of 150’. Add up the temperature and the level of humidity. For example, if the temperature is 90 degrees Fahrenheit and the humidity is 70%, the score is 160. With a score of 150 or above, care should be taken. If the score is 170 or above, it’s probably too hot to exercise a horse.
However, all of this depends on the horse. A fit horse will be more resilient to the heat than an unfit or overweight one. If the horse has recently relocated, for example from the North to the South, they may struggle more with high temperatures. If the horse can be quickly and efficiently cooled down afterwards, this may make a difference too. It’s a matter of observation and judgment.
Exercising, Riding or Transporting Your Horse in Hot Weather
In hot weather, exercise your horses at cooler times of the day such as early morning or evening. Take frequent breaks if schooling, and provide plenty of water. Replace one long session with two shorter ones, with adequate rest time in between. Take it easy, and avoid doing anything too strenuous when the weather is hot.
If riding, try and follow routes with plenty of natural shade. Use a lighter tack, such as an English saddle or bareback pad.
If you need to transport a horse, do it early in the morning or in the evening, and keep the journeys short with plenty of stops. Ensure that the trailer vents are open so that there’s good airflow.
Problems The Heat Can Cause Horses
A horse that gets too hot can suffer from heatstroke. Symptoms of heatstroke include a fast heart rate, a high temperature, restlessness, depression, weakness, colic-like symptoms, panting, sweating too much, or not sweating at all. If the situation becomes really extreme, this could lead to stumbling, seizures, coma and even death.
Anhidrosis can occur in hot weather. This condition means that animals are unable to sweat effectively. It is thought to be caused by a hormonal imbalance and is often observed partially. This means that there might only be a minor reduction in normal sweat production, which can be difficult to spot. Anhidrosis can be treated with medication, but all the measures to prevent overheating are particularly important with a horse which cannot sweat normally.
Insects are often a problem associated with hot weather. Avoid turning the horses out in places where insects gather, and at times of day when there might be more bugs and flies. Poo-pick fields to avoid attracting insects in the first place. Lightweight breathable fly sheets are best during hot weather if one is needed to prevent bites.
How To Treat Heat Stroke and Sunburn In Horses
If you suspect heatstroke, the horse needs to be cooled down. Move it somewhere shady and hose or sponge down, scraping off any sweat. Focus on the areas where the blood vessels are closer to the skin, such as the chest, the jugular grooves of the neck and the lower legs. Then water the entire horse. Continue until the water running off the animal feels cool.
Walk the horse slowly to assess how it is. If it still seems affected, contact a vet.
If a horse has suffered sunburn, get it out of the sun and treat with a soothing cream. If the skin is crusty or weeping, consult a vet.