Horses in the Heat



“If you saw a heat wave, would you wave back?” – Steven Wright

For all of the fun that the summer sun brings, hot weather poses a big challenge to the horse (and its owner).  Simply stated, horses really aren’t hot weather creatures, and working them in the heat of the day risks some real dangers.

When it comes to handling high temperatures, the biggest problem for horses is their geometry.  The horse’s body is big and wide, and doesn’t dissipate heat well.  There’s very little body surface, relative to the size of their body, from which they can get rid of heat.  So, the organs inside the body stay hot even while the body surface tries to radiate heat as fast as it can.  People take the added step of covering up the body surface with a saddle and pad – or worse, forget to take off their ever-present blankets – which further reduces the area from which body heat can be lost.

The only other way that horses can try to cool off is to perspire (sweat).  As the water in sweat evaporates, it cools the horse, slightly.  But sweat also causes the horse to lose body water and body salts (electrolytes), so, while it’s an effective means of cooling, over time, excessive sweating can have some bad consequences for the horse in terms of dehydrations, and, in severe cases, weird abnormalities associated with electrolyte loss.

With it being fairly well accepted that an ounce of prevention is worth a pound of cure, the best thing to do is to avoid riding your horse in the heat entirely.  If the temperature is pushing up into the 90s, ride early in the morning, or late in the evening, and don’t put your horse at risk.  Keep him in a stall, and, ideally, put a fan in the stall to keep the air moving (but make sure he can’t reach the cord – electrocution is no fun, either).  If your horse is in pasture, make sure that there’s cover, or shade, so that he can get out of the sun.

During the day, make sure that your horse has free access to fresh water.  Check the water temperature, too – I’ve seen situations where pipes bringing water to automatic systems got hot, and the water in the bowl was too hot for the horse to drink.  If there are multiple horses in a pasture, put out several water sources, so no one gets left out.

For horses that are resting, or not exercising excessively in the heat, electrolyte supplementation generally isn’t needed.  Horse feed contains lots of salts, and, assuming that the horse is eating normally, and the feed is good, there shouldn’t be any need for supplemental salts.  Giving a scoop of electrolytes in the feed – or a tube of paste in the mouth – isn’t harmful, but it’s not really doing much, either.  If you’re so inclined, you can make your own electrolyte mix by combining equal parts of iodized salt and “Lite” salt, and save a bunch of money in the process.  A tablespoon a day should be more than enough.

If you are riding your horse in the heat, take some simple steps to make sure that he stays as cool as possible:

1.    Always allow your horse to drink while he’s exercising. There’s an old myth out there that says horses shouldn’t drink while their working, but that myth is not only wrong, it’s dangerous.

2.     Make concerted efforts to cool your horse down, particularly if exercise is going to be prolonged (endurance, eventing, etc.). Water is your horse’s best friend when it comes to cooling.  Hose baths, followed by scraping – which helps the water evaporate – are wonderful.  Sponging the horse with a cold, wet sponge can help, too.

3.      Remove insulating materials, such as saddles, blankets, or pads.

4.      Consider clipping your horse if he’s got a heavy coat – it’ll help water evaporate more easily.

5.      Pink skinned horses can sunburn – consider using sun-blocking ointments, such as zinc oxide, on pink muzzles.

Heat stroke can happen in horses, and, if it does, it’s an emergency that should require immediate veterinary care.  Watch for signs such as increased breathing rate, or panting (normally, horses, breath 4 – 16 times per minute), increased heart rate, profuse sweating – or worse, no sweating at all, from a condition known as anhydrosis, for which there is no effective cure – elevated body temperature (above 102 degrees F), or depression.

Fortunately, most people seem to be pretty sensible when it comes to riding and exercising horses when it’s hot outside.  Once a year, it seems that I’m treating a horse for problems caused by owners who were careless with their horses in the heat.  Be careful, because what you might think is a perfect, warm day for a long ride can be torture for your good friend.

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