Keep Your Horse Cool in the Heat

Sweltering summer heat is more than just very uncomfortable for your horse. It's as much a health hazard for your horse as it is for you. Young, old or ill horses are least equipped to deal with extreme heat.

Sweltering summer heat is more than just very uncomfortable for your horse. It’s as much a health hazard for your horse as it is for you. Young, old or ill horses are least equipped to deal with extreme heat. But if you don’t manage your healthy adult horse, he could easily get into trouble, too, with dehydration, weakness, colic, poor exercise tolerance-even heatstroke.

Here are some bare minimum measures you should take:

  • Keep clean water in limitless supply available 24/7.
  • Make sure plenty of shade from trees, shelters or run-in sheds is available.
  • If a herd situation, observe carefully to make sure weaker, older or less-dominant horses are not being chased away from water or shade.
  • If you provide free-choice salt, horses should be eating at least 2 oz./day. Weigh your blocks or bricks every two weeks to make sure. If they’re not consuming this much salt on their own, start adding it to their feed. If not feeding grain regularly, make a small daily meal of soaked beet pulp or wheat bran with 2 tablespoons of salt added.

With really bad conditions, consider one of the following:

  • Bring the horses in during the hottest part of the day and treat them to a hosing.
  • Some horses really enjoy and will use a sprinkler system. Keep it outside your pasture/paddock fencing and set it to spray into the pasture.
  • Set up large fans in your run-in area. (Make sure cords are safely out of reach of chewing, curious horses.)

Quick Cooldown

An overheated horse, either from exercise or simple heat exposure, needs aggressive cooling. It is simply not true that you can’t use cold water on a hot horse. That’s a myth. In fact, such cooling may prevent a life-threatening condition from developing.

Using cold water from a hose, run water over the horse’s chest, the jugular grooves of his neck, and the lower legs. These areas have many superficial blood vessels that can be rapidly cooled by the water and will carry the cooled blood to the interior of the horse.

Once the horse seems less distressed (breathing eases), progress to hosing the entire body. Continue the hosing until the water running off underneath the horse’s body feels cool. This means the water is no longer picking up large amounts of heat from the surface of the skin.

The horse should then be slowly walked in a shaded area. Observe him carefully to make sure the respiratory (breathing) rate doesn’t climb again or that the horse begins to sweat. If this happens, repeat the cooling process.

Offer tepid water at frequent intervals throughout this process. If the horse is very distressed at first, or breathing/panting heavily, he probably won’t drink. Keep trying.

Black/brown horses and overweight horses will have the most trouble regulating their body heat. Foals and older horses may also be less heat tolerant, and horses with Cushing’s disease very often have trouble regulating their body heat. Watch these high-risk groups very carefully for signs of extreme depression, weakness, drenching sweat or failure to sweat, and even panting. If these occur, go to “quick cool” (see sidebar).

With sweltering heat, if someone isn’t around to observe the horses during the hottest part of the day, it may be best to confine them to the barn or a small area you know has adequate shade. Horses lowest in the pecking order should definitely be considered for special treatment.

It’s also normal for appetites to drop off during periods of extreme heat. If this happens, don’t panic. Your horses will start eating again when they feel more comfortable.

Because of its high water content, grass is the ideal food. If your horse doesn’t have enough grass available for it to be his main food, try tempting him with carrots, celery, apples, watermelon, squash or salad greens added to a high moisture mixture of soaked beet pulp and wheat bran.

Start with small meals if your horse isn’t used to these feeds. Adding about 1 teaspoon of salt per pound of the mixture improves appeal and is a good way to get that needed salt into your horse.

Sweating is the most important mechanism horses have for eliminating excess body heat. It’s therefore important to know if your horse is sweating normally.

As a rule, dark horses (like dark clothing) hold more heat. They will sweat more easily and more profusely than light-colored horses. Overweight horses heat up faster than slimmer ones because the layer of fat is an insulator, trapping body heat. They will sweat more and at lower air temperatures and work levels.

Unfit horses usually sweat earlier, sweat more, and have more frothy, sticky sweat than fit horses doing the same level of exercise. Horses just loafing in the field or barn in hot weather will often have a light layer of sweat, just like we do when outside in the heat. You may or may not be able to see this, but you can usually feel it.

Very young foals (first week or two of life) may not regulate their body temperatures very efficiently and should be protected from extremes of heat by making sure they have adequate shelter from the sun.

Older horses, in particular horses with Cushing’s disease, also often have trouble regulating their temperature. This may be seen as excessive sweating and panting or exactly the opposite, failure to sweat (anhidrosis) with panting and distress. (See “Anhidrosis” in the June issue of Perfect Horse.) Horses moved from northern areas to the deep South may also develop anhidrosis. These conditions call for aggressive and frequent cooling, including hosing and the use of fans.

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