Keeping Your Horse Safe in the Heat

The 1996 Atlanta Olympics made many of us more conscious of the impact of heat on our horses. Heat stress is not just a factor in highly-tuned equine athletes; it may pose even more of a hazard if your horse isn't as well conditioned as he should be. Whether you're a daily rider or a weekend equestrian, the summer heat and humidity require extra precautions so your horse doesn't overheat during or after workouts.

Metabolism in horses is highly inefficient, with much more of muscle work, up to 80 percent, converted to heat and wasted. This sends a horse's body temperature way up, not only during his workout but for as long as 10 minutes after he's done. As his temperature rises, he begins to sweat, which allows the heat to transfer from the muscles to the surface of his body and dissipate as the sweat evaporates.

This process, which allows him to cool, becomes more difficult in high heat and humidity, especially when there's no breeze. When there is a great deal of moisture in the air, your horse's mechanism for heat loss, the evaporation of sweat, doesn't work as well. It is even more important to take some precautions during this type of weather to keep your horse cool during and after riding.

Although most of the research done in this area has focused on horses participating in three-day eventing because of the demands of the sport, the risk to more heavily-muscled animals such as those used in dressage and Western work can be just as great. It is significantly more difficult for those horses to cool themselves because of their dense builds.

Learn to Recognize Signs of Overheating

Horses follow a predictable pattern of symptoms when they overheat. When the horse is under saddle, the signs are harder to see, but a horse that is sweating, acting tired, stumbling, missing jumps, refusing work, having trouble breathing under saddle or trying to take extra breaths may be overheating.

The physical signs with the horse pulled up are easier to see. First, the animal responds to overheating by fast shallow breathing (hyperventilation) to dissipate heat through the lungs. This fast breathing will persist beyond the 10 to 15 minutes expected as a cool out time on a hot day. The horse becomes preoccupied, anxious, seeks water and will readily drink a gallon or two in most cases. At this stage, horses should be sweating from head to toe. If they are not, they may have a condition called "anhydrosis," which is a relative or absolute inability to sweat. These horses hyperventilate without sweating and require immediate cooling with ice water.

The body temperature of an overheated horse can exceed the normal 104 to 105 degree Fahrenheit that we expect after a hard workout, even going up to 107 F for longer than expected. High temperature like this can seriously impair tissue and even brain function. The first thing you want to do is stop work, take your horse to shade, loosen the girth and pull the bridle. Pour or sponge cold water or ice water onto the head, neck and chest. This will quickly reverse the signs. If there is wind, the horse will cool faster. If not, a fan helps, as shown in the Atlanta Olympics. Otherwise, use lots of water.

If the overheating gets worse, the horse may appear depressed, distant, even delirious. The respiratory pattern takes on a characteristic change, from fast and shallow to slow and deep labored breaths. This is an ominous sign and should be considered an emergency. At this point, the horse is failing to keep up with the heat overload and there can be harmful consequences.

If this stage is permitted to go on, the horse will become severely dehydrated, lethargic, weak and will show signs of electrolyte disturbances such as hypocalcemia (twitching, tremors, stiffness, falling down) or hypokalemia (arrhythmias, fast heart rate) or hypoglycemia (strange behavior, star-gazing or seizures). Seek immediate veterinary attention. Intravenous fluids, electrolytes, calcium and glucose may be administered.

Fortunately, most horse people will never witness these severe symptoms. It is far better to prevent the problem.

Tips for Summer Safety

• If your horse is not conditioned, don't ride hard when it's extremely hot or humid.
• Give your horse frequent walk breaks and monitor his sweating. If he isn't sweating within several minutes of work, stop.
• If possible, ride during the cooler hours; early in the day or in the evening.
• Clip the summer coats of heavily-muscled horses every three weeks to about one-eighth inch to help keep them cool.
• Before you ride, check to see that your horse is drinking water. Some horses are as fussy about drinking warm water in the summer as they are about drinking cold water in the winter. So if you have a water bucket that sits outside in the sun, they may not be drinking enough. Try to keep outdoor water buckets in a shady area and keep the water fresh.
• If your horse becomes unusually hot during a workout, don't be afraid to apply cold water to his neck, belly and hindquarters. Research has discounted the theory that cold water on a horse's back will cause cramping. When you're at a show, have someone bring a bucket of cool water and a towel to the ring. It can be wet, wrung and draped on your horse's neck for a quick cool-down between your warm-up and classes.
• Use a light saddle pad. A heavy, fleece pad acts as a heat insulator, especially under the saddle. Look for lighter weight, cool-weave pads for summer. They provide the same protection to your horse's back and allow for better heat dispersal.
• Add some electrolytes to your horse's feed when he's working in hot weather. You can make your own by mixing 3 parts table salt to 1 part potassium chloride, available as Lite Salt in the grocery store. Add 1 to 4 tablespoons to your horse's daily feed ration. Or you can buy ready-made electrolyte supplements from your feed store or catalog.

Hay is rich in potassium, so it is more critical to provide adequate sodium chloride, since neither hay nor grain provides much, and salt blocks are no substitute for adequate salt provision. Four to five tablespoons of regular table salt per day (80 to 100 grams) will provide a working horse that sweats with enough supplemental sodium chloride.

It's better to feed electrolytes by top-dressing them on your horse's food than mixing them in his water. Some horses will refuse to drink supplemented water and, even if they do, they don't get it all unless they drain the bucket. If you're afraid electrolyte powder will fall to the bottom of the feed bucket and your horse won't get it, sprinkle the feed with a bit of water first.

• Finally, the same cautions apply to riders as horses. People take extraordinary measures to keep their horses cool, but faint from heat prostration coming off a cross-country course. Freeze a bottle of water the night before a show, workout or a long ride and take it with you. It will thaw slowly, and provide you with cool drinking water for several hours.