Heat Stress: Prevention, Recognition are Key

Now that summer weather is here, it's important to make sure you aren't asking too much of your equine partner. The conditioning program you implement for your horse is a big factor in preventing dehydration and heat exhaustion.

Clinical signs of heat exhaustion include dehydration, muscle tremors, dangerously high body temperatures, weakness, heavy sweating, or anhidrosis (lack of sweating). All these can lead to collapse and death, which can happen immediately or up to several hours after work has finished.

Sweating is a good thing for the most part, as it is the horse's natural way of dissipating body heat. However, a horse can sweat away nearly four gallons of water and electrolytes in an hour in very hot weather. After a loss of more than four gallons of fluid (about 30 pounds of body weight), a horse might be classified as dehydrated. Losing nine gallons or more of water via sweating can be fatal.

Pinching the skin on the horse's neck near the shoulder can help you identify dehydration. If the skin doesn't recede immediately, some degree of dehydration might be present. The longer it takes for the skin to flatten, the more dehydrated the horse has become. Other signs of dehydration include a sunken appearance to the eyes, and gums that fail to return to a pink color after pressing with your finger.

Treatment of heat exhaustion and dehydration include shade, fans, and rapid sponging and scraping cold water from the horse to transport heat away from the body. Although old beliefs hold that ice water is harmful, heat stress studies have shown that using ice water is actually one of the most beneficial and efficient ways of cooling a hot horse. It's important to scrape the ice water away as soon as it warms from the horse's body heat, otherwise the water will actually trap heat causing the horse's temperature to increase. In emergency situations, a veterinarian might need to administer intravenous fluids.

Fitness is important because a fit horse develops a more efficient cardiovascular system, which results in more oxygen transport to the muscles and faster recovery heart rate. A fit horse will also sweat away fewer essential electrolytes and proteins.

After-effects of dehydration can include exertional rhabdomyolysis (commonly called tying up) impaction colic, and synchronous diaphragmatic flutter (thumps), all of which require immediate veterinary attention.

If your horse has major medical insurance coverage, the resulting high vet bills will be much less of a blow.

Article courtesy of the United State Eventing Association (USEA, www.useventing.com), and Broadstone Equine Insurance Agency, the Official Equine Insurance of the USEA, (www.broadstoneequine.com).

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