Here's how to prevent your horse from getting dangerously overheated.
Question: My husband and I are looking forward to a week-long trail ride later this summer. We're planning to cover about 10 miles per day. There are good drinking streams along our route-but we're worried about keeping our horses cool. How do we go about that, and how will we know if they're getting dangerously hot?
Holly Vannamen
Red Bluff, Calif.
Answer: While a horse does run the risk of overheating during exercise on a hot day, he's fortunately blessed with a phenomenal cooling ability. He has a large surface area covered with sweat glands, which enables him to cool by evaporation. He also circulates large amounts of blood close to his skin's surface, which enables him to cool via heat convection when the air temperature drops. Water--and plenty of it--is necessary to keep his cooling systems up and running.
With preparation, pulse-and-respiration monitoring, and cool-down savvy, you and your horses will share a safe and memorable week on the trail. First, prepare your horse at home. Here's how:
Get your horse fit. The logic is simple-a well-conditioned horse will go farther with less chance of overheating on a long, hot ride than will an unfit animal. For at least 4 weeks before your trip, go on long trail rides (at least 2 to 3 hours), riding midday to simulate the heat of late summer.
Teach your horse to drink along the trail. At your barn, accustom him to drinking from a variety of containers. On your practice rides, allow him to drink from streams or natural pools after he's worked up a thirst.
On the trail, use these techniques to keep your horse from becoming overheated:
Get a baseline heart rate. Your horse's heart rate is the best indicator of overheating. First, get a baseline by recording his normal rate at rest, after an hour's ride, and following a long climb. Here's how: Buy an inexpensive stethoscope and a watch with a second hand. Place the stethoscope on his lower chest, behind his left elbow. Count the beats in 15 seconds, then multiply that number by four-that's his beats-per-minute (or bpm). Normal rates are 30 to 40 bpm at rest; 60 to 80 bpm after 1 hour of walking/trotting; 100 to 120 bpm after a long, uphill climb.
Monitor your horse's respiratory rate. Normally, your horse's heart rate is three to four times his respiratory rate. For example, if his heart rate is 80 bpm after 2 hours of easy riding, his respiratory rate would normally be 20 to 27 breaths per minute. Take his respiratory rate by counting the number of times his flank goes in and out in 15 seconds, then multiply by four to get a breath-per-minute rate. Normal rates (in breaths-per-minute) are 4 to 6 at rest; 20 to 30 at an easy pace; as high as 60 after exertion. Red alert: If your horse overheats, he may experience an inversion-that is, his respiratory rate exceeds his heart rate. If he doesn't show signs of recovery from an inversion after a 10-minute rest, he needs to continue to rest and cool down; immediately lead him back to camp. There may be an underlying problem; consult your veterinarian.
Check for dehydration. First, do the skin pinch: Take a fold of skin on your horse's neck between your thumb and forefinger, and release it. It should go flat in 1 to 2 seconds. If it doesn't, he's dehydrated. Second, check his gums: They should be pink and moist, not gray and/or dry. If he fails these tests, he needs more water--now. Immediately take time out, cool him down, and see that he drinks.
Stop at hilltops. Your horse will exert the most when climbing hills. Let him rest at the top, under shade if possible, and take advantage of any breeze to cool down. At longer rest stops, remove your saddle and pad to increase the amount of exposed surface area.
Take water breaks. After riding for more than an hour, encourage your horse to drink. Cool him down by soaking a small towel or sponge in water and placing it over his poll. Then sponge water along the underside of his neck and down his lower legs, where there are a lot of major blood vessels close to the skin's surface.
Greg Fellers, DVM, a graduate of the University of California-Davis School of Veterinary Medicine, has been a large-animal practitioner (primarily horses) for almost 30 years. A member of the North American Trail Ride Conference and the American Endurance Ride Conference, he's been "vetting" rides for 20 years, including the Tevis 100 Mile Ride. He co-owns Loomis Basin Large Animal Services, in Loomis, Calif. This article first appeared in the August 2000 issue of Horse & Rider magazine.
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