NO SWEAT

It’s a hot, sticky morning in North Carolina, and you and three friends decide to ride in the mountains to cool off. You go early so you can be back at the trailers by the time the day really heats up. Still, in the parking lot after the ride, you notice something: Which of these horses is showing the red flags of a potentially serious problem?

a. the Quarter Horse with frothy sweat under his breastplate

b. the Appaloosa, who is drenched in clear sweat but is drinking from his bucket

c. the Thoroughbred, who is sweating only a little under his saddle and is “panting” like a dog

d. the Arabian, who isn’t sweating much but can’t wait to get at his hay and water Answer: c. the Thoroughbred. A horse who isn’t sweating when others around him are may have anhidrosis, the inability to sweat. The causes of anhidrosis are not well understood, although the condition usually develops in horses who sweat for prolonged periods of time in very hot, humid conditions. In effect, the horse’s thermoregulatory system shuts down, and even slight exertion in hot weather can cause dangerous overheating.

An affected horse may sweat a little under his mane or under tack, but his coat remains mostly dry despite exertion in hot weather. He may breathe forcefully through his mouth in an effort to cool himself, and he may be lethargic and uninterested in food or water. He needs to be cooled off promptly: Move him to a shady area, and douse him with cold water.

Call your veterinarian if you suspect your horse may be developing anhidrosis. There is no proven treatment, but you’ll need to take long-term measures to keep him as cool as possible in hot weather. In some cases, relocating the horse to a cooler climate may be the best option. As for the other horses described above, the amount and quality of sweat they produce can vary according to their individual levels of fitness, physiques and other factors, but as long as they are alert, eat and drink readily, and recover fully from exertion within an hour or so, they are probably just fine.