WHEN “NO SWEAT” IS TIME TO WORRY

Like humans, horses rely largely on the ability to sweat to stay cool when the mercury skyrockets. Builtup heat is dispersed when the sweat evaporates from the skin’s surface. It’s an ingenious system that, for the most part, works reliably and well. However, if your horse stops sweating on days when other horses around him are soaked—especially after exertion, or on humid days that tend to limit the evaporation of sweat—he may have a serious condition known as anhidrosis.

Though its precise cause is unknown, anhidrosis is believed to be triggered by overstimulation of the sweat glands by stress hormones in hot, humid conditions. The exhausted glands simply

“give up” and the horse loses the ability to sweat, either partially or entirely. Sometimes sweating function improves after prolonged period of cool “rest” for the sweat, but often it never does.

A horse with anhidrosis might be damp under the saddle and bridle but still have a dry coat. He might also be lethargic and show sign of heat stress, as well as breathing hard through his mouth as he attempts to cool himself. This signals the shutdown of his thermoregulatory system, with dangerous overheating just around the corner.

To immediately help a horse with anhidrosis, move him to a cooler location, drench him in cold water and call your veterinarian. To manage the condition long-term, resolve to invest in extra stall fans, water buckets and perhaps misters; you’ll also want to curtail your horse’s activities during the heat of the day. Besides addressing an affected horse’s environment, supplementation of targeted electrolytes based on irregularities identified in blood analysis can sometimes help jump-start the sweating. If all else fails, relocating the animal to a cooler, less humid climate might offer the best chance at restoring normal thermoregulation.