One of the problems many horses face during the summer is the inability to sweat, a condition called anhidrosis. It is believed to be related to horses' lack of acclimation to hot and humid weather, but Dr. Ben Buchanan indicates in The Remuda, a quarterly publication of the Texas Equine Veterinary Association, that the condition develops in horses native to warmer climates, such as Texas, just as often as those imported from cooler areas.

Anhidrosis is reported to affect horses up to 20 percent in the southern United States and is more common in younger horses. Sweating is the manner horses cool themselves, and while it is under hormonal and nervous system control, little is known about why this happens to some horses and not to others. It is thought excessive stimulation down-regulates the receptors and just basically wears them out so that no sweat is produced. Some mildly affected horses will exhibit poor performance, while many seriously affected horses have a high temperature and are breathing rapidly to try to cool themselves.

A sweat test is used to diagnose the condition. Mildly affected horses can be worked in cooler parts of the day, and keeping them under fans and misters can be helpful.

Discuss with your veterinarian possible treatments and other ways to make a horse diagnosed with anhidrosis more comfortable.