Anhidrosis or "dry coat" is the decreased ability or complete loss of ability to sweat. Since horses are one of the species that rely on sweating to help keep their body cool, not being able to sweat can cause them to perform poorly or even collapse. Horses that live in hot, humid conditions no matter the age, gender and breed are most likely to gradually develop this condition.

What can be done about it?

The underlying cause of anhidrosis remains unclear. Experts believe either something is wrong on the stimulation end (such as with the neurotransmitter adrenaline) or something is wrong on the receptor end (such as decreased numbers of receptors or decreased sensitivity of these receptors). While no treatment exists, there are supplements that support healthy sweating by supplying electrolytes, neurotransmitter precursors and specific herbs.

What else do I need to know?

Some horses with anhidrosis regain the ability to sweat when moved from the hot, humid climate to a cooler, drier one yet others don't. Additional tips to help keep horses cool include:

When bringing your horse to a hot, humid climate, allow him to acclimate with 10-14 days of turnout and light work before returning to regular training and showing
Get your horse "legged up" or conditioned with interval work or distance riding before the hot months so you don't have to work on basic fitness then
Work your horse during the cooler parts of the day usually morning or evening
Observe your horse closely during exercise for signs of overheating such as rapid breathing or panting, rapid heart rate and fatigue
Cool your horse off with water as cold as he will tolerate and quickly scrape it off. Keep reapplying and scraping until his temperature has returned to normal
Provide cool air with good barn ventilation and fans

About Dr. Lydia Gray