Anhidrosis (Non-sweating horses)

I mean, no sweat, as in your horse has stopped sweating. But, of course, you will never know what I’m talking about if you live in the latitudes where it never gets above 85 degrees F (29.4C) or the humidity is moderate.

I wish I had a picture of the first horse I had known with anhydrosis (the medical term for non-sweating). The head and nostrils were all that I could see while his remaining body remained below the water’s surface. More common are the horses standing in front of fans, nostrils flared, rib cage heaving as they struggle to stay cool without the benefit of the cooling effect of evaporating moisture from their skin.

As a vet student at Cornell, there was not much information about this condition of horses and little was written about it. However, treatments spread about the horse world with anecdotal evidence of their effectiveness. Guinness Extra Stout ale, other dark ales, and beer are common remedies. In addition, acupuncture, the Equi-Patch, 1AC, misting fans, Ventipulman (albuterol), and prostaglandin injections all have reports of working in some horses.

Some Degree – Some Horses

No one has determined why some horses in the same environment stop sweating while others do sweat, but we know that every horse is different with different responses to triggers. And no one (to my knowledge) has determined the mechanism behind anhydrosis.

We have found a cure that seems to work in every horse we try it with, and we need your help to give us more examples of this treatment’s success. Unfortunately, it is August as I write this, and it is hot. Will you help us figure this out?

Most of you already know that we are not big fans of feeding grain to any horse, including corn, oats, wheat, and especially wheat middling, which are inconsistent in nutritional value and are very inflammatory in most horses. However, as we convinced horse owners that grains cause inflammation in the gut with unwanted behavioral events, we also heard that some non-sweating horses started to sweat. We need more numbers to confirm this, so if your horse isn’t sweating (to any degree), please try this and tell us.

What To Do

Step one – stop feeding your horse all grains, carrots, sugar, treats and red trace mineral salt licks (sugar). Instead, only feed pasture, hay (grass or legume), mined salt and water. NOTHING ELSE. Adding a handful of hay pellets or hay cubes to a bucket at “feeding time” is allowed.

Step two – wait about four days while continuing on this simple diet of grass, hay, salt and water. If the experience is true, your horse will start to sweat in about three to four days.

Step three – report back your results in the comment section of this blog.

I must assume that digestive tract inflammation, leaking gut or general malaise is behind anhydrosis. I would like to understand the physiological principles behind this, but getting effective treatment counts for horse owners. If horses start to sweat after removing grain and other uncommon sugars, then all the other benefits might also be worth considering.

Grain Intolerance

If your horse shows one or more of the following, there may be grain intolerance and gut inflammation.

  • Chronic poor body condition (thin) despite feeding large amounts of grain
  • Chronic spasmodic (non-surgical) colic
  • Squirts or dribbles fecal matter when defecating – stains the stall wall
  • Girthiness (shifts feet, swishes tail, puffs up)
  • Uncomfortable being brushed
  • Unwilling or difficult behavior on the ground or while ridden
  • Bucking or hopping when moving into the trot or canter
  • Reluctant to load into a trailer or difficult when trailering
  • Non-sweating to any degree

According to reports from my clients, these conditions resolve in horses by taking the 2-week no-grain challenge. So take the 2-week no-grain challenge with your non-sweating horse and post the results. No harm in this and no cost either. You can’t lose, though your horse might sweat a bit.

This video is of horses with a high respiratory rate. The 2nd horse has anhidrosis.


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