Anhidrosis aka Non-Sweaters

Anhidrosis aka Non-Sweaters

Whinny’s Wisdoms

Springhill Equine Veterinary Clinic

Hi everyone, Whinny here! Here in Florida, it’s been brutally hot lately! I heard my Springhill docs saying it’s even worse than a usual summer. It’s been hard on the horses too – we’ve had a bunch of horses in our area stop sweating, which the docs say is a pretty big problem. They actually want them to get gross and sweaty to stay healthy! There’s a fancy name for when they don’t sweat well enough – Anhidrosis.

Normal Sweating

It’s really important for a horse to sweat so it can keep his internal organs at a normal temperature even when he’s working hard or it’s hot outside. Horses have a lot of sweat glands in their skin, and many of them are a different type than the ones you humans have. Have you noticed that when your horse sweats, it’s often white and frothy looking? That’s because they have something called apocrine sweat glands that make sweat rich in proteins and lipids that causes them to look “lathered up”. Sweat also contains a lot of water and electrolytes like sodium, potassium, and chloride. As the water evaporates off your horse’s body, it cools him down, transferring the heat into the air. A horse’s normal body temperature is from 98.5 to 100.5 Fahrenheit. When he’s exercising, it may be elevated, but will return to normal quickly at rest.

What’s the Deal with Non-Sweaters?

When your horse has a decreased ability to sweat like he should in response to an increased body temperature, it’s called anhidrosis. Because sweating is the horse’s primary way of cooling himself, if he doesn’t sweat appropriately it can cause him to get overheated, not perform well, or even develop dangerous heat stroke. Horses lose 65-70% of body heat through their sweat, so if they’re unable to do that, it’s a pretty big deal. Anhidrosis can have a significant effect on your horse’s ability to be ridden and perform or even just function as a pasture pet.

During hot weather or hard exercise, a horse with anhidrosis won’t sweat as much as he should or might not sweat at all. He can have patchy sweat (like only under the saddle pad), a little sweat, or no sweat. He might appear to be working much harder than he should be or breathing heavily to try to cool off, even after he’s done working or just while standing around.

Springhill Equine Veterinary Clinic

Anhidrosis is a problem mainly in hot and humid, tropical kind of places, like my dear home state of Florida and other states around it. This is especially a problem when the temperatures stay high for long periods of time, and don’t drop down much at night, like the perma-summer we seem to have here in Florida. Lucky us! It’s not as common in cooler, more temperate climates, but it can happen there too, especially in heat waves. Making matters worse, when the humidity is high, the sweat is even less able to evaporate into the already water-saturated air, so it decreases how effectively sweat can cool the horse.

It’s not known exactly why or how anhidrosis happens, but it’s thought that the sweat glands get over-stimulated and so they start to work less well. The onset can be sudden or more gradual. It can happen to horses that are born in a hot climate as well as horses that are new to it. So being from Florida doesn’t protect them, unfortunately. Between 2-6% of horses are estimated to have anhidrosis. No links to specific breeds, ages, colors, or sex have been identifiedthe risk is equal for all horses.

Chronic anhidrosis has been linked to atrophy (degeneration) of the sweat glands, leading to a permanent loss of the glands’ ability to produce sweat. Researchers are looking into associations with decreased excretion of chloride through the urinary system and in sweat glands, but this is still being investigated.

Recognizing and Diagnosing Anhidrosis

Because some horses with anhidrosis still sweat a bit, it can be tricky to recognize if your horse is affected. Some areas of the body can continue to sweat, but not enough to cool the horse sufficiently. For example, a horse with anhidrosis might continue to sweat under his mane or saddle pad.  You may notice first that your horse doesn’t perform well in hot weather. He may take longer than normal to recover after exercise or breathe heavily even when standing in the shade. He may have a higher-than-normal pulse or temperature.

Here are some things to watch for:

  • Lack of sweat, or a small amount of sweat, in situations when other horses are sweating a lot
  • Coat is dry and clean to the touch
  • Fast or labored breathing, especially when standing around not working
  • Flared nostrils
  • Low energy or fatigue
  • Slow ability to cool down after exercise
  • Increased body temperature (especially serious when it’s higher than 104)
  • Seeking and remaining in the shade (especially if food is elsewhere)
  • Sometimes, eating or drinking less than normal
  • In chronic cases dry, itchy or flaky skin. Sometimes there is hair loss.

My docs can often diagnose a horse based on their physical exam and the signs your horse is showing. If the diagnosis isn’t certain, there is a test they can do to check the amount of sweat your horse is able to produce. For this test, my doc injects a small amount of a medication called terbutaline into the horse’s skin to elicit sweating in that spot. That tests the amount of sweat your horse can produce compared to a normal horse.


So if your horse is a non-sweater, what to do? Well sure, if you move your horse to a cooler climate where hot, humid weather is less likely, they will certainly be more comfortable. Many horses will start sweating again when they are in a cooler environment, and that is the only surefire approach. But, it may not be a realistic option for many people and horses.

One of the simplest things to try is an electrolyte supplement, which is a good idea in the summer even if your horse sweats normally. Several remedies that have been tried over the years, with variable success, including commercial supplements such as One AC or Platinum Refresh, and even dark beer such as Guinness. Most of them are fairly safe to try, though they may or may not work. At Springhill Equine, we often use a combination of acupuncture and Chinese herbal therapy and find that can be quite successful in some cases.

Springhill Equine Veterinary Clinic

Here are some other ways to keep a non-sweater more comfortable:

  • Keep him in a stall or shaded paddock during the day. A severely affected horse may not be able to tolerate turnout on hot days.
  • Provide fans, misters, or a sprinkler. Some horses will cool off in a pond if they have access to one.
  • Make sure he always has cool water to drink
  • Keep work to a minimum during the hot times of the year and ride early in the morning

It’s better to prevent your horse from getting overheated than to have to treat him if he does, but if you get in a bind here are some steps to follow

  • Move him somewhere shady
  • Hose him down with a continuous flow of cool water or sponge him repeatedly with water from a bucket filled with water and ice
  • Use portable fans
  • Offer him cold water to drink
  • Take his temperature, heart rate, and respiratory rate if you can
  • Call my doc!

So if your horse is all stinky and sweaty after a ride, and you have to bathe him and wash your saddle pads yet again, don’t grumble about it, be happy about that sweat!

Until next week,


P.S. Have you heard the exciting news? The Adventures of the Horse Doctor’s Husband 3 is available for pre-order! You can reserve your ebook today, and it will release on Sept. 8th! If you prefer a paperback or hardcover, they’ll be releasing on (or a bit before) Sept. 15th, just a week or so away! Click Here to go over to the book page on my website for links to purchase.

Justin B. Long

Whinny’s Wisdoms is the official blog of Whinny the Clinic Mouse at Springhill Equine Veterinary Clinic in Newberry, Florida. If you liked this blog, please subscribe below, and share it with your friends on social media! For more information, please call us at (352) 472-1620, visit our website at, or follow us on Facebook!

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Summer Prep for your Horse

Summer Prep for your Horse

Tuesdays with Tony

You all know how much I love laying around outside basking in the sun, but the last few weeks have been a muggy mess! This past weekend gave us some relief, but that was just a tease. Winter’s gone and summer has arrived, along with all those fun Florida summer things that horses and horse owners get to deal with. Fortunately for you, I’m an expert on summer and the problems it can cause for your horse, and I’m here to help you prepare for a happy, safe summer ahead.

Heat and Humidity

You don’t have to live in Florida to be affected by the heat and humidity of summer. Horses throughout the entire world are affected every year by anhidrosis, which is the inability to sweat. The cause of anhydrosis is unknown, but humidity does seem to play a role. If you know that your horse is a non-sweater, I highly recommend getting a jump start on helping them deal with it before the heat of summer.

There is excellent data on acupuncture treatment for non-sweaters. I’ve seen it myself; a horse comes with difficulty sweating, they have a few acupuncture treatments, and while they may not be in a full-blown dripping sweat, they are indeed sweating. I’ve also noticed that non-sweaters who are treated with acupuncture really seem to handle the heat much better. It is complete voodoo magic in my opinion, but it’s voodoo magic that works.

Springhill Equine Veterinary Clinic

You may not know if your horse is a non-sweater yet, and that’s okay! At the first sign that your horse is shutting down and not sweating, call your veterinarian. They can talk to you about treatments, products, and lifestyle changes that may make your horse’s life as a non-sweater easier.

Horses that don’t sweat aren’t the only ones that struggle with the heat, and it can be exhausting. That’s why it’s so important to be aware of the appropriate times to work your horse. Early in the morning and late in the evening tend to be the coolest. It can also be beneficial to hose your horse down prior to exercising. An extended warm up and cool down will ensure your horse recovers well after exercise, thus preventing problems associated with heat stress.

An overheated horse is prone to colic from dehydration. They can also collapse from overheating. Believe it or not, horses can overheat even if they are not doing any type of exercise. That means a horse could be standing out in his favorite pasture and get overheated. Ensuring there is fresh cool water available, ample shade, and if possible, fans, can be extremely useful in preventing a horse from overheating. I’ve even heard stories about horse owners setting up sprinkler systems for their horses to stand in during the day, and those silly horses do, and LOVE it. Whatever floats your boat, I suppose.


I know how much you all just love the bugs. Flies and mosquitos are just great, aren’t they? How about gnats? And oh, my goodness, it’s literally been raining caterpillars recently. Flies and mosquitos are a year-round thing down here in Florida and are enough to drive any horse and horse owner bananas.

If you’ve ever had a horse that’s had a summer sore, you know what I mean when I say they are a pain in the rear end. Preventing summer sores is key. I highly recommend your horse wear a fly mask, if not 24/7, at least during the day when the flies are most busy. Feed-through fly supplements such as Solitude IGR or Simplifly reduce the number of flies present on a farm. The trouble with these supplements is they have to be fed to every horse on the property and if there are horses nearby on surrounding properties, they should also be on it. It has to be a collective effort from the horse owners in the area.

Fly predators are one type of bug that I really like. These little bugs are so useful in reducing the fly population. Most struggles with fly control stem from damp organic material being left unattended. Damp organic material such as wet shavings, poop bits, and old hay and grain that is swept out of the barn but left at the end of the aisle is the fly’s favorite breeding grounds. Simply raking up debris will help reduce the fly population. For more tips and tricks about fly control, give me a call, I have all kinds of suggestions up my sleeve.

Three hundred sixty-five days a year, mosquitos are present. Unlike flies, there’s not a lot that can be done to reduce the number of mosquitos. However, getting rid of stagnant water is definitely useful. More importantly is making sure your horse is protected against mosquito-borne illnesses such as eastern and western encephalitis and west nile virus. These illnesses are life-threatening. Having your horse properly vaccinated is extremely important for prevention. This means having your veterinarian vaccinate your horse with properly stored vaccines at least twice a year. Did you know that if a box of vaccines is left out on the loading dock at your feed store, they might not be effective? And there’s no way to tell. Vaccines have to be kept at a very specific temperature, which your veterinarian knows, but the guy at the feed store might not. An ounce of prevention is worth a pound of cure.

Now, who do I talk to about these darn caterpillars? I swear I can’t get any rest without one of those things falling on me. Most of the time I wouldn’t care about the caterpillars, but recently the ones I have been encountering have been extra spicy. Have you noticed the ones with all the hairs poking up? Those are the spiciest of all.

Springhill Equine Veterinary Clinic

Caterpillars usually aren’t much of a nuisance to horses, but these hairy ones certainly can be. I’ve seen horses stick their nose in their feed buckets take a bite of feed and then run away and refuse to go back to it. I always like to inspect things, so be sure to check your horse’s feed and water buckets for these pesky critters. And use caution when removing them to avoid getting stung yourself!


The rain is coming. We might need a little bit of rain right now but halfway into summer, I can already hear the complaints about the rain. With rain comes a myriad of feet problems. From abscess to mushy foot to thrush. Wetness can cause your horse to come up lame at just the wrong time. Planning to go to a show? Trust me, your horse is probably going to get an abscess or develop mushy foot and be foot sore. I’ve seen it a million times.

Prevention is key. Have your farrier out on a regular schedule, usually every 4-6 weeks. Apply topical hoof care as directed by your veterinarian and farrier. And do not allow your horse to stand in mud, muck, and water all day long. This will damage your horse’s feet, and while I love seeing you all, I really do, I hate hearing that your horse’s feet hurt.

With rain and wetness comes the dreaded rain rot. No, rain rot isn’t a fungus, it’s a bacteria that infects your horse’s hair follicles and causes that nasty, greasy, gunk on their back and legs. Making sure your horse has ample time to dry after a wet spell, reducing hair length, and frequent bathing with CK shampoo will help reduce the occurrence and severity of rain rot. My docs know all the best products to combat rain-rot. Just call them, they won’t steer you wrong.

It’s not all bad

Summer isn’t all bad! The days are longer, which means you get more time with your horses, and who doesn’t love that? If you want to have a long, enjoyable summer of time in the saddle with your horse, prevention is key. Regular veterinary exams and being prepared before summer hits are essential to both your happiness as well as your horse’s happiness and comfort.

Until next week,


P.S. Want more? Check out my YouTube Channel! I’ve got seminars on rain rot, foot care, flies, and a lot of other topics. I’ve got how-to videos on all kinds of things. I mean, who takes care of you better than this cat? You can show me some love by subscribing to my blog, or my YouTube Channel, or my Facebook page, or to the Podcast that the humans do. I even have an Instagram and a Tik-Tok, if you can believe that. Just click on any of those blue words to go check it out.


Tuesdays with Tony is the official blog of Tony the Clinic Cat at Springhill Equine Veterinary Clinic in Newberry, Florida. If you liked this blog, please subscribe below, and share it with your friends on social media! For more information, please call us at (352) 472-1620, visit our website at, or follow us on Facebook!

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Electrolytes and Horses

Electrolytes and Horses

Tuesdays with Tony

As I was lying in the middle of the driveway yesterday, I realized it was a bit warm. Humidity wasn’t too bad though, but that can only mean one thing: Summer is coming. With summer comes sweat, for horses and humans. Cats simply will not lower themselves to something as banal as sweating. Sweating is tough on a critter! I found out just how tough while researching electrolytes and horses.


That’s a lot of water!


At full exertion, horses can produce close to 4 gallons of sweat per hour! Yeah, I’m never going to exercise that much. That means they have to replace all that water when they’re done exercising. More importantly, it means a horse exercising gets dehydrated really, really quickly. That horse losing 4 gallons of water is at critical dehydration levels at the end of the hour. Let’s be honest, most of your horses (and humans) don’t exercise to max levels, but even sub-max is a decent amount of fluid loss. Why are we discussing this? Make sure your horse has access to PLENTY of water before, and after exercise. If you’re exercising for longer than 30-45 minutes you should even have water available during exercise. Another fun fact, horses (and humans) sweat even more in hot, humid weather. It’s never hot and humid in Florida, right? (should be read in an extreme level of cat-sarcasm tone).

Springhill Equine Veterinary Clinic

More than just water


That sweat is more than just sweat. It contains a bunch (and I do mean a bunch) of electrolytes. For horses, they lose electrolytes in this order: Chloride> Sodium> Potassium> Calcium> Magnesium. Why does that matter? It means any electrolyte supplement should replace them in that order. In other words, check the label on your supplement. It also matters because those electrolytes are really important for things to happen the way they should in the body. One thing they do is make sure the gut moves the way it’s supposed to. You horse people don’t like colics, right? Electrolyte levels get whacked, you’ve got a colic. Electrolytes make sure all kinds of muscle contractions happen correctly, besides just the gut ones. The heart beat and muscles depend on proper electrolytes, as well. Basically, they’re pretty darn important to life.


I see sugar


Know what else horses use a lot of when they exercise? Sugar. That has to get replaced back into the muscles. This is what horses are surprisingly not great at. If you run a marathon (I don’t know why you would, but if you did), you could replace the energy stores in your muscles in about 12-24 hours. A horse doing equivalent exercise takes 48-72 hours to do the same thing! Crazy! Most of this energy is replaced by the normal process of eating hay and grain, but some of it is replaced by the sugar you see in electrolyte supplements. That sugar also helps the GI tract absorb the electrolytes. I think we can all agree a lot of sugar is bad, but a little bit is critical for exercise recovery.


What does all this really mean?


It means, if your horse is a pasture potato, having a salt block available and feeding a good quality hay and concentrate will meet all their needs. If your horse has to work for a living (this means physical labor as opposed to being in a supervisory role like myself), you will need an electrolyte plan.


On a day-to-day basis, a salt block along with a good diet is probably adequate, unless your horse is in hardcore training. When work gets stepped up though, it’s time to add in additional electrolytes about an hour before the hard work starts. Even better, but this can be nearly impossible with horses, add electrolytes to about a gallon of water, and have your horse drink them. Yeah, I know, you can lead them to water, and all that, but a bit of training before big events will help your horse learn this valuable skill. Make sure your horse has plain water available as well.

Springhill Equine Veterinary Clinic

After work, be sure to offer electrolyte water again, or add to the next concentrate meal. This will help your horse replenish those valuable electrolytes as fast as they can.


The Perfect Electrolyte


There are approximately 1 bajillion different ones on the market. Look for ingredients in the order horses lose electrolytes, with one exception: chloride. Chloride tags along for the ride with all the others, so sort of by default, you’ll get lots of that.


Bottom line: look for Sodium (often listed as salt), potassium, calcium, and magnesium in the ingredients. There will be sugar in there too, and that’s okay! A little bit of sugar helps the gut absorb those electrolytes. BUT (and it’s a big BUT) sugar should NOT be the first ingredient on the list. It should be around 3-4 down on the list, and will likely come before magnesium. Once you have the right ingredients in the right order, pick the one your horse likes. That’s the really hard part.


Electrolytes are way more complicated than I ever dreamed! Speaking of dreaming, I’m going back to holding the chair in the back office down. You be a good human and scroll down a little further to subscribe to my blog. You’ll get it a day earlier than everyone else, and that will make your Monday a little cheerier.


Until next week,



P.S. I know that I’m the resident celebrity around here, but my docs are starting to get worldwide attention with the podcast they do. Horse people all over Canada, UK, Europe, and Australia are listening, as well as people in all 50 states here in the US. Have you checked it out yet? It’s called Straight from the Horse Doctor’s Mouth. You can click on that link and find out for yourself what all the fuss is about!

Tuesdays with Tony is the official blog of Tony the Clinic Cat at Springhill Equine Veterinary Clinic in Newberry, Florida. If you liked this blog, please subscribe below, and share it with your friends on social media! For more information, please call us at (352) 472-1620, visit our website at, or follow us on Facebook!

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Tuesdays with Tony – Anhidrosis

Tuesdays with Tony – Anhidrosis

I know my adoring fans are used to hearing me talk about blood, manure, urine, and infections. But today I am going to discuss one of the lesser blogged about bodily fluids of horses: sweat. I often see horses come through the clinic that are as sweaty as Steven Avery in Ken Kratz’s fake murder narrative (yes, I watched a lot of Netflix over Memorial Day Weekend). Sometimes I hear owners complain about their sweaty equid, questioning whether he could perhaps be sweating too much? The answer is a resounding NO! Remember folks, if you are a horse, sweating is definitely a good thing!

Horses need to sweat to cool off (another bad design in my estimation). We cats, being superior and well, clean, never sweat. We simply pant if we get overheated, or preferably just lay in the air conditioning all day. Where horses run into trouble is when their sweating mechanisms fail. This usually occurs due to chronic over-stimulation of sweat glands in warmer climates (i.e. Florida). Stress is also thought to play a role, but the source of stress can be as simple as hot weather! Ironic, right? Hot weather causes horses to stress out which makes them stop sweating which makes them even hotter. NOT the smartest species, obviously.

If you have a horse with anhidrosis, the technical term for non-sweating, you probably already know it. Look for signs like dry skin after a hard ride, sweating in patches instead of all over, increased breathing rate, and acting slow or lethargic in hot weather. If you suspect your horse may be a non-sweater, give our docs a call so they can check him out. Anhidrosis can lead to overheating. A temperature over 102.5 is always abnormal, and once it gets much higher horses are at risk of heatstroke and thermal damage. Yikes!

So, what can you do if your horse becomes a non-sweater or partial non-sweater? Most importantly, cool them off! This should go without saying, but if your horse is unable to sweat, you probably shouldn’t ride him for an hour outside at 2pm in July in Florida. Even a cat knows that. Try to ride in the early mornings or late evenings during the summer months, and if your horse begins to get overheated, cool him off as soon as possible with a bath, fans, shade, and cool water to drink.

There are several supplements available to treat anhidrosis as well, such as One AC, Platinum Refresh, and beer (yes, the alcoholic kind). Talk to the docs for their recommendation on what would be best for your horse. Hopefully horses will someday see the wisdom in my ways and learn to pant to cool off. Until then remember, sweat may be gross but it is more crucial than evidence in the Making A Murderer trial! Sorry, the Netflix…

Until next week!


2013-10-31 17.24.06

Tuesdays with Tony – Summertime!

Tuesdays with Tony – Summertime!

Summertime, and the livin’ is easy (if you’re a cat)!  I do love summer.  I lounge around in the A/C, sleep on the porch bench in the shade, work on my tan in the parking lot.  It’s a good time.  Of course, life is always good when you are a cat.  Now if you are a horse it’s a whole different story.  I hear horses have to do this thing called sweating.  It sounds dreadful.  Not only do they get hot and stinky, it happens because they are working for you humans.

Sweating is one of the reasons horses are amazing athletes.  Let me be clear here, cats are better, but horses are still pretty good.  Sweating comes at a price though.  Sweating causes a profound loss of electrolytes and water.  Horses have to have a way to replace those losses or trouble comes fast.  Horse sweat is different than human sweat in a few ways.  First, it has a different electrolyte make up.  Horse sweat is made up of potassium, sodium, and chloride, in that order.  Human sweat is sodium, potassium, chloride.  Small amounts of calcium and magnesium are also present in sweat.  This means electrolyte supplements for horses need higher potassium concentrations than those for humans.  It also means that while Gatorade tastes delicious, it is not an appropriate electrolyte replacement for horses.

Next, have you ever wondered why your horse lathers when he sweats, but you don’t? That is because horses have a protein called latherin in their sweat.  I sometimes marvel at human scientists.  You named it latherin.  Seriously, couldn’t come up with something more original than latherin? Turns out latherin has a very important job.  This protein helps the sweat move from the skin, though the hair, and out to the surface where it can evaporate as quickly as possible.  Since humans aren’t lucky enough to have fur, they don’t need latherin.

Because horses have to be weird, some of them decide to stop sweating.  This is known as anhidrosis.  Anhidrosis happens when heat and humidity hits a certain level.  Here in Florida we experience lots of heat and lots of humidity.  So if it’s July, you are out riding, and your horse isn’t sweating,  get them back to the barn and hose them down quickly.  The brilliant human scientists aren’t sure why this happens but there are several products out there that help some horses.  I would recommend talking with our Docs about treatment options.  Management is really important with these guys.  They adopt a cat-like attitude about life.  They want to be in front of fans at all times and only work in the coolest parts of the day.  Unlike yours truly, frequent hose downs will help them stay cool.

While I have no desire to experience this sweating thing myself, it is pretty amazing from a purely cat-curiosity standpoint.  And as a cat, I know quite a bit about curiosity. To help your horse deal with all that sweat, be sure they are drinking and replacing electrolytes. Know what is normal for your horse and be ready to stop exercising if something seems off.  And most important, if in doubt, take a nap on the porch.

Tony at Springhill Equine resting after managing the equine veterinarians.