Horses That Can’t Sweat (Anhidrosis)
By Dr. Lydia Gray on December 17, 2008 at 1:38 pm Diseases and Conditions, Seasonal Horse Care
What can you tell me about anhidrosis? I understand it has something to do with a horse not sweating properly, but I don’t understand why horses develop this problem. Also, I heard there’s a treatment for it but you have to start it BEFORE the horse actually stops sweating, which is different than most other treatments.
Anhidrosis is a frustrating condition because scientists still haven’t figured out exactly why horses gradually lose the ability to sweat. Based on numerous studies, experts think 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 receptors). Most recently, a team of researchers found evidence that sweat glands of horses with anhidrosis secrete chloride ions differently than other horses. Chloride is a component of normal sweat along with sodium, potassium, calcium, magnesium and other minerals (electrolytes).
The manufacturer of the most popular supplement for anhidrosis, One AC, offers another explanation (from the website):
“One AC is based on the theory of imbalance of dopamine to the noradrenaline/adrenaline complex. Dopamine is first used by the brain, then by the cardiovascular system and last by the sweating system. A reduction in dopamine below a certain level allows the well-known vasoconstrictive properties of the noradrenaline/adrenaline complex to predominate and reduce the blood carrying capacity of the peripheral vascular system to a minimum, thereby reducing the ability of the sweat glands to function properly.”
Because there are no prescription medications to prevent or treat anhidrosis, One AC is probably the supplement you are referring to, the one that should be started before the horse has a problem. According to the manufacturer, horses that have been diagnosed with anhidrosis should begin receiving One AC before the beginning of the hot season. In fact, some owners keep their nonsweating horses on One AC year-round and simply lower the dose during the cooler months. The manufacturer also suggests reducing strenuous training or work for a minimum of three weeks after first putting the horse on One AC for best results.
Because sweating is a horse’s primary means of cooling itself, horses that don’t sweat can become overheated and perform poorly or even collapse. Here are some additional tips to help keep horses cool:
• If you’re bringing a horse used to a cool, dry climate into a hot, humid one, 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 before the hot months. This way you won’t have to do distance riding or interval work in addition to regular schooling when it’s warmest.
• Work your horse during the coolest 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 as water as cold as he will tolerate! Upper level event horses are routinely sponged off with ice water until the water scraped off is the same temperature as the water going on.
• Provide cool air with good barn ventilation, fans (especially misting fans), and even air conditioning.
• Stimulate drinking and replenish the minerals lost in sweat with an electrolyte scientifically formulated specifically for horses.
• Look for and treat any underlying diseases, especially respiratory conditions, and reduce other sources of stress.
Horses that live in hot, humid climates are the ones that tend to develop anhidrosis, and for years it was thought that it was more common in horses that moved to these warmer regions from cool, dry climates. However, studies have shown that just as many horses that were born and raised where it’s hot and muggy lose the ability to sweat as those who move there. And no breed, sex, or gender is safe, as studies have shown any adult horse is just as likely as another to develop anhidrosis. The bottom line: all horses should be closely supervised and managed appropriately when heat and humidity are high. Horses with anhidrosis just need a bit more TLC.
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54 Comments
I am leasing a horse and I live in Houston, TX. Hot, Humid miserable weather in the summer, especially this year. My vet came to do a wellness check on this horse, a 14 year old gelding. When told that he had anhidrosis, she recommended not purchasing. Said I was in for lots of extra care, very limited output from the horse in this climate and since I didn’t have a barn only shade trees I didn’t have a good way to cool him.. I’m curious what your thoughts are.
Jim,
I live in Pilot Point TX and do hair testing on horses. I specialize in nonsweating horses. The cause is dietary and changes in diet can enable the horse to sweat normally. I have gotten every horse I have worked with sweating.
Susan Cook PhD toxicologist
susan how can I contact you?
Thanks,
Mike
Mike,
Please contact me if you are still having problems …just saw this today 2/25/12
You can contact me at cook.sek42@yahoo.com.
Susan Cook
My horse is in Tioga and she just started showing signs of anhydrosis. She is a 2-year old. Can you help me? She is a reiner and we haven’t been able to ride her since this started. We have no idea why it started. We are giving her a supplement that the vet gave us which may be helping a little, but she doesn’t like to eat it.
Hi Terry,
Wish I had seen this sooner …
Susan Cook
susan i met you years ago, am in aubrey. please contact me to get tox report done. thank you
Donna,
Just saw this today …2/25/12. Let me iknow if you are still having problems with your horse….
Susan
Susan Cook, PhD toxicologist
Please offer advice if you can. We have a Welsh pony (about 13 years old or so, and about 900 lbs.).
Last year is the first year he was unable to sweat, and it’s happening again this year. We stay with him all afternoon and early evening when the temp goes up. Its’ very hot and humid this year, as last year.
We use shower baths, and wet sheets on his back, and put him in a totally shaded corral during the hottest part of the day. He “woofies” I call it—blowing through his nostrils, panting, and very rapid heart rate. These methods bring it down, but not totally to normal, and he has to be monitored constantly.
Is there anything that can be done? I’m worried even about his life at this point.
We have found ONE AC and ordered it….hope it helps but we’ve read posts from some who say it does no good.
You mentioned diet. He is on Buckeye Supreme, as both of our horses have been for years, with only a little yellow corn feed added (i.e., Tuckers). I can’t imagine Buckeye hurting him.
Thanks so much for your input. How can we contact you?
Ann Foster
Ann,
Just found this today …contact me if you are still having problems. Unfortunately, most commercial feeds contain minerals and toxins that can be problems for some horses.
Susan Cook
Please contact me at cook.sek42@yahoo.com if you still need help.
Susan Cook PhD
Hi Susan, I have a 12 year old Training level event horse that has suddenly stopped sweating. I live in Indiana and it has been unusually hot and very humid the past 3 weeks. I am interested in doing the hair testing on him. Please let me know the basics of what you found (ie. high protein causes it, etc). Thanks! Liz
Hi Liz,
Please contact me if your horse is still having problems. I did not check this blog until today …
Susan
Did not realize my email address did not occur in the comment. It is cook.sek42@yahoo.com.
Susan Cook PhD
Susan,
I just purchased a 9 yr QH gelding and rode him for the first time today, he breathes very hard and sweats very little. I am in VA very hot & humid, he came from OH. What can I do to help him with this?
Shanda,
Please contact me if you still need help. Checked this blog for the first time today …
Susan cook
If you still need help please contact me cook.sek42@yahoo.com
Susan Cook PhD
please contact via email concerning a non sweating horse. what changes in diet should i do. i have her on One AC two scoops daily. no changes seen.
Linda,
Please contact me if you still need help.
Susan
Please email me or call me 727 422 9873
Jill,
Did not see this blog until today ….will phone you.
Susan Cook
Hello Susan,
I live in Florida. Recently my wife’s thoroughbred mare stopped sweating and has been panting heavily.I’m very interested in what diet changes or what type of diet do you recommend. Thank you
Hi there, hope you get this. How young can a horse be to develop this. We have a yearling we think may have it. She doesn’t sweat even trying to sweat her neck and nothing. She can go for a couple miles at a jog and still nothing. She is tough. Not very sensitive at all to halter, chain or nerve line. Only thing that bugs her is having her ears clipped. Any info would help please. Thank you. D
Hi Divina, thanks for your question. Anhidrosis has been diagnosed in horses of all ages, breeds, and types, and does not appear to be limited to certain age groups. Therefore if you suspect your filly may have this condition, our recommendation is to have your veterinarian examine her as soon as possible. Your vet will be able to recommend the best treatment, workload, and management for her. Best of luck!
Divina,
Just saw this today …. please let me know i you still need help.
Susan Cook
PLease contact me at cook.sek42@yahoo.com if you still need help.
Susan Cook PhD
Mrs Cook how can I talk to you about a horse im looking at to buy that doesnt sweat.
Thanks Jon
We have a TB mare (Naya, about 16 years old) that does not sweat.
Are you still doing the hair testing? If so, how much it would cost? We are in Roanoke, TX and we can bring her to Pilot Point pretty easily if you are still there.
Let me know whenever you have a chance.
Thank you,
Ignacio
214.762.2722
socas@aol.com
Jim,
Just found this on the SmartPak blog. If you are still having problems, please email me.
Susan Cook
Please contact me at cook.sek42@yahoo.com if you still need help.
Susan
If you purchsed this horse he can sweat normally with my protocol.
Please contact me at cook.sek42@yahoo.com.
Susan Cook PhD
Jim,
You can contact me at cook.sek42@yahoo.com if you still need help.
Susan Cook PhD
Jim,
Please contact me at cook.sek42@yahoo.com if you still need help ….
Susan Cook PhD
hello i have a horse named apollo and i live in florida and as we know is hot and muggy but he does not sweat at all but when im outside with him he acts just like a normal horse and when i ride he sweats alot…. any advice ???????
Kelsi,
Just saw this today …plese contact me if you need help ….
Susan Cook-
Please contact me at cook.sek42@yahoo.com if you still need help.
Susan Cook
I would also like Susan’s contact information. I have a 2 year old filly that is starting to show signs – she has not completely stopped sweating yet. I gave her a tube of electrolytes and put a mineral block in her feed bin yesterday, and I noticed she sweat more and cooled down easier after I rode her this morning. Any info is much appreciated….
Erin,
Saw your comment today …ws not checking this blog … let me know if you need help
Susan Cook
If you still need help please contact me cook.sek42@yahoo.com.
Susan Cook Phd
I have an 11 year old paint mare that just stopped sweating te last couple of days. I would like to get in touch with Susan. We also have another horse in our barn that hasn’t been sweating for about 6 weeks. He has been on beer and 1AC and they aren’t helping.
Thanks.
Eileen,
Please contact me if you still need help …did not check this blog …
Susan Cook
Eileen,
Please contact me if you still need assistance ,,,,did not check this blog
Susan Cook
Eileen,
If you still need help, please contact me at cook.sek42@yahoo.com
Susan Cook PhD
Hello Susan, I, like the others, have a 10 yr old gelding who is having great difficulty with this ungodly Texas heat this year. What dietary changes should I be making with my guy. He is a pleasure horse though I have quit riding him until I get him under control. Is it a low protein diet? No alfalfa hay, low protein grain ration? Any info you can give me will be greatly appreciated.
Susie
Susie,
Plese contact me if you still need help with your horse ….
Susan Cook
Susie,
Please contact me at cook.sek42@yahoo.com if you still need help.
Susan Cook PhD
I own a 5 year old QH Gelding who colicked and went toxic on me right before Memorial Day this year. He spent a week in the equine hospital and the vet said he should not have lived through it. The vet has no idea what caused him to colic, but what I noticed is he wasn’t sweating and I live in SC. I put him on One AC as well as Quench and Probios and he now sweats like he should and I haven’t had any problems with him colicking again. We have had heat indexes of 110 to 115 this summer. I know the One AC is working because he is sweating normally now.
Kimberly,
One AC does work on some horses. If your horse should stop sweating again, please contact me.
Susan Cook
Kimberly,
If you have problems again please contact me at cook.sek42@yahoo.com. In most horses anhydrosis is a nutritional problem ….it would not hurt to check him out …
Susan Cook PhD
I have been asked to assume responsibility for a 20 year old solid black miniature mare, who has been diagnosed with anhydrosis and can not sweat when the tempertaure gets above 90 degrees, I am disabled and on a fixed income and am wondering how to best accomplish this. I have several acres and a pond, but no barn or stalls. Does it take a lot of money to care for an animal like this? What is the easiest way to help her? I have no expierence with horses.
Hi Linda,
It does not take a lot of money to care for a pony with anhidrosis. It does cost a bit to find out why she is not sweating. Would the owners be willing to chip in on hair testing and my fee??? After that sho should be normal and your pasture sounds ilke a perfect spot as long as she has shade available.
Susan Cook
Dear Susan,
I just got some One AC today, but would also like to try to find food that has the right Chelates of iron, copper and whatever else my horse needs. Can I just get that food and try it, or do I need to do the hair testing? How much does the testing cost? Where can I get the food? Thanks.
Hi Kathleen,
Thought I had posted a reply but it evidently failed.
Please email at cook.sek42@yahoo.com for the information you need. There are several causes of anhidrosis so hairtesting is needed ….especially if OneAC does not get your horse sweating.
Susan