Observation

What you see. The starting point for addressing any equine health related issue is your observation.

YOU ARE OBSERVING

Sweating Excessively, or Inappropriately

Summary

SUMMARY
Like humans, horses sweat to dissipate heat. Horses sweat heavily during very hot, humid conditions and when they have been exercised intensely, especially when they are unfit. This is normal. Horses also sweat when they have a high fever, or are in pain or distress. Sweating that is out of proportion to the weather or the work, or that happens at rest, is a sign that something else is going on, and pain is one of the most common reasons. A horse sweating at rest in a cool barn should be assumed to be in pain or seriously ill until proven otherwise.
The loss of fluids and electrolytes from excessive sweating can itself result in dehydration, which can cause worsening of systemic illness and can lead to further problems such as muscle cramping, "thumps" (a hiccup-like spasm of the diaphragm), poor performance, and impaction colic.
A thick, white, foamy type of sweat, often referred to as "lather" or "soap," is the excretion of fluids, electrolytes, and proteins. Horses will often perspire in this manner if overexerted (exercised beyond their fitness level) and/or stressed. Lather between the hind legs or under the reins during light work in a horse that is otherwise fit and calm is worth noting.
Sweating can also be localized to one area of the body rather than all over. Patchy or one-sided sweating (for example on one side of the face or neck, or in a strip along the body) usually points to a problem with the nerves that control the sweat glands, not to heat or exertion. Older horses with a long, curly coat that fails to shed and who sweat in patches may have a hormonal disorder of the pituitary gland (PPID, or Cushing's disease). Horses that sweat less than expected, or not at all, in the heat have the opposite problem (anhidrosis), which is a separate observation in this guide.

Code Red

Call Your Vet Immediately, Even Outside Business Hours
- If the results of the Whole Horse Exam (WHE) indicate fever (Temp>101F/38.3C), or heart rate greater than 48 BPM that persists an hour after recovery from exercise.
- If this is not associated with any recent exercise.
Code Yellow

Contact Your Vet at Your Convenience for an Appointment
- If this is something you notice under saddle but the horse seems well otherwise.
- If the results of the Whole Horse Exam (WHE) indicate fever (Temp>101F/38.3C), or heart rate greater than 48 BPM that persists an hour after recovery from exercise.

You also might be observing

Very Common

Less Common

Rare

Pulse or Heart Beat Irregular, Arrhythmia

more observations

your role

What To Do

If your horse seems to be sweating inappropriately, you can begin gathering important information to discuss your concerns with your vet. Assess your horse's general health using the Whole Horse Exam (WHE). Look for other signs of illness or injury that might underlie the sweating. Pay attention to drinking and eating habits and hydration. Take some time to notice when sweating occurs. Is it associated with exercise or hot weather, or does it occur at odd times, seemingly independent of exercise or temperature? Does the horse sweat all over or only in specific localized areas?
• First decide whether this is an emergency. Take a heart rate, respiratory rate, and rectal temperature. A sweating horse that is also showing signs of colic, is trembling or stiff, has a resting heart rate over 60, or a temperature over 104 F needs a vet now. Call immediately.
• If your horse is not in obvious distress, begin gathering important information to discuss your concerns with your vet. Assess your horse's general health using the Whole Horse Exam (WHE). Look for other signs of illness or injury that might underlie the sweating: attitude, appetite, gum color, gut sounds, manure output, lameness, muscle stiffness, or a hard, swollen muscle group.
• Pay attention to drinking and eating habits and hydration. Check the gums for moisture and capillary refill time, and do a skin pinch on the neck. Note how much water the horse is drinking and whether manure is normal or dry and hard.
• Take some time to notice when sweating occurs. Is it associated with exercise or hot weather, or does it occur at odd times, seemingly independent of exercise or temperature? Does it happen at night? After feeding? When the horse is stalled versus turned out? Write down the times and conditions.
• Note where the horse sweats. All over, or only in specific localized areas? Is it symmetrical (both sides the same), or only on one side? Is the pattern the same each time? Take photos.
• Note what the sweat looks like: thin and watery, or thick, white, and lathered.
• If the sweating is exercise related, take the heart rate immediately after intense exercise, and again 10 minutes later. The heart rate should have dropped to a maximum of 60 BPM at 10 minutes post-exercise. A horse that stays above 60 at 10 minutes, or that is still sweating heavily 30 minutes after stopping, is either overexerted for its fitness level, overheated, or has an underlying problem.
• If the horse is overheated after work (hot to the touch, breathing hard, heart rate slow to recover), get it into shade or a breeze, hose or sponge continuously with cool water over the large muscles and the big vessels of the neck and inside the legs, scrape and repeat, and offer water. Do not stop cooling early because you were told cold water causes cramps; it does not.
• Consider their performance and conditioning generally. Has it changed? Is the horse tiring sooner, sweating sooner, or taking longer to recover than it did a few months ago?
• If the horse seems to be sweating inappropriately under saddle, consider whether they are fit enough for their level of exertion. Also consider heat and humidity, the weight of tack and rider, the horse's body condition, whether the horse has a heavy coat for the season, and whether the horse is anxious or in pain under saddle (back, saddle fit, mouth, or lameness). A horse that lathers during light work when it did not before should be examined.
• Review the horse's diet, supplements, and medications. Excess grain, changes in feed, or a new supplement can matter. Some medications and sedatives cause sweating.
• If your horse has a long, curly coat, sheds late, drinks and urinates more than usual, or has had laminitis, tell your vet. These point toward PPID.
• Share all of your findings and concerns with your vet. All of this is important information that may help your vet in determining the underlying cause and potential solutions.

What Not To Do

• Do not assume a horse sweating at rest is "just hot." Sweating at rest without a clear reason is a sign of pain or illness until proven otherwise.
• Do not continue to ride or work a horse that is sweating out of proportion to the work, lathered, or not recovering. Stop and assess.
• Do not withhold water from a hot, sweaty horse. The old advice to keep water away from a hot horse is wrong. Offer water freely.
• Do not stop cooling a hot horse early. Continuous cool-water hosing does not cause muscle cramps or founder.
• Do not give bute or Banamine to a sweating horse without talking to your vet. Pain medication can mask the signs your vet needs to see, and giving these to a dehydrated horse increases the risk of kidney damage.
• Do not give large amounts of electrolyte paste to a horse that is not drinking. Electrolytes without water can make dehydration worse.
• Do not ignore patchy or one-sided sweating just because the horse seems otherwise fine. It is usually a nerve problem and deserves an examination.

Skills you may need

Procedures that you may need to perform on your horse.

Very Common

Less Common

Stimulate Thirst

more skills

your vet's role

• Your vet first determines whether the sweating is a normal response to heat or work, or a sign of pain, fever, or disease. The history you gathered (when, where on the body, what the sweat looks like, how the horse recovers) is a large part of that.
• In addition to routine examination, your vet will look closely for the causes of pain and distress that most often produce sweating: colic, tying-up (exertional rhabdomyolysis), laminitis, a fracture or severe lameness, and fever from infection.
• Blood work can be very useful in better understanding electrolyte balance and hydration, and can also reveal muscle damage (muscle enzymes CK and AST), infection or inflammation, and kidney function. If PPID is suspected, a specific hormone test (ACTH) is run.
• For sweating that is localized or one-sided, your vet performs a neurologic examination to determine whether nerve damage is present and where it is, and looks for the cause (injury, infection, a mass, or an injection site in the neck).
• For sweating that is exercise related, your vet may evaluate the heart and lungs during and after exercise, check for airway problems, and assess fitness, diet, and electrolyte supplementation. A horse that recovers poorly from exercise may need a more detailed workup of the heart or respiratory system.
• Treatment depends entirely on the cause. For a normal horse that is simply overexerted or overheated, the answer is cooling, rehydration, electrolytes, and a fitness program. For pain, fever, or disease, your vet treats the underlying condition.

Questions Your Vet Might Ask: