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The “Hot” Horse, Health, and Cooling Them Down

The ‘hot’ horse.  Covered in sweat often for no reason.  Irritated, agitated, poor stamina, poor recovery, and often followed with an unruly behavior pattern.  Some can even hinge on the edge of becoming anhidrosis cases or become more prone to E.I.P.H. . We’ve all seen them but they come in a variety of shapes and sizes.  In many cases, there are also health issues or even lameness conditions that accompany this ailment.  So, why does this happen and is there anything that can be done to help the average horse afflicted with excess internal heat?

Hot and Sweaty Horse
Hot and Sweaty Horse

Increased body heat is a normal part of physiology and a natural response to excessive environmental temperatures or exercise.  The body temperature goes up and then in most normal cases, sweating occurs to help release the heat and cool the body.  This is all to be expected in certain situations such as training or when the outside temperature is hot enough, but some horses appear to be more sensitive.  In those horses, just standing out in the sun, even on a mild day, can result in sweating which can be profuse at times.  In other cases, with just a light workout, heavy sweat begins to pour down their body and foam accumulates between the legs.

This isn’t just a sign that maybe they are not in top condition or health, but can be a sign that they are just more sensitive to the heat.  In reality, many of these horses already have an increased internal body temperature due to other factors or just their personality or constitution.  If the horse has more internal body heat, then the outside temperature can add to the equation, as can exercise.  Adding more heat to an already hot situation, which then results in sweating.  This additional heat adds more stress to the body, creating irritability and anxiety, which then results in the behavior patterns that can be seen.  This can also lead to more health ailments as well, as more stress upon that animal impacts overall health.  Thus, not uncommon to see ulcers in these patients, certain lameness conditions, and even a predisposition to development of EIPH or exercise induced pulmonary hemorrhage.

What’s the deal and how can you cool them down??

Predisposing Factors and Contributors

In some horses, they just tend to run a little more hot than others.  This is the difference between personality and body types.  We all tend to see a breed, such as the Thoroughbred, as being more ‘hot’ in nature, which is true as compared to some other breeds.  Although this hot aspect is true of that breed, it really is artificially created by our interaction, as explained later.  In fact, all breeds can be hot natured, if the circumstances are right, but this does not mean that inherently they are a ‘hot’ horse or breed.

In most of the horses that I personally interact with, this hot nature is secondary to either a dietary issue, stress, or a lameness or health problem.  Thus, when this is remedied, the internal heat begins to reside and the behavior pattern is eliminated.  Along with that, the health conditions of concern are often more readily managed.

Predisposing factors to heat susceptibility:

  • Diet
  • Stress
  • Concurrent health or lameness condition

The diet is the number one influence upon creating a hot natured horse.  In most cases, the horse is being fed too high of a volume of grain products, whether if that is a commercial grain or a whole-grain blend.  Either can, in high enough volume, lead to gastrointestinal disturbances, inflammation, and an increased rate of internal heat production secondary to the fermentation process.  Grains are heating, period, and a horse was never intended to be fed the grains in the volumes that we currently feed them at.  As a by-product of this excess grain administration, not only in the body temperature elevated, but behavior patterns will change, and ulcers are more prominent.

The second major influence is stress upon the horse, which can be due to environmental issues, feed related problems, herd dynamics, excessive training or lack of exercise, or due to a health or lameness concern.  Stress alters the physiology of the body, and when in the acute phases, it will raise the body temperature and open the pores.  This is why many of us sweat when we are anxious or nervous.  It is the same with horses.  The body temperature elevates and when combined with a high outside temperature or exercise, it makes the body more prone or likely to sweat.  Again, this elevation in body temperature will impact behavior as well, creating more stress, which through the cascade of physiological events will make the horse more prone to ulcers and other health concerns.

The third major influence is an associated health or lameness condition.  In the case of an infection, the body temperature will rise naturally, which then can be compounded by a high outside temperature.  This is to be expected.  However, in the case of a chronic lameness, such as laminitis, a tendon condition, or even thin soles, if the condition is painful enough, it will create stress for that animal.  Pain results often in contracted musculature, which raises the body temperature.  The pain itself, just through the stress response, will also elevated metabolic function and the body temperature.

Health Consequences of a Hot Body Temperature

These consequences should be obvious and go without saying, but plainly speaking, a higher than normal body temperature is not a good thing.  These consequences are made worse when put to the test with exercise or exposed to a high environmental temperature.

These consequences include:

  1. Dehydration
  2. Electrolyte imbalance
  3. Poor recovery
  4. Poor stamina
  5. Impaired cardiac function and circulation
  6. Impaired digestive function
  7. Organ damage
  8. Increased stress / ulcers
  9. Worsening of current health or lameness conditions
  10. Increased risk of developing anhidrosis
  11. Increased risk of developing EIPH
  12. Death

One of the biggest factors with all of the above mentioned conditions in the horse is oxidative stress damage which is inflicted by the heat and internal stress within the body.  A horse may start the day, after a period of fasting and rest, with a high antioxidant load within their body, but as they are exposed to heat, exercise and stress, those levels may quickly fall.  This is critical, mainly due to the fact that as those levels fall, the body is not as protected against free radicals.  As a result, the horse becomes quickly susceptible to oxidative stress damage.  

The bottom line is that yes, some horses do run a little more hot than others as a part of their normal personality, but in cases where excessive heat becomes a problem, intervention is warranted.

Intervention to Aid the Hot-Natured Horse

In all cases, the first thing that needs to be done is to properly evaluate the horse with a good physical exam, preferably by a qualified veterinarian.  The purpose here is to make sure there are no concurrent health problems, such as an infection, dehydration, or organ compromise.  It is also important to rule out any major lameness conditions, in which most cases they are obvious in these circumstances.  A horse with an acute overheating condition, heat exhaustion, can be cooled down with water, but not cold water!  Use more tepid or lukewarm water, so you don’t create a shock like response.  Do it gently and not abruptly.

After the ‘all clear’ is given by your veterinarian, ruling out any major medical or lameness concerns, the next item on the list to evaluate is your horse’s diet.  In most cases, excessive grain is being fed to the horse, which is creating the problems outlined above.  In some cases, even a small amount of grain being fed can be enough to trigger problems in that horse.  This is often due to gastrointestinal disturbances present, within the microbiome, which are present and are not capable of properly handling the grain.  This is often the case with horses that tend to go ‘hot’ when fed alfalfa, which is a common complaint among horse owners.  In fact, alfalfa is a cooling food, energy wise, and has been used for centuries as a rejuvenating ingredient.  If a horse tends to become hot when fed alfalfa, it is often not the food source, but more indicates an inability of the digestive tract in that animal to handle the nutritious food and high protein content.  In many of these cases, the horse is also being fed a significant amount of grain and is enduring high stress loads due to training or being stalled too much.  All of that stress, food stress too, equates to an upset digestive tract.  When the digestive tract is not working properly, bad things can happen, impacting not only proper food digestion, but inflammation and even body temperature.

The next area to address is the stress response, which can be either primary or secondary.  In some cases, such as with diet problems, the stress response can be created secondarily.  In most of the other cases, it is primary and due to environmental factors such as too much stalling, too much training, herd dynamics, or otherwise.  This stress response can also be associated with a current health or lameness condition, such as confining a horse to a stall for a tendon or foot condition.  In almost every case when dealing with a hot natured horse, stress is a major factor.  The question is what is contributing to it and how are you, as the owner, going to handle it?

If the diet and the stress response have been addressed, but yet, you still have a hot horse that is overly anxious and prone to sweating, there is more that can be done!

Managing stress can be a challenge and even when all factors are corrected, some still struggle with the concept, which may be part of their personality.  In those cases, I personally like to take advantage of adaptogens, which are herbs proven to help mitigate the stress response, quieting it down and helping to restore balance to the body and mind.  There are two formulas that I will use, dependent on the needs of the patient.

  • Cur-OST EQ Adapt & Calm – a single adaptogen formula utilizing Ashwaghanda to help settle the stress response and quiet the mind.
  • Cur-OST EQ Adapt & Recover – a multiple adaptogen formula which includes Ashwaghanda, but also takes advantage of several others including Eleutherococcus, Schisandra, Hawthorn, and Pomegranate.  These help to smooth that stress response but have additional health benefits in regards to antioxidant provision and supporting a healthy cardiovascular response and circulation.

The body temperature can also be influenced by what the horse eats, as noted with the heating aspects of grains.  However, you can take this to the opposite extreme and take advantage of other foods to help cool the body down.  All foods have an energy to them, some hot, some cool or cold.  Watermelon is a favorite with horses and can be fed in limited quantities to help cool the body.  All green foods are cooling as well, which includes things like spinach, alfalfa, and other forage types.  Dandelion is also another cooling food with tremendous medicinal properties.  Many fruits are also cooling, which include strawberries and blueberries. Although these foods are very beneficial not only to body temperature and health benefits, you must monitor the quantity that is fed.  If too much of a cooling food is fed, it can upset the digestive tract as well!

One new formula that we have been using in OTTB’s in our facility is our Cur-OST EQ Cool Down.  This formula utilizes:

  • Artichoke extract – known for its cooling effect on the body, reducer of inflammation, and provider of many nutritional and detoxifying benefits.
  • Blueberry extract – known for its ability to cool the body, but also packs a punch for cellular health due to inherent antioxidant properties, anthocyanins, ability to mitigate inflammation, and even impact blood sugar and insulin response.
  • Aloe extract – also known for the ability to soothe and cool the body, but provides a moisturizing effect to many tissues including the digestive tract and stomach.

The Cur-OST EQ Cool Down is a unique and very powerful formula!  It helps to cool the body down internally, support digestive health with prebiotic benefits, and provide tremendous antioxidant support.  

Our Approach to the Hot Horse

In our facility, our main focus is on the off-track Thoroughbred and many of them come in to our program as hot as a fire cracker!  In addition, most have ongoing lameness concerns associated with a tendon and foot problems such as thin soles or poor hoof quality.  The first step in our program is to modify their diet, which often improves them almost overnight.  The second step is to impact the digestive function and support it, in which case we use the Cur-OST EQ Tri-GUT.  The third step is altering that stress response using adaptogen herbs, Cur-OST EQ Adapt & Recover.  In most cases, they are doing quite well with this program in the first week.  In others, they remain a little hot, more inclined to stress and sweating.  In those, the addition of the Cur-OST EQ Cool Down has provided remarkable benefits, not just from a heat perspective, but they also appear to recover better after workouts and many have benefits in overall healing.  This effect is likely due to the antioxidant support that the formula provides, aiding cellular function.  This could prove beneficial to those horses afflicted with EIPH or anhidrosis conditions. 

In the end, if your horse tends to run a little hot, it should make you look a little closer.  There could be a bigger problem present than you realize and it could be compounding other health, training, or behavioral issues.

Take a closer look into that ‘hot’ natured horse and with some proper support, they could turn out to be a diamond in the rough!


Author: Tom Schell, D.V.M, CVCH, CHN

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