Sweating It Out - Dehydration and Non-Sweating
Anewcomer to horses once asked me, "Do horses pant or sweat?" For one accustomed to horses, it is common knowledge that they sweat. It never crossed my mind that anyone would think otherwise. Yet why wouldn't they? Dogs pant; cats do too. Horses generally don't. I had never really thought about it until then. Horses do sweat. In fact, they sweat more than any other species.
Sweating is a cooling-down process. Sweat is moisture, and moisture evaporates. Evaporation is a cooling process; thus sweating is a cooling mechanism. When a horse moves or exercises, the muscles produce heat and the body sweats to maintain an even body temperature. This moisture output is not always visible; a horse does not have to be wet with sweat to be losing moisture. In a healthy horse, this cooling process operates all the time.
The efficiency of the sweating process depends on the moisture level in the external environment. If the humidity is high, evaporation is minimal, and the cooling process is less efficient. Humid days are not good work days. The horse will pour out more fluid in an attempt to keep the temperature balance, thus losing more sweat on hot, humid days. A few gallons can be lost in just one hour of hard work under such conditions, and the horse can easily dehydrate and overheat.
Dehydration results from fluid loss - from excessive sweating, diarrhea, or a loss of large amounts of urine. The reduced amount of tissue fluid leads to a reduced fluid content of the blood and can be disastrous. Heavy sweating not only causes a loss of fluid, but due to the higher mineral content in their sweat, horses lose nutrients too. Sweat contains blood salts. Blood salts are the trace elements sodium, potassium, calcium, magnesium, phosphorus and chloride. They are a conducting medium, known as electrolytes, or tissue salts. They facilitate the conduction of electrical charges throughout the body.
What is lost during sweating?
Gerald Wessner, VMD from Summerfield, Florida, explains, "When a horse sweats, he loses essential moisture and a lot of electrolytes including sodium, chloride, and potassium. The tissues dry out due to moisture loss. In addition to sweating, fluids are lost through the urine and the bowels. As a horse exercises, the manure can get very loose, and even more fluids are lost."
The signs of dehydration are sluggishness, a drawn or tucked appearance, dry, shrunken skin and a harsh appearance of the coat. The eyes may become sunken. Muscular weakness is apparent and there may be increased thirst. There is less urine output, the heart rate may increase, and blood pressure may fall. There is an easy test for dehydration: with your thumb and forefinger, grab up a piece of skin in an area such as the shoulder and release it. If the skin does not immediately slip back to its original flatness, the horse is dehydrated to some degree and needs adequate rehydration.
"Dehydration can affect any horse, but it is a major concern among some sports, such as endurance riding," says Dr. Wessner. "Race horses and even performance horses don't normally lose much sweat in the short time they race or perform, but endurance horses with miles and miles of steady work are more at risk."
By thinking and acting in advance, one can easily prevent dehydration. This is the most sensible approach, of course. Be sure your horse has access to fresh water at all times as well as free-choice salt (there are non-compressed natural salt chunks and loose salt granules available) and free-choice mineral sources. Make the most of shade and avoid exercising in hot, humid conditions. However, if you compete in hot conditions, then you need to train in the same conditions to accustom your horse to them. Proper conditioning by getting your horse fit over a reasonable amount of time is essential.
Electrolytes are commonly used in endurance horses and in other strenuous athletic competitors before, during, and after the competitions to keep the horses' hydration and trace mineral levels balanced. These are available in powder form, which can be added to water or feed, or in paste form, with various compositions. Excesses can be eliminated through urination.
According to Joyce Harman, DVM, MRCVS from Washington, Virginia, "Most horses don't need a whole lot of electrolytes. People pour electrolytes down their horses when the vast majority of them do not exercise enough to need electrolytes. If the horse is getting a free-choice source of minerals and salt, separately so that they can take salt if they need salt and minerals if they need minerals, that is usually adequate. However, endurance horses and the endurance athletes such as the upper level event horses are a different story," she says.
"In those cases, one of the best things to do is start using your electrolyte solutions or formulas the day before the ride, and even the day before you ship, because some of these horses arrive at the rides dehydrated. You have to have plenty of water available for them; you can't just give them some electrolytes, load them on the trailer, not give them water, and then expect them to arrive at the competition in good shape. Start using the electrolytes the night before while they have access to plenty of water."
Electrolyte products seem readily available, but some are better than others. What is lost is what needs to be replaced - water, and the proper nutrients. In fact, scraping and collecting the sweat and feeding it back to the horse with water was sometimes done before the era of prepared electrolyte formulations to replace what was lost. Flavorings may make electrolyte preparations palatable, but the nutrient content is what is important.
Dr. Harman advises, "Use an electrolyte formula that is not full of sugar. Most of the formulations on the market contain more sugar than effective electrolytes. There are a few on the market that are truly made for endurance horses and have been made with absorbable nutrients. Those would be the best ones to use."
Prone to dehydration
Some horses are more prone to dehydration than others, for various reasons. Dr. Harman explains, "There are horses who are not as well-conditioned as others. There are also horses that have heavy body types; they will sweat more on a hot humid day. The temperature and humidity are also factors; humid climates are more likely to cause metabolic stress because the sweat does not evaporate. That's how horses cool, and when the sweat's not evaporating, they can't cool very well. And they keep pouring out more sweat. In the dry climates, they can dehydrate as well; occasionally the sweat evaporates so fast that the horses will feel like they are cooling plenty and go too fast and too far."
She continues, "Some horses drink well when they've got strange water, some horses drink poorly." In endurance competition, travel to strange places with different water is commonplace. Horses that get stressed metabolically often don't drink enough water. In eventing, many people actually forcefully rehydrate the horses after cross country. They feel it is beneficial whether the horse is thirsty or not. Endurance competitions do not allow that and the horse must drink on its own. And there are horses that don't drink as well as they should."
If a horse seems prone to dehydration, homeopathy can be used to treat the horse constitutionally. Ideally the horse should be treated with a combination of homeopathy and nutrition. Dr. Harman says, "Some of these horses that are prone to dehydration because they are not drinking very well may not be really healthy horses. Maybe they're not eating as well as they should, or maybe they have some other problems like a skin disease or a respiratory condition, indicating that they are not really as healthy as they need to be. With good quality homeopathy, we correct the horse's chronic disease or lack of health. Then things like dehydration are going to be less of a problem as long as the horse is well fed and supplied with minerals and salt."
Excessive thirst or lack of thirst can be a sign of an underlying imbalance and a clue to homeopathic prescribing. Dr. Harman explains, "Some horses tend to drink more water and some tend to drink less, but if they are within a normal range, that would just be a characteristic of that horse's constitution, personality, or temperament. The horses that fall outside of that normal range, who drink excessively or not enough, are exhibiting symptoms of a problem. Once we recognize this, we then try to correct the problem with homeopathy."
What can one do if a horse dehydrates? Dr. Harman says, "Straightforward dehydration is treated with water; that's the bottom line. You have to increase the water intake. Very mild cases of dehydration are treated with water and potentially electrolytes, if the horse is willing to drink. Rest him until he has corrected his fluid balance, and offer him hay or grass during that time because they also contain electrolytes and quite a lot of potassium. Some of these horses also need calcium and that can be found in a very absorbable form in the good endurance electrolytes."
"In an acute situation of dehydration, like in an endurance ride, you'll need to have a vet involved. A horse, at that point, if he's truly dehydrated, is probably not going to be drinking on his own because he's just too sick. He will need either stomach tubing or intravenous fluids."
Homeopathy can be used as well, with the help of a homeopath. "When you're treating a horse that's got a serious case of dehydration, you really want to be working with a homeopath that can recognize all the symptoms of what needs to be treated. It is important to choose the correct remedy for the horse at the time, because he may have a gut that's partly shut down, a case of thumps [spasms of the diaphragm] or some other things that need to be addressed. Any of these can accompany dehydration."
China, or Cinchona officinalis, is a homeopathic remedy suggested in some texts for dehydration: for great weakness from loss of body fluids and for helping to restore strength and promote a return to normal physiological condition. Dr. Harman says, "China could be used, but it may or may not be the best remedy depending on the horse and all the symptoms. So it is not something that I would recommend people use in a potentially dehydrated horse without a good deal of knowledge. Rescue Remedy [see Flowers to the Rescue, Premier Issue, NHM], however, is appropriate and is really very safe," she points out.
"You must also make sure that the horse is getting adequate fluids," she stresses. "You can give a homeopathic remedy in a case of dehydration, or in a case where an animal's been really sick and has lost a lot of fluids, but if you are not replacing fluids as well, you are not going to fix the problem. You've got to supply the body with the nutrients it needs, and in this case it's water. If they're not drinking then you need some veterinary attention."
Overheating and dehydrating often go together, but horses can dehydrate without overheating. If a horse is overheated, external applications of cool water with brief, easy walks in between until his temperature stabilizes, are very helpful. Dr. Harman says, "You want to cool the jugular area particularly, and the legs, where the veins are close to the surface. The eventing people use a lot of ice, the endurance people use a lot of water."
Using ice in an application should not be continued for too long a period of time because it closes down the surface capillaries and then the slightly larger vessels. This slows circulation and therefore slows the ability to cool the blood, so it's best used in a five-minutes-on, ten-minutes-off regimen, because while it will tend to constrict blood vessels temporarily, the body will produce a "rebound" effect once the ice is removed, increasing the circulation to those tissues. This is also the appropriate technique to use in cases of swelling.
Dr. Harman cautions, "If the weather is cool, a horse can still dehydrate but you don't want to put water on him because he is already cool. With the endurance horses, if they're really not fit enough and if it's a cool day, or if the riders just go too fast, the horses can be dehydrated and not necessarily overheated. In the cooler weather, I see that a lot. People will be pouring cool water on the horse and he's practically shivering. When the air temperature is cool enough, overheating is not the problem."
What if they don't sweat?
There are times when a horse will lose the ability to sweat. Dr. Wessner explains, "A non-sweater is an animal that, due to different types of stresses, just shuts down and doesn't sweat. Non-sweaters easily overheat; they pant and are very uncomfortable. They may try to stay in the shade all the time, and are miserable especially when the weather exceeds a certain temperature. They can be fine up to a certain point, then one degree more shuts them down." There may also be diarrhea which is another attempt by the body to remove some of the heat contained in those fluids.
It's a life-threatening situation to be without a cooling mechanism; the ability to maintain a proper temperature balance is vital. How does this happen? Dr. Wessner explains, "It happens from a series of imbalances. In my opinion, it's caused by excessive vaccinations and excessive chemicals, either in the form of substances added to the feed or too many wormers, and it's a cumulative effect. We're dealing with many years of vaccine use, and each year it gets more intense. We're also dealing with third and fourth generation antibiotics. And we're dealing with very suppressive drugs such as Banamine, Bute, NSAIDs, and all the artificial hormones."
He continues, "Think of it: when a mare is bred, they usually use prostaglandins to make her ovulate. Let's say she gets in foal, which rarely happens on the first time, so if it's done a couple times she has a couple doses of Progesterone or prostaglandins or something. She's finally diagnosed in foal and they give her a rhinopneumonitis vaccine at 5, 7 and 9 months. The immature immune system is being bombarded by this vaccine (a herpes virus), then the mare foals. Chances are they put iodine on the foal's navel, probably give it an antibiotic, and a tetanus antitoxin shot right away. The mare probably gets something to help her clean out. At a couple months of age, they've already wormed the foal's mother. At 4 months or less they're worried about worming the baby; then they start the vaccine series on the baby. Then, if they're headed to any kind of sale, they intensify the vaccine use because they don't want them getting the snots, the cough, the two-year-old throat, things like that. Plus, they're wormed every other month so that they don't get any worms. So you can see that over five successive generations, let's say 25 years, look how many drugs are being put into these guys."
It's no wonder there is a series of imbalances, considering the stress we put on our horses with all these routine practices that are taken so lightly. We unknowingly bombard our horses with many harsh, unnatural substances that can have lasting, cumulative ill-effects.
According to Dr. Wessner, "Only horses that are susceptible to the problem end up with it, IF they are stressed enough. Stress comes in many forms - it can be a horse that's in a swamp or a horse that gets snake-bit. It can be too many chemicals, too many wormers, too many antibiotics, or too many vaccines, especially the combination vaccines." He points out, "Right now we have a horse that was vaccinated for EWT twice a year, Rabies once a year, and flu-rhino six or seven times a year. In addition, that horse was wormed six times with ivermectin, and one of those times he was also wormed with a double-dose of strongid. This horse is a big, gorgeous Thoroughbred that cannot get to the races even as a three-year-old, because he's so weak he just keeps falling apart in different areas. A horse with that kind of conformation that is so big, gorgeous, and well bred should not be falling apart; he should be racing. I blame that on the overuse of wormers and the overuse of vaccines, especially the combination vaccines. We are seeing more and more of this type of problem."
Help for non-sweaters
"With homeopathy," says Dr. Wessner, "we are turning horses like this around all the time. What we do, first of all, is get them on a natural-type diet which would include barley, oats, and corn. I try to counsel the owners to make them aware of the problems with the vaccinations and we switch to homeopathic vaccines [see Boosting Immunity: Nosodes, Vaccines, Health; Issues 1 and 2, NHM]. We try to reduce all other chemicals that are given to them, in any other form. Then we put them on homeopathic constitutional treatment. This means that I do a thorough exam, take a very detailed history, and talk to the owner at length about the horse's stall manners, vices, and pasture manners to know where to start," he says.
"We start with one remedy then wait until that remedy does its job, usually from about three to eight weeks. At that point, we reassess and go on to the next remedy. When we are dealing with homeopathy and holistic medicine, we're aware that everybody is born with a core of chronic disease, like a little baseball. As we experience different stresses throughout life - whether it be pregnancy, living in a swamp, being snake bit, too many vaccines, too many antibiotics, too many chemicals, or even sickness with a lot of antibiotics - they are all layered onto the individual. Remember we are dealing with third and fourth generation antibiotics now which are extremely powerful drugs. These suppress not only the production of the bacteria, they suppress the immune system as well."
Dr. Wessner continues, "So then we have these layers being built up, and each layer has a 'personality'. As we unlock that top layer with the first remedy, the next layer with its personality starts to come out and show itself. So we choose the remedy for that layer, give it, and wait. That remedy does its job and that layer disappears, and another one pops up. It's like peeling back the layers. Then we get down to, and identify, the core, and the chronic disease is basically pushed aside. At that point, theoretically, the animal can now withstand all the vaccines, and all the chemicals, because now he has some strength to his immune system in his body, where before that, he was vulnerable."
If your horse is unusually prone to the ill-effects of heat and humidity, or is a non-sweater, consider getting a constitutional case-taking from your homeopathic veterinarian. Problems such as these and others can be baffling and untreatable according to conventional medicine but homeopathy can help. The core problem and any underlying imbalances can be addressed and many conditions can be truly corrected.
Joyce Harman, DVM, MRCVS operates Harmany Equine Clinic, a holistic equine veterinary service in Washington, Virginia, where she offers homeopathy, acupuncture, chiropractic, nutrition and Chinese herbs. She has also been an active endurance judge and participant.
Gerald Wessner, VMD, operates the Holistic Veterinary Clinic in Summerfield, Florida where he offers homeopathy, acupuncture, and nutrition. His practice includes horses, especially race horses, and small animals. He also hosts a radio talk show on veterinary homeopathy Saturday mornings on central Florida's 720 AM.
Natural Horse Magazine thanks Dr. Gerald Wessner and Dr. Joyce Harman for their help in preparing this article.