Walking past the stables one afternoon, I noticed that Missy, one of our older mares, was lying down in her stable, looking quite unhappy. Without even waiting to check for heave lines on her sides, I know that she’s got colic. The cause? Because she’s an old horse, she doesn’t drink enough water.
You’d think that a horse would know how much water to drink, but it’s not that simple. And, getting a horse to drink when it doesn’t want to is an almost impossible feat.
So how much water does a horse need to drink in a day to stay hydrated? The average horse requires 5-10 gallons of fresh drinking water per day to remain hydrated. Where your horse will be in the 5-10 gallon spectrum depends on their age, breed, level of work, and weather.
Each horse requires their unique water intake, but a pinch test will tell you whether your horse is dehydrated or not. When a horse dehydrates, it is awful for its health. In some cases, dehydration can lead to the horse’s death.
Most horse owners are careful to monitor how much food their horse eats in a day but are often less cautious about water consumption. After all, how do you check how much water your horse has drunk for the day? This is almost impossible if your horse shares their paddock with other horses or animals that share its water container or trough.
If your horse is stabled at night, you may have a clearer indication of their nightly water consumption. Yet, not all horses drink an appropriate amount of water at night. Some horses are picky about drinking from a water bucket or a trough. They may prefer to drink from their stable bucket (seeming to drink a lot for the night) or like to drink out in their paddock and not in the stable (which may falsely convince you they are not drinking enough water).
The best is to look at the factors that could influence your horse’s daily water consumption and learn to monitor for signs of dehydration in your horse.
Factors Influencing a Horse’s Water Consumption
Several factors influence a horse’s daily water consumption. While you can’t control all of them, you can take note and help your horse drink more if needed.
Weather Affects Thirst
The weather has a significant impact on your horse’s water intake. On cold days, your horse will drink less water. That’s because they sweat and lose less water through physical activity. Warm days have the opposite effect. Sweaty horses are more thirsty, drinking more water.
When water is too cold or hot, horses are less inclined to drink it. A horse prefers water that is 45-65 ℉. In winter, this can be a problem if your horse’s water trough freezes. A horse can easily colic from icy water (understanding horse colic). They may also refuse to drink freezing cold water. Even warmer water higher than 65 ℉ may be unpalatable to your horse, causing them to reject the water.
Severe wind can also cause a horse to drink less water, but it can pull water from their bodies. They may stand with their tail to the wind. If their water becomes muddy or dirty with flying debris like sand, leaves, or other particles, they will drink less. I always use the rule that if I don’t want to drink out of my horse’s trough, I can’t expect them to drink from it either.
Age Decreases Drinking
Young horses are naturally quite attuned to drinking. They easily shift from mother’s milk to water, but older horses seem less inclined to drink enough. With age, horses suffer physical decline. One of the things that decline first is their teeth which lowers the roughage they eat.
This means older horses are less motivated to drink water because hay makes horses thirsty.
My young horse loves taking her hay and soaking it, and drinking a hay-water slop. But, my older mare will eat her hay delicately and only drink when she is really thirsty. This demonstrates how older horses often have a lower water intake than younger ones do.
As a result of age-related wear and tear, older horses often have compromised digestive tracts. This makes them more vulnerable to dehydration. Since they don’t drink as much water as younger horses, older horses often suffer more acutely the effects of being without water.
Horse Breeds Have Individual Water Needs
Different breeds of horses tend to have their own water requirements. Some horses, like Arabian horses, will require less water. That’s because of their lighter weight. Heavier horses need more water daily.
Therefore, a Shire or a Clydesdale will need much more drinking water than a Welsh cob would.
Level of Work Can Increase Water Intake
A horse that is peacefully grazing all day long will probably require far less than a horse that does a lot of work each day. Endurance horses need much more water while they are in training than non-active horses.
Physical activity induces sweating, which means your horse is busy dehydrating. (Find out how to tell when sweating becomes dangerous for your horse) When a horse is physically active, it will also have a faster digestive system. This means they will require more water to keep up with their nutritional needs.
Electrolyte Balance Helps With Water Retention
Any human athlete will tell you that exercise strips the body of water. It also removes valuable electrolytes and minerals from the body. When electrolyte levels drop, muscles begin cramping.
The worst part about electrolyte loss is that thirst stops, even though you really should drink more water. The same thing happens to horses.
Horses also experience mineral and electrolyte loss when they sweat a lot from exercise or heat. This results in an upset of their salt balance. As a result, when the horse should be drinking more water, they consume less because they don’t feel thirsty.
To counter this, knowledgeable horse owners place salt licks in their horses’ paddocks and stables. This helps the horse become thirsty again, and they will drink more water. If you choose to add a salt lick to your horse’s paddock or stable, take care only to add a suitable and safe one for horses.
Don’t ever use mineral or salt licks for other animals. Cattle licks contain urea, which is harmful to horses and can lead to kidney failure. I also recommend avoiding molasses-based licks as these are sweet and may cause your horse to eat more of the lick than their body needs (which can damage their kidneys).
Time of Day Impacts Water Needs
All too often, I see horses in their paddocks at noon with no water. If your horse doesn’t have access to a self-filling water trough or an ample water supply, check on their water at least three times during the day. This will ensure your horse always has access to water.
There will be times of the day when your horse needs more water, such as noon or late afternoon. Be sure they have access to fresh water at ALL times. Never assume your horse doesn’t need more water, even if it has gulped down 10 gallons recently. A medical condition and specific instructions from a vet are an exception.
Forage vs. Hay Impacts Water Needs
When your horse is eating natural grazing, they will be ingesting some moisture with the grass and legume sap that they eat. Hay, on the other hand, is a much drier feed.
A horse that stands in a paddock with short grazing and a hay net to munch on will require more water. Natural forage is juicier, while hay is drier, so be sure to give your horse access to water and a salt lick if they are on hay 24/7.
Specific Medical Needs
Individual horses may have specific needs for more water. For example, a mare that is lactating and nursing her foal will also require much more water. She will be dehydrating much quicker while she nurses and produces milk. Pregnant mares will also need more water as both she and the growing foal need it.
But, other specific health conditions may mean your horse needs extra water. Be sure to follow your vet’s recommendations if that comes up.
Signs to Check If A Horse Is Dehydrated
If you suspect your horse is dehydrated, you need to check them to decide how dehydrated they are and if you need a vet to come and administer treatment. Dehydration is not always evident by how much or little your horse has sweated or if they are breathing fast or not. Instead, you can carefully check for the following signs in your horse that they are dehydrated.
Pinch or Snap Test
When your horse is dehydrated, it will lose water from its skin first, which is why the snap test is so accurate. It’s pretty easy to administer:
With the horse standing with its neck straight, take a soft pinch grip on the skin of its neck. Pinch the skin together, hold it for a second or two, then release and watch the site where you pinched. If the skin snaps back into place, your horse is not dehydrated. If you release the pinch only to have the folded skin show for several seconds, then your horse is dehydrated.
Mucus Membranes Sheen
You can also check the mucus membranes. They are found inside the mouth and the eyes. A badly dehydrated horse will start to have a dry mouth, and their lips will hang limply or stick to their mouth.
If you press on their gums and it stays white for more than 2 seconds, your horse is dehydrated. They will have dry and red eyes, and you will quickly notice the “light go out” as their eyes lose sheen from drying out.
Lack of Appetite
A dehydrated horse will have no appetite. Since its mouth is dry, it won’t want to eat either. Instead of grazing, it will simply stand listlessly in its paddock. If you offer your horse concentrated or sweet feed, it may show no interest or may nibble at the food with little natural appetite.
Dry Stool Quality
If the dehydration is long-term, you will notice your horse’s stool becomes dry, and they may struggle to pass stool. The ball-shapes of the fecal matter may also be dried out as soon as your horse has a bowel movement. Natural horse stool is usually softballs that are slightly shiny.
Dark Color of Urine
An extremely dehydrated horse will not urinate much, though there may be a drippy discharge from a mare if she is severely dehydrated. If your horse is still passing stale, you may find their urine is dark brownish-yellow, which indicates the imbalance of electrolytes to water.
When dehydration is severe, your horse may become disoriented. They may walk into things. Their gait may be stumbly. Or, they may stand still with their head hanging low. These all point to a complete drop in energy levels and listlessness.
Blood Pressure and Other Vital Signs
Having assisted several vets with severely dehydrated horses, I know that one of the top signs (and problems) with a dehydrated horse is their loss of blood pressure. This makes it hard to find a vein for intravenous injection or to insert an IV or drip.
You will also notice a drop in heart rate, and respiration will soon become a threat, and your horse may gasp often. If you see these signs in your horse, you need to get a vet out ASAP!
10 Steps to Take If Your Horse is Dehydrated
If you suspect your horse is dehydrated, you can take the following steps to begin remedying the situation while assessing how severely dehydrated your horse is.
1. Free Access vs. Withholding Water
I have come across a few horse owners who insist that they encourage the horse to drink by withholding water. Please don’t believe this for a second. Horses need ad-lib or free access to water, all day and night long. Even if your horse tends to urinate a lot during the night, you should still give them as much water as they need. The one exception is if they have a medically diagnosed condition and you’ve got different instructions from your vet.
Ensure your horse has access to at least 10 gallons of water per night. You can also try out different water containers as some horses will not drink out of a metal container, while others refuse to drink from plastic.
2. Check Water Frequently
I like to draw a measuring line on my horse’s water container. This helps me check how much water they have drunk during the night in their stable or during the day in camp. If I notice they haven’t drunk as much water as is typical for them, I check them with a snap test and assess their vital signs.
That said, there are also nights when I’ve seen my youngster sleeping like a log for a good 4-5 hours! Not much drinking or eating is happening then, so I’m not at all surprised to find a full water bucket in the morning.
3. Mix Water Into Feed
If your horse is not drinking enough water or if you have already begun to notice dry stool and colicky behavior, you may need to force your horse to get more fluids in gently. Adding more water to their daily feed is an excellent way to do this.
You can mix your horse’s ration of concentrate or sweet feed with enough water to almost be soupy. Most horses will happily slurp this up, getting in a good couple of ounces in water too.
4. Add Salt to Feed
You can also add salt to your horse’s feed. Adding in as much as two tablespoons of agricultural salt or pink Himalayan salt to your horse’s feed will help your horse become more thirsty. Initially, you may want to introduce the salt gradually. I like to start with no more than a teaspoon of salt at a time.
5. Soak Beet Pulp
Another great way to help your horse hydrate is to add a couple of handfuls of beet pulp to your horse’s feed. This is then soaked in at least a gallon of water and then fed to your horse. If you use warm water to soak the pulp, wait for it to cool down before feeding.
Don’t be frightened by the volume of the food once the beet has expanded, and while it may weigh more than the recommended feed weight per meal, it is mostly water, so you can still feed it to your horse in one meal. To be safe, weigh the dry beet pulp and the sweet feed before adding in the water. The dry weight shouldn’t exceed 4.5 pounds per meal.
6. Alternate Water With Fruit Juice
If your horse is stubborn about drinking their water and the usual tricks haven’t helped, you can also feed them some watered-down apple juice. This can entice your horse to drink more water. Plus, adding fruit sugar can also benefit a dehydrated horse.
On the topic of sweet things, I have also seen the effectiveness of “sweetwater.” This is when you take a 5-10 gallon bucket of water and add in a good dollop of molasses. The water will have a typical molasses smell and taste, which will help your horse drink much more willingly.
With a colicky horse, you may choose to offer your horse sweetwater as this will help the horse drink more water. Be sure to have both sweetwater and plain fresh water in the stable or paddock for your horse.
Like a kid who eats too many sweets and is then thirsty, your horse will want to drink some freshwater too once they have drunk some of the molasses water.
8. Rule out Other Conditions
If your horse has become dehydrated, there may often be a different reason for its loss of water. Illness, trauma, and even stress may cause a horse to dehydrate. Your horse may be sharing a paddock with other horses that are aggressive and won’t allow your horse to drink.
This could mean your horse will be dehydrated. Offer your horse water and check for signs of agitation—it may be as simple as changing your horse into a different paddock to solve this dehydration issue.
9. Call a Vet to Administer IV Hydration With a Drip
Should your horse begin to display the signs of dehydration above, including dull and lifeless eyes, lethargy, lack of appetite, or fever, be sure to call the vet immediately! Administering an IV drip to hydrate your horse may be required to save their life if they are beyond the point of normal recovery.
Situations That Should Involve Water Caution
While your horse should have water at all times of the day, there are a few rare times when you should not give your horse water, and you should actually remove the water from their stable.
The Horse Is Hot
If you have just worked your horse or had a long ride, you should hand-walk your horse to cool down. This will ensure your horse can drink its water without choking or having an adverse reaction.
A hot horse from work will have an elevated breathing rate and heart rate, which can cause them to have a heart attack if you let them drink too much water immediately.
When a horse is under anesthesia or sedation, it will be disoriented after the surgery or medical procedure. The horse may be so disoriented that it gulps the water, choking or suffering a blockage. This is why many vets or equine dentists recommend that you remove all water and hay for 3-4 hours while your horse wakes up.
Manage Medical Conditions
Some diseases such as Cushing’s disease and even equine metabolic syndrome (EMS) can lead to a horse drinking too much water. This will result in too much pressure on your horse’s body systems and kidneys.
If your horse has a medical condition that requires management, you should only give your horse water as needed and avoid free-choice water.
Water Is Contaminated
If you suspect the water your horse is about to drink is contaminated, you should prevent your horse from drinking it. Bacterial and parasitic infections can result from your horse drinking contaminated or polluted water. This is a necessary time to dehydrate your horse to prevent them from drinking toxic water.
Extreme cold is not favorable to your horse’s water consumption. Most natural places to drink, such as streams and rivers, are usually frozen. Your horse will get colic from trying to drink frozen water.
If you live in the colder northern States, and your horses have access to a barn or a shelter, you can provide them with heated water. This will ensure your horse can drink water at the recommended temperature range.
Frequently Asked Questions
Can my horse drink too much water?
Some medical diseases, such as Cushing’s disease, can cause your horse to drink too much water, and they may also drink more water at once than other horses do. A horse shouldn’t walk into their stable and drink a whole 10-gallon bucket of water unless they have been dehydrated or if the weather is sweltering. On a hot day, horses can sometimes drink as much as 15 gallons of water a day.
If your horse drinks large volumes of water in one session, you may have a case of polydipsia or excessive drinking, which will, in turn, cause polyuria or excessive urinating.
Does my horse need constant access to water?
Yes, your horse will require 24/7 access to water unless you have been advised to withhold water by your veterinarian or if your horse has just undergone a medical procedure that involves sedation or anesthesia. In that case, you should withhold water until they are fully awake and alert.
Can a horse go without water at night?
Horses can go possibly 48 hours without water, but not without physical damage from dehydration. Although going all night without access to water probably won’t kill your horse, do not withhold water from your horses at night. This can cause prolonged dehydration and affect their overall health.
What are the signs of dehydration?
Common signs of dehydration include a lack of skin elasticity. Check this with the snap test, listlessness, dry and red eyes, colic, and a lack of appetite.
If you suspect your horse has become dehydrated, you should take action quickly. Monitor it closely, and if the signs of dehydration don’t improve or if your horse won’t drink water or eat watered feed, you need to contact your vet immediately.
A dehydrated horse can die within two to three days. Often, owners only realize their horse is dehydrated after a day or two. This leaves precious little time to rehydrate your horse. The sooner you act, the sooner your horse will recover, and it could save their life.