When the temperature drops, it’s easy to assume your horse’s hydration needs do too. After all, cooler weather means less sweating, less work, and no scorching summer sun. But in reality, horses are just as vulnerable to dehydration, especially during severe temperature swings. Understanding the role of electrolytes and hydration during the colder months is essential to maintaining your horse’s health through the winter.

Why Winter Dehydration Happens

In winter, horses often drink less water simply because it’s colder. Ice-cold water isn’t appealing, and when water sources partially freeze, access can be limited. Combine that with dry winter air, dusty hay, and the natural moisture loss through respiration, and your horse can easily end up mildly dehydrated — even if they’re not sweating heavily.

The biggest concern over winter dehydration is equine colic. Impaction colic is the most common in the setting of dehydration, and can lead to emergency vet calls, surgery, or worse, euthanasia. Gut motility is especially important in the colder months, and encouraging hydration helps maintain it.

The Role of Electrolytes in Hydration

Electrolytes are minerals, primarily sodium, chloride, potassium, calcium, and magnesium, that regulate fluid balance, muscle function, and nerve activity. In summer, we often focus on replenishing electrolytes lost through sweat. If your horse loses too much, it can lead to an electrolyte imbalance and lead to tremors, muscle cramping, or seizures, just like in humans. 

Electrolyte supplementation in the winter focuses less on mineral balance and replenishment and more on encouraging drinking behavior. Think about eating a salty meal, you’re more likely to drink a tall glass of water afterward because it creates thirst.

Providing adequate electrolytes in winter helps stimulate thirst and maintain the body’s fluid balance.

Key Electrolytes and Their Functions

• Sodium & Chloride (Salt): The most critical electrolytes. Sodium chloride drives thirst, encourages drinking, and maintains proper hydration.
• Potassium: Essential for muscle function and nerve impulses; commonly found in forage but can still need supplementation.
• Calcium & Magnesium: Support muscle contractions and nerve signaling; imbalances can contribute to muscle tightness or poor performance.

Encouraging Water Consumption in Cold Weather

One of the simplest ways to keep your horse hydrated is to make water more appealing. Here are some practical strategies:

Keep Water Warm

Research shows horses drink significantly more when water is between 45°F and 65°F (7°C–18°C). Use heated buckets, tank heaters, or insulated troughs to prevent freezing and maintain a comfortable temperature. Always check heaters for electrical safety and grounding to avoid shocking your horse.

Unfortunately, this isn’t a practical solution for many horse owners or barns, so we make sure there’s fresh water available after each meal, since this is when horses drink most of their water for the day. In the rare instances here in the Southeast when it drops below freezing, I’ll make sure ice is broken and removed from water troughs, and soak my horses’ feed in very warm water before serving it.

Offer Salt Freely

Salt is the most effective natural way to stimulate thirst. You can use bulk livestock salt, sea salt, table salt, or mineral salt. It’s helpful to provide:

• A loose salt source (plain white table or livestock salt) in addition to a salt or mineral block.
• One to two ounces of salt per day for an idle horse, and more for working horses or those sweating under blankets.

You can mix salt into feed or offer it free-choice. Horses often don’t consume enough from a block alone, especially in cold weather.

Flavor Water When Needed

If your horse is reluctant to drink, try flavoring their water with a splash of apple juice, molasses, a few drops of peppermint extract, or a small handful of soaked hay pellets. You may have to experiment to find something they like. 

I only tend to do this as a “treat” since my horses are kept in small herds, and flavoring a large shared water trough isn’t very sensible. If the weatherman is predicting a big swing, I’ll make a very soupy mash or mix warm water with my horse’s favorite flavoring in a 5-gallon water bucket. I aim to get them to drink one or two bucketfuls, so at least I know they’ve had that volume to drink, and I can sleep better at night.

Soak Their Feed

Adding water to feed is an excellent way to boost hydration, and I do it all winter. Some people opt to soak their hay, but I don’t have the setup or the patience for soaking hay, and I find that my horses get the most benefit from a mash.

My horses are fed a mix of grain and alfalfa pellets in winter, and these rations are at a decent enough volume that they can handle a respectable amount of warm water without turning into soup.

Some hiccups I’ve encountered with this method are when a horse is on a very small amount of feed, like a ration balancer, or if I add too much water and create a runny soup. Small amounts of feed aren’t able to hold enough water for effective hydration. If I create a soup, my horses end up tossing most of the water out with their muzzles to get to the good mush, defeating the whole purpose. 

When and How to Supplement Electrolytes in Winter

Electrolyte supplementation should be tailored to your horse’s activity level, diet, and environment. Consistent, low-level electrolyte support in cold months is best when they aren’t sweating excessively so as not to dehydrate them accidentally.

Light to Moderate Work

Horses in light training or regular turnout can typically meet most of their electrolyte needs through salt supplementation. Adding 1–2 tablespoons of salt daily to feed, plus free-choice access, is often sufficient.

Heavy Work

Horses that are exercised regularly may still sweat significantly during workouts. For these horses:

• Offer a balanced electrolyte supplement (powder, paste, or in water) several times per week.
• Choose products with sodium and chloride as the primary ingredients, not just sugars or fillers.
• Avoid giving electrolyte supplements in plain drinking water unless you also offer an unflavored water source — some horses will refuse treated water.

Common Myths About Winter Hydration

Myth 1: “Horses Don’t Need Electrolytes in Winter.”

False. While they may not lose as many electrolytes through sweat, horses still need them for normal body function and to maintain a healthy thirst response. Even mild deficiencies can lead to decreased drinking and digestive issues.

Myth 2: “Horses Get Enough Water from Snow.”

Also false. Snow is not a reliable water source — horses would need to eat massive amounts to meet their daily hydration needs, which would lower body temperature and increase energy demands. Always provide fresh, liquid water.

Myth 3: “Electrolytes Cause Dehydration.”

This myth likely stems from misuse. Electrolytes can draw water into the digestive tract, but when offered with free access to fresh water, they actually encourage water consumption. The key is balance and consistent access to clean water.

Winter Dehydration Can Be Sneaky

Winter dehydration is a hidden threat that can sneak up on even well-cared-for horses. By keeping water accessible, offering adequate salt and electrolytes, and monitoring your horse’s drinking habits, you can help prevent colic, muscle fatigue, and poor performance during the cold months.

Quick Winter Hydration Checklist

• Offer free-choice salt and mineral (loose or block form)
• Add 1–2 tablespoons daily to feed (I “salt to taste”)
• Soak feed mashes regularly or offer a warm “tea” periodically if your horse doesn’t eat enough for a true voluminous mash
• Watch for reduced manure moisture or urine output
• Use heated buckets or troughs to prevent freezing if you’re able
• Supplement electrolytes according to your horse’s workload
• Monitor for signs of dehydration or colic and consult your vet if needed

Proper hydration isn’t just a summer concern; it’s a year-round responsibility. By giving a little extra attention to water and electrolyte intake during winter, you’ll help your horse stay healthy, comfortable, and ready for whatever the season brings.