⚠ CAUTION: Extreme Heat Advisory! ⚠
Warnings like these mean summer is in full swing. Day after day of excessive heat can stress out any horse owner. Read along to understand the "why" behind their challenges and how we can help them thrive in the heat!
Unlike humans who can sweat readily and dissipate heat through most of their body surface, horses face a physiological challenge in staying cool. Their thick musculature and insulating fat layer make it harder for them to shed internal heat. Sweating is their primary cooling mechanism, but in high humidity environments, sweat evaporation – which is key for heat loss – is significantly reduced.
The horse's digestive system adds another layer of complexity. The fermentation of fiber-rich forages like hay generates significant internal heat. This is beneficial in winter, aiding in thermoregulation, but becomes a burden in hot weather.
Despite these challenges, there are ways to support your horse during the summer through management and (you guessed it) nutrition!
It seems counterintuitive that horses would drink less as it gets hotter, but it’s a very common (and serious) problem.
Make sure you can see to the bottom of those water troughs and buckets.
If you’ve ever had a horse spread and stomp on their fresh hay, then you know first-hand how sensitive they are to tastes and smell. This applies to their water as well. Varying pH levels and water hardness (mineral levels) can dramatically impact palatability.
If it’s tough to know whether you’re looking at a layer of algae/dirt/hay versus the bottom of the tank, or your horse simply stopped drinking from that trough, it’s time to clean and refill it.
While some still recommend this and many horses will drink it just fine, all too often we see horses refuse fresh water with any additives. Any salty-tasting product will change the taste of water and reduce palatability.
We don’t want anything to stop your horse from drinking. So, we recommend providing daily electrolytes in your horse’s feed or through a paste. The added benefit is you also know how much they’re actually getting.
The average horse needs 5-7 gallons of water per day during normal, cool-weather days. For some horses, this can increase as much as 4x when it gets hot - without exercise! To maintain hydration levels and normal bodily functions, be sure to compensate for loss through sweat during high temps and exercise.
If your horse is out with their friends, we recommend having multiple water sources. Especially in high heats, it’s not uncommon for dominant horses to start resource-guarding and prevent more passive horses from drinking.
This stress can be from heat alone, travel or any kind of environmental changes. Keep a special eye on your worrywarts. Consider ways to better control their environment with fans, extra rinse-offs during peak heat hours, or making them hang out only in shaded areas.
For every 1000 lbs, a horse at maintenance in average temperatures, should drink around 6 gallons of water per day.
Exercise and heat dramatically increases the amount of water your horse needs.
Studies have shown that an average horse, NOT in work, drank 5-7 gallons per day. However, under high temperatures, this same horse’s water intake could be more than 20 gallons per day! That’s a huge increase.
This doesn’t even factor in exercise. In one study, horses exercised at high temperatures and high humidity increased their water intake 79% for four hours.
It isn’t safe to give a hot horse cold water to drink.
It’s commonly believed that it isn’t safe to give a hot horse cold water to drink. Some social posts and blogs recommend that it’s better to give them lukewarm water when they’re hot.
This is not true.
A recent study found water temperature (ambient vs. chilled) to have no effect on horses health or consumption during hot summer weather.
In cooler weather, the average 1100lb horse should be consuming around 2 tablespoons of salt per day.
Standard table salt is all you need. We recommend free access to a loose white salt, or salt added to feed daily in addition to a white salt block. Horses do not have a rough tongue like cattle, so consumption when using salt blocks only is less than ideal.
The goal is to provide about 12 grams of sodium per day to the average adult horse, but these requirements increase with exercise and hotter temperatures.
Sodium is an essential mineral and electrolyte, not only responsible for critical life functions, but sodium is also what creates your horse’s desire to drink.
Simply put, when there’s more sodium in the bloodstream, a horse’s brain tells them to drink more water. If it’s low, this impulse will not happen.
Salt intake from loose salt was observed to be higher than from salt blocks, due to the ease of consumption
1. Preventing dehydration is key to keeping your horse drinking and healthy during these hot months. Sodium is also the electrolyte lost the most through sweat, which makes it extremely difficult to help a horse recover from dehydration and sodium-loss.
2. Provide access to a salt block 24/7 and monitor how much your horse is eating to ensure your horse is consuming a minimum of 2 tablesoons per day.
3. Expect that free choice salt will not be enough during the the hottest parts of the summer. Horses rarely spend enough time with salt blocks (or loose salt) to meet increased requirements.
4. White salt blocks generally only contain sodium, and will not cover all lost essential minerals. Sodium and many other major electrolytes are lost much faster during high temperatures, through sweat, including potassium and chloride.
Making sure that your horse is drinking plenty of water should be your top priority to prevent dehydration and reduce health risks in high temperatures. However, it’s not the only critical factor. Your horse must also be able to replenish their electrolytes.
Electrolytes are lost through sweat. Whether your horses are just turned out or being exercised, they will need a well-balanced electrolyte, in addition to salt.
Studies have shown that, even when turned out with little activity, horses in hot weather can lose about 4 liters of sweat per hour (a little over 1 gallon).
More dramatically, if your horse is a big sweater or exercised, research shows that they can lose up to 16 liters of sweat in one hour.
That’s 4.25 gallons!
In cooler temperatures, with light to moderate exercise, most horses will generally get enough electrolytes through a balanced diet. This would include a balanced, fortified feed, quality hay, free access to salt and clean water.
Too much salt makes feed less palatable and horses won’t eat it. Most feeds are fairly low in sodium, and should be paired with white salt. Individual needs for electrolytes can vary widely from horse to horse. So, it’s much more practical to supplement when needed.
There are many ways wild horses get salt and electrolytes, through a lot of effort and many miles traveled. These horses will consume loose salt and minerals that build up on surfaces near sources of salt water, as well as through certain plants.
Hot months and strenuous exercise take a larger toll on the well-being of wild horses.
In the past, guidance was more often a reaction, with recommendations to give electrolytes following exercise or noticeable symptoms of dehydration.
However, current research supports a much more proactive approach. One study even traced electrolytes through horses’ blood streams. These researchers found that when horses were given electrolytes before exercise (compared to water alone) they lost less water and fewer electrolytes.
Horses also exhibited better stamina during exercise, as well as post-workout recovery. when provided electrolytes prior to exercise.
Three electrolytes lost the most through sweat. Look for a supplement that, at a minimum, includes:
If you have a performance horse or a serious sweater, research shows that extra magnesium and calcium can help with muscle recovery following exerise or heat stress. While calcium and magnesium are lost in much smaller amounts during sweating and often covered through a balanced diet, the added benefits can help some horses navigate the summer heat much easier.
While some added sugar will be okay for some horses, too much will dilute the amount of included electrolytes. Additionally, concentrations of sugar can cause gastric distress.
Many supplements will add large amounts of sugar (glucose), to make the product more palatable, so be sure to check labels for added sugar levels.
