When temperatures start to get both warmer and more humid, the effectiveness of sweating to cool the body decreases. So, if your horse is working hard and it’s a hot, muggy summer day, the horse’s body will struggle to cool off. So, how do we keep our horses cool?
Let’s first consider the horse from a day-to-day perspective as it’s living in a pasture or stall. Make sure that your horse has access to fresh, clean water at all times. Horses can drink anywhere from 5 to 15 gallons of water a day, depending on the weather and if they have been exercised. In addition, make sure your horse’s diet is well-balanced and that they are getting enough salt in their diet. Two key electrolytes are sodium and chloride, and those are both found in salt. If your horse is on a forage-only diet, they should have access to a salt block or a mineral block. You can also top dress feed with loose salt; for a 1,100-pound horse, you would want to add 1 ounce or 2 tablespoons of salt per day. Talk with an equine nutritionist if you have concerns about the amount of salt in your horse’s diet. Make sure that your barns and trailers have good ventilation, whether it’s open windows or using fans. If your horse is outside, make sure they have access to shade somewhere in their pasture at all times of the day.
Exercising horses in hot environments
When exercising your horse in the summer, check the weather forecast. Consider not just the temperature but also humidity, wind, and whether it’s a sunny or a cloudy day. An 85°F day that is cloudy with some rain and wind will feel very different than an 85°F day that is muggy and sunny. Many weather apps on phones have a “real feel” forecast and that usually takes into consideration both the temperature and humidity. These apps often also include how cloudy and windy it is, which can all help to determine the thermal load that your horse may be experiencing. Remember that in very humid environments, sweating is less effective because it cannot evaporate as well. So your horse will be hotter, and extra care will need to be taken to manage your horse’s body temperature.
When exercising your horse, there are a number of things you can do to reduce the thermal load for your horse. Consider the time of day when you exercise your horse in the summer; morning is the coolest time of day, followed by the evening. The hottest time will generally be midday-late afternoon, so try to avoid exercising at that time. Consider reducing the distance or effort of the training session – perhaps do fewer/shorter jumps or ride for a shorter distance than you normally do. On very hot, humid days, you could even decide not to exercise your horse. Consider the horse’s fitness level, as an unfit horse will struggle more with the hotter temperatures than a horse that is in shape. Horses should be allowed to drink water before, during, and after exercise, particularly if the exercise is strenuous or long in duration. This will not increase the risk for colic, it is essential to keeping your horse hydrated.
After exercising your horse, there will be several signs to indicate that your horse needs to be cooled off quickly. Your horse will be sweaty, blood vessels will be prominently visible on the skin, the skin will be hot when touched, they may be blowing hard through their nostrils, and there may be behavioral changes (tired or unsteady on their feet). The normal body temperature of a horse is approximately 99 to 101°F. If a horse is experiencing heat stress (rectal temperature above 103°F, increased heart rate and respiratory rate, profusely sweating, exhaustion/lethargy), you need to rapidly cool the horse with water and contact your veterinarian.
How to cool off your horse
To rapidly cool off a horse, hose off the entire body for 5 to 15 minutes until symptoms subside. Thoroughly wet the entire body of the horse – do not focus on certain areas. There is no need to scrape water off the horse – just keep applying water! If you don’t have a hose nearby, use a sponge to liberally apply water all over the body or even dump buckets of water on your horse. As long as the water is cooler than the horse’s body, it will work.
There have been multiple research trials looking at the most effective way to cool a horse after exercise, and all have come to the same conclusion – continuous application of cool water for 5-15 minutes will lower the body temperature of the horse the quickest. It does not have to be ice water – water from a hose is perfectly fine. When water is being applied to the horse, conduction is utilized to remove sweat from the horse. Research has also shown that scraping the water will not improve the recovery of the horse – in fact, some studies have shown that it slows down the rate of recovery. The water on the horse is still cooler than the horse itself, so heat is still being pulled away from the horse. If you want to scrap your horse at the end before you put them in a stall, that is fine. But during the active cooldown, just keep applying water.
Even in warm temperatures, it is possible to enjoy the outdoors with your horse. Know the signs of when a horse is hot, and if you need to rapidly cool off your horse, continuously apply water over the entire body until symptoms subside. Be sure that your horse is well hydrated and has sufficient electrolytes in its diet. Contact your veterinarian if you suspect your horse is suffering from heat stress or heat stroke.
Danielle Smarsh is a Equine Extension Specialist and Associate Professor in Equine Science
