The summer months are the most anticipated, yet barely tolerated, months for most horse owners. We praise the longer days for more time at the barn, but we curse the heat that makes the middle portion of the day miserable for both human and horse. If you live in a portion of the country where humidity hits its peak and you learn more about corn sweat than you ever thought possible, it makes things feel even worse.
If you're miserable in the summer heat, what about your horse?
Think about it: We can escape to the indoors, where it's bug-free and has air conditioning. Your horse cannot.
Health Concerns in the Heat
Just like humans, horses can succumb to heat stress and heat exhaustion, as well as other health concerns that can become dangerous. However, according to a study by the University of Guelph, it only takes 17 minutes of moderately intense exercise in hot, humid weather to raise a horse's temperature to dangerous levels (from 98.6°F/37°C to as high as 109°F/43°C). This is 3 to 10 times faster than in humans.
This is because of two reasons. First, horses have a higher percentage of active muscle than humans. Second, while horses do tend to produce more sweat than humans, a far lesser amount of sweat evaporates, making their bodies less effective in cooling themselves down than a human's body, according to Professor Michael Lindinger.
Three big concerns for horse owners during a summer heat wave are dehydration, heat stress and heat stroke.
Dehydration Your horse can suffer from dehydration year-round, but it's more prevalent in the summer and winter. There can be multiple causes of dehydration, but the most frequent causes include lack of available water, stress and extended periods of travel. On a typical day, the average idle 1,100-pound horse will drink 6 to 10 gallons of water per day. However, in a hot environment, that amount of water needed can easily double or triple.
Some signs of dehydration in horses:
- Fatigue/less energy
- Gums are tacky to the touch
- Decreased appetite
- Skin does not flatten when pinched
- Colic
Heat Stress We discuss the perils of heat stress for humans in another blog, but it may surprise you that horses can succumb to heat stress faster than humans. Heat stress occurs when there is a breakdown in the way a horse’s body normally cools itself down (sweat cannot evaporate and allow for proper cooling).
Some signs of heat stress in horses:
- Excessive sweating, or lack of sweat
- Temperature of 102°F to 105°F
- High respiratory rate (flaring nostrils/rapid breathing, more than 10-12 breaths per minute)
- High heart rate that doesn’t improve with rest
- Skin feels hot to the touch
- Signs of dehydration (lethargy, skin stays together longer when pinched, pale/tacky mucous membranes, sunken eyes, etc.)
- Weakness/stumbling
Heat stress in horses can cause hypotension, colic and renal failure.
Heat Stroke If the heat stress is left untreated, and your horse's internal body temperature rises above 105°F, this can lead to heat stroke, which can be fatal.
Some signs of heat stroke in horses:
- Temperature above 105°F
- High respiratory rate and high heart rate continue
- Refusal to eat or work
- At worst, collapse and convulsing
Handling the Stress of the Heat
The most important thing you can do to combat heat stress or heat stroke is to know your horse. Know what his normal vitals (temperature, heart rate, respiratory rate) are so you can recognize that your horse is starting to struggle before things get too concerning. As soon as your horse is showing any of the symptoms, immediately end your riding session, seek shade and start to cool off your horse while someone contacts a veterinarian.
Cool off your horse quickly by hosing him down (or dumping buckets of water on him), starting at the legs and working your way over the entire body. According to the American Association of Equine Practitioners (AAEP), a 2020 study found that out of five methods tested, the quickest way to return to normal body temperature was to have the horse stand with continuous tap water application. Offer your horse small amounts of water to drink throughout this process. If your horse starts to exhibit signs of colic, tying up or his signs aren't improving, it's time to call the veterinarian. Your veterinarian may administer electrolyte fluids via IV or a stomach tube to help restore the horse’s internal balance of minerals lost in the horse's sweat.
Combat the Heat
The most important thing you can do to help combat any threat of heat stress with your horse, according to Dr. Lindinger, is to have your horse drink water with electrolytes. You can start slow with just a small amount of electrolyte solution added, then increase the amount throughout the days and weeks of summer.
While most equestrians will ride and train in the morning or evening, if you plan on doing some intense riding or competing at some point in the heat of the day, you need to acclimate your horse to the heat prior to attending the event. "You need to get horses used to being ridden in the heat and allow them to develop the full spectrum of beneficial adaptations that come with heat acclimation,” says Dr. Lindinger.
Utilize the shade to help stay cool. If you're able to ride or work in a shaded area, especially with a breeze or under fans, this will allow your horse (and you) to stay comfortable during your riding session. If your horse is starting to get hot, this is a warning to move to the shade and start to cool him off.
If you must haul your horse during the summer, try to avoid hauling in the heat of the day, especially if your trailer is completely enclosed (unlike a stock trailer with open slots along the sides). Open as many windows and vents as you can, safely, to allow airflow for your horse and do not cover your horse in a sheet or heavy shipping wraps or boots. (Unless you're able to utilize wraps like the Revive Tendon and Hock Wraps.)
If you turn your horse out during the day, offer plenty of options for shade and a large quantity of clean, cool water for him to drink. If you keep your horse inside, make sure your barn is well-ventilated to allow a breeze (or provide barn-safe fans) and access to cool, clean water.
Prepare for the Heat
In order to enjoy your summer riding safely, remember that preparation for the heat begins early. Horses that are fit and in shape can handle the stressors of summer heat better than overweight horses. The same goes for age—younger horses can handle the heat better than older horses. Early planning for a conditioning routine and utilizing cooler spaces to ride can help your horse be a bigger part of your summer.
