Horses have difficulty dealing with dry heat, but they have even more difficulty coping with the combination of heat and humidity. Part of the reason is that horses can cool off in dry heat through the evaporation of sweat, but in humid weather sweat just serves to insulate your horse, making him even hotter. Plus, some horses have trouble sweating (anhydrosis) during humid weather, which means they have no way to cool off at all.
Is Your Horse Too Hot and Humid?
Luckily, there are simple ways that you can help your horse stay cool during hot humid weather. During these weather conditions, the first thing to do is to calculate the temperature-humidity index (THI): simply add the air temperature (in degrees Fahrenheit) to the percentage of humidity. For instance, if the air temperature is 80 degrees Fahrenheit and the humidity is 60 percent, the THI is 140. When the THI reaches about 150, your horse may have difficulty cooling off. At a THI of 180, you should not work your horse and you should take active steps to keep him cool.
Another method to check whether your horse is getting too hot during humid weather is to take his temperature. A horse's normal temperature range is between 99.5 and 100.5 degrees Fahrenheit, and can reach 103 and 104 degrees during workouts. If your horse's temperature reaches 105, he is danger of being overheated and can suffer chronic or permanent damage. Above 105 degrees, your horse will be suffering from heatstroke and will need immediate veterinary attention.
5 Ways to Keep Your Horse Cool in Heat and Humidity
Good horse health care during hot humid weather is neither complicated nor difficult. You just need to be proactive. Here are 5 steps you can take to keep your horse cool and comfortable.
1. Offer Plenty of Cool Water
Like people, most horses prefer to drink cool tasty water on hot humid days. For a horse that means having access to plenty of cool (shaded) water in deep buckets or troughs. In hot weather many horses want to drink deeply. Drinking plenty of cool water will help your horse stay cool. A horse at rest will drink 10 gallons or more per day, while a horse in work can drink twice as much. Avoid automatic waterers, which only allow horses to sip rather than gulp water. Plus, water from these automatic devices tends to taste like chlorine, which many horses dislike.
2. Provide Well-Ventilated Shade
Most horses can cope with hot humid weather in their natural environment, but stalled horses can often become overheated due to poor ventilation. To keep these horses cool, provide ventilation with strong fans. Adding misters that spray droplets of water can also keep confined horses cool. For pastured horses, offer well-ventilated run-in sheds if trees are not available for shade.
3. Cool Your Horse Before and After Workouts
Horses in training should be kept as cool as possible before, during, and after workouts. Before starting a training session, you may want to hose down your horse with cool water. Keep training sessions short and to-the-point, as horses worked at higher intensity over a short period are less likely to overheat than horses worked at low intensity over a long period. Finally, wash your horse down after his workout. Be sure to scrape off excess water after his bath since water can act as an insulator if left on his skin. Don't bathe horses who have trouble sweating (anhydrosis). Instead, sponge these horses with air-temperature water mixed with a liniment like Sore No More. This practice also helps horses who are prone to heat rashes.
4. Provide the Right Horse Feed
Don't feed a lot of hay during hot humid weather since the digestive process can make your horse feel even hotter. Instead, consider cutting back on grass hay and adding a flake of alfalfa. In addition, you can keep your horse's gut healthy and functioning with probiotics such as Acidophilus and Bifidus from Simplexity Health, or Pro-Bi. Offer daily electrolytes in the morning feed if your horse is in work. Finally, consider adding cooling foods such as blue-green algae, apples, citrus foods, barley grass, fresh peppermint, lemon balm, or cilantro.
5. Consider Your Horse's Fitness and Environment
Horses who are fit and well-conditioned usually adapt to hot humid weather more easily than horses who are out of shape. In addition, horses who live in constantly warm climates are also more adaptable to this kind of weather than horses who live in climates with extreme seasonal changes. Take these factors into consideration when deciding how much heat and humidity your horse can stand before his health is adversely affected.
Unless otherwise attributed, all material is written and edited by Madalyn Ward, DVM. Copyright (c) 2011 HolisticHorsekeeping.com and Madalyn Ward, DVM. All rights reserved.
Holistic Horse magazine is your guide to natural horse health. www.holistichorse.com