Keeping Horses Healthy In Hot Weather

Summertime can be known for record-breaking heatwaves. Being mindful and planning ahead can ease your horse's adjustment to warmer weather.

Here are some important tips to prevent heat-related problems in horses:

1. Know the signs of fatigue and overheating. These signs include:

• A high respiratory rate (>40 breaths per minute) that does not come down with 10 to 30 minutes of rest, changes in mental activity or decreased energy levels.
• Mucous membranes in the mouth become dry and lose their usual “slimy” feel.
• You may also notice a prolonged capillary refill time, indicating dehydration. To test, push on your horse’s gums. They should start out pink, then blanch to white after pressure, and return to pink in one to two seconds.
• Use a stethoscope, or put your ear on your horse’s flank, behind the ribs, to listen for gut sounds. Gurgling sounds are normal and good. Quiet gut sounds are a warning that your horse may be uncomfortable.

2. Keep your horse hydrated. Maintain hydration by allowing free access to water at all times. It is a myth that if a hot horse drinks water it will experience colic or other medical problems. If you think your horse is not drinking enough water, offer some hay to encourage drinking after eating. Soupy bran or pellet mashes are another means of getting extra water into your horse.

3. Keep a supply of water available for your horse to drink. Obtain some clean 5-gallon cans and fill them up with water before you travel. A 1,000-pound horse not in work, not lactating and not in high heat and humidity needs a minimum of 6 gallons per day. This doubles or triples in high heat and humidity, requiring no less than 12-18 gallons per day.

4. Provide salt and electrolytes as needed. These may be useful if your horse has been sweating excessively. However, horses must consume water to gain the maximum benefit from supplemented electrolytes and avoid dehydration. Ensure that your horse has access to plain, fresh water to encourage appropriate water intake. If you have not used electrolytes before, outline a plan with your veterinarian and be sure to use only electrolytes specifically made for horses.

5. Limit exertion during peak heat. Ride in the early mornings or evenings when it is cooler and keep your rides short. Remember to go slow and provide frequent breaks, in the shade whenever possible.

6. Optimize ventilation in the trailer. Open vents and windows in the trailer, but for safety reasons don’t let your horse stick its head out while on the road.

7. Plan ahead for trailering. Trailer in the early morning or late evening hours when it is cooler.  Never leave horses in a parked trailer, especially if there is no shade. Temperatures inside a trailer can rapidly reach 140 degrees and horses can quickly develop heat stroke. Provide as much ventilation and airflow as safely possible on the road. Be very careful when hauling foals, as they are more susceptible to heat than adult horses.

8. Provide shade. Provide your horse with as much shade as possible. Trees, run-in sheds, and other structures with good ventilation can give your horse relief from the sun.

9. Ensure good air circulation in barns. Open windows and doors in barns to provide cross-ventilation. Try to arrange for more air circulation by careful placement of fans in front of the stalls or in the aisle ways. Be sure to keep electric cords out of reach of horses. Exercise caution with any electrical appliances in a barn as faulty wiring or inadequate circuits can cause a fire.

10. To lower body temperature, hose off your horse or pour a bucket of water over your horse. Evaporation produces cooling and continuous hosing is one of the most effective means of lowering body temperature. Use water that is cool or lukewarm, but never hot. Studies have shown that one of the best ways to cool your hot, sweaty horse is to provide a whole-body shower. The colder the water, the faster the core body temperature will come down. Continuous application of water is ideal. Research has also shown that sweat scraping, or removing the water from the horse’s coat, is not necessary. Failing to remove excess water will not make your horse any hotter or have detrimental effects on health.

Contact your veterinarian immediately if you think that your horse is experiencing heat-related issues, such as dehydration, exhaustion or heat stroke, as these can lead to serious illness.

*This article may not be reproduced without the written consent of the UC Davis Center for Equine Health. Please email requests to cehadmin@ucdavis.edu.