Is Your Horse Ready for the Heat?
Summer is here, and that means longer days and hotter weather. Many horse owners have plans to compete, trail ride, drive, or seek other athletic endeavors with their horses. The summer heat and humidity, however, can place high demands on our horses’ thermoregulatory system.
Your horse’s thermoregulatory mechanisms
Horses cool themselves by sweating, which causes evaporative heat loss. In hot weather, a working horse can lose 2-4 gallons of sweat per hour. When the humidity is high, that sweat does not evaporate, and horses can’t cool themselves efficiently.
Steps to keep your horse cool:
- Provide adequate shade and ventilation.
- Avoid working horses when combined temperature and relative humidity value exceeds 150.
- Provide plenty of cool water. Clean water buckets and troughs frequently as blue green algae is more likely to form in hotter temperatures. Don’t rely solely on ponds or slow moving streams for water as fatal blue green algae can form easily in hot conditions.
- Provide free choice salt (loose is better than a block).
- Don’t work your horse beyond his/her fitness level.
- Ensure your horse sheds their hair coat out well. If not, he/she may have equine Cushing’s syndrome. This condition is treatable by medications. You may also need to clip your horse’s hair coat to prevent overheating.
- Provide oral electrolytes to horses that have been sweating excessively or who may have demands that cause them to sweat excessively.
- If you must, work horses in the cooler times of the day.
- Do not withhold water from a hot horse. Allow them a few swallows every few minutes to help them rehydrate.
- Monitor your horse for sweating. If you believe his/her sweating is inadequate, he/she may have anhidrosis (inability to sweat). Please consult our office if you are concerned your horse has this condition.
How to cool your horse:
A horse overheats when its temperature reaches 103°F. To cool an overheated horse, spray or sponge the horse with cool water and scrape off immediately. The heat from your horse is transferred to the water rather quickly. If it is not scraped off, it could act as an insulator and cause your horse to overheat. Areas where blood vessels are closer to the skin surface (ribs, head, and legs) are more responsive to cooling.
A horse is suffering from heat stroke when their rectal temperature is 106°F or above. Signs of heat stress include rapid heart and respiratory rates that don’t improve within 20 minutes following the cessation of exercise, incoordination, distress whinnies, prolonged skin tent (4-10 seconds), incoordination, and collapse. Heat stroke/stress is an emergency. Call your veterinarian as he/she will likely need to administer intravenous fluids to restore fluid and electrolyte levels. Move your horse to a shaded, well-ventilated area. Apply cool water or ice water as described above to initiate cooling by evaporation. Fans can aid in the evaporation process.