Heat Advisory for Horses

John Madigan, DVM, DACVIM, ACAW , International Animal Welfare Training Institute; Gary Magdesian, DVM, DACVIM, DACVECC , Head, Equine Critical Care, William R. Pritchard Veteri -  nary Medical Teaching Hospital; and W. David Wilson, BVMS, MS, MRCVS  Director, William R. Pritchard Veterinary Medical Teaching Hospital, School of Veterinary Medicine, University of California,

Last summer produced record hot temperatures throughout northern California.  Many horse events are scheduled during this time.  Here are ten important tips to prevent heat-related problems in horses.

1.  Heat can kill — High environmental temperatures and related heat issues of dehydration, exhaustion, and heat stroke can occur in horses and can produce illness and death. This is serious business and you must take steps to ensure your horse is protected when traveling in a trailer, being ridden on trail rides, or in competition events.

2. Know signs of fatigue and overheating  in your horse and stop before more severe signs of heat exhaustion begin.
>>   Persistent high respiratory rate that does not come down with rest over 10-30 minutes (normal is 20-40 breaths per min).
>>   Change in mental activity and decreased energy level.
>>   Dry mucous membranes in the mouth (they should feel “slimy”) and prolonged capillary refill time. To test, pushon your horse’s gums. They should be pink to start, then they will blanch to white after pressure and return to pink in approximately one to two seconds.  Check this at the start of your day and frequently throughout the day. If it is prolonged, contact your veterinarian.
>>   Gut sounds — Listen at the start of your day (if you don’t have a stethoscope put your ear on your horse’s flank, behind the ribs). You should hear gurgling sounds on both sides of the belly within seconds. Gurgling sounds are normal and good. Quiet gut sounds are a warning that your horse may be heading for dehydration or exhaustion.

3.  Drink water — Maintain hydration in your horse by allowing free access to water at all times during hot weather. It  is a myth that a hot horse drinking water will experience colic or other medical problems. Never let your horse pass up a chance to drink water. Only horses that have been deprived of water for a significant time (many hours or days) need to have water provided in smaller amounts over time under veterinary direction. Let your horse drink on the trail or  after a class at a show.  If you think your horse is not drinking enough water, offer some hay to encourage drinking after eating. Soup-consistency bran or pellet mashes are another means of getting extra water into your horse.

4.  Shade — Provide shade as much as possible.

5. Limit what you do with your horse during peak heat:
>>  Ride or compete with your horse in the early mornings or evenings when it is cooler.
>>  Shorten your ride.
>>  Go slower and provide frequent breaks for your horse, in shade.
>>  Encourage your horse to drink whenever they want water.

6. Ventilation — Provide open vents and windows in trailers which can open for cross ventilation (however, don’t let your horse stick its head out while on the road).

7. Fans — If in a barn with limited ventilation, try to arrange more air circulation by careful placement of a fan in front of the stall or in the aisle way. 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.  

8. Hose (spray) off your horse or pour water from a bucket over your horse. Cool water is fine, room temperature or lukewarm (but not hot) water is good too. Evaporation produces cooling and continuous hosing is one of the most effective means of lowering body temperature.

9. Water source — 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.

10. Electrolytes — These may be useful if the horse has been sweating excessively. Only use if they can be followed by access to water to drink. Have a plan outlined by your veterinarian if you have not used electrolytes before. Only use electrolytes specifically made for horses. Center for Equine Health (530) 752-6433 www.vetmed.ucdavis.edu/ceh
Trailering in the Heat If you need to trailer your horse, do so in the cool early morning or late evening hours when it is cooler.  Never leave your horse in a parked trailer, especially if there is no shade. Just as with a parked car, temperatures inside a trailer can rapidly reach 140 degrees and the horse can quickly develop heat stroke. Provide as much ventilation and air flow as safely as possible on the road. Be very careful with hauling foals as they are even more susceptible to heat than adult horses. Know the signs of fatigue and overheating  in your horse [described in (2) above] and stop before more severe signs of heat exhaustion begin. Call your veterinarian if your horse has any of these signs.

Source: http://www.vetmed.ucdavis.edu/ceh/docs/ATWOOD-HeatAdvisory.pdf