Friday, July 19, 2013

Equine Heat Stress and Heat Stroke

From the CHA (Certified Horsemanship Association) July Newsletter

Equine Heat Stress and Heat Stroke
Summer time! And the heat is rising. In the winter we look forward to summer months of intense equine activity. But are we ready for the heat and humidity?

Prevention is the key to riding in the heat. Horses must be in condition and riders should know the signs of heat stress and heat stroke - and how to react. Water should be offered often, even during exercise. Horses are cooled by sweating and respiration. The evaporation of sweat cools the body. If the day is humid, regardless of the temperature, sweat will not evaporate. If the humidity is high there can be significant losses in water and electrolytes at a temperature of 72 degrees, resulting in dehydration. In extreme dry heat horses can quickly become dehydrated due to loss of fluids and electrolytes through sweat.

Respiration is commonly referred to as breathing. A puffing horse is under stress and trying to cool his body. Moisture is lost during the respiration process. The normal respiration rate of an adult horse at rest is 8-16 breaths per minute. Know what is normal for your horse.

Heat stress usually does not require veterinarian intervention, but the horse must be attended. The most commonly observed signs of heat stress are profuse sweating, rapid breathing and a rapid heart rate. When a horse is showing signs of heat stress, stop all work and begin the cooling procedure.

Airflow is important to lowering the body temperature, so refrain from returning him to his stall. Hand walking, preferably in the shade, is one option. If you have access to fans this will help cool his body. Rinse the horse off with cool, not cold, water. Small amounts of water should be given at frequent intervals. Hot horses can colic if allowed to drink a large quantity of water all at once.

Heat stress can quickly become heat stroke; a life threatening condition. A veterinarian needs to be called! The symptoms of heat stroke are dry, hot skin; high pulse (normal pulse rate is 36-42 beats per minute), high respiratory rate and a high temperature. A temperature of 104 degrees for any length of time is a life threatening condition. The average normal temperature of an adult horse at rest is 100 degrees Fahrenheit – 38 degrees Celsius.

While waiting for the veterinarian to arrive, move the horse to a shady area with ventilation, provided by wind or fans. Work on lowering the internal temperature of the horse. Begin applying repeated applications of water on the neck, chest, shoulders, and legs. The water must flow over these areas and run off in order to remove the built up heat. Walk the horse to help dissipate heat through airflow and keep good blood circulation to and from the muscle. Do not throw a wet towel over the head and neck, as it acts as insulation.
Offer the horse sips of water at frequent intervals. Once the veterinarian arrives she will start electrolyte and fluid replacement treatment. There is a condition that horses may develop called anhidrosis - the inability to produce sweat. The cause is still under research, but one theory is the gradual degeneration of the sweat glands due to continued stimulation by a hot humid climate. Many times when these horses are relocated to a cooler region their ability to sweat returns, but these horses are at a higher risk of heat stroke and must be monitored closely.

So, enjoy the summer with your horse, but be aware of your horse’s comfort level. Stop, take a break, and relish the quiet time with your companion.

For information about caring for and feeding horses take the online course “Nutrition for Performance Horses” taught by Eleanor Blazer. Go to for more information and earn CHA discounts on continuing education credit hours for your certification renewal. Visit Eleanor's web site at