Updated: Mar 13
Hyperthermia is a state of abnormally high body temperature. High environmental temperature and/or overexertion can cause hyperthermia, which results in exhaustion. If severe, heat exhaustion becomes heatstroke. Hyperthermia is considered under shock because it will result in shock if left untreated. Signs of hyperthermia include the following:
elevated temperatures (105-108*F)
The most important therapy for heat stroke or heat exhaustion is rapid cooling of the horse's body. This should be done immediately while waiting for the veterinarian's arrival. The animal should be placed in the shade or under an improvised shelter and sprayed with lukewarm or cool water. Once the horse's temperature has decreased to 104*F, spraying should be stopped to avoid occurrence of shock. Immersion in cold water, in a pond or stream, is not suggested, as drowning can occur due to the animal's weak and debilitated condition.
Ice packs applied to the head will help the horse recover his sense of orientation, and ice applied to the feet will aid in preventing laminitis, a possible sequela to hyperthermia. The horse can also be treated with a cold water enema. If possible, the animal should stand where there is a breeze, or electric fans can be used in a stall.
Most horses will become very thirsty and will attempt to drink a large amount of water within 15 minutes of the beginning of treatment. Water should be available but intake should be controlled in order to prevent laminitis. The veterinarian may administer fluids intravenously to replenish the horse's body fluids.
The grain rations of the horses with hyperthermia should be reduced to help prevent laminitis, but all affected animals should be allowed plenty of water, salt, and hay. Heatstroke or heat exhaustion requires a seven to ten day recovery period, during which the horse should be gradually reconditioned. After an attack, a horse will often be unable to perform strenuous exercise while the weather remains hot.