Knowledge of horse physiology helps protect animal health and owner investment

Horse owners have a better chance of detecting disease and stress in a horse if they are familiar with the normal behavior and physiological parameters of the animal.

Familiarity with what constitutes “normal” for a horse allows equine managers to respond quickly to abrupt or sizable changes, said Dave Freeman, Oklahoma Cooperative Extension Service equine specialist.

“Some horses are naturally calm, others extremely active; some are aggressive eaters, others are slow and picky,” Freeman said. “Horse behavior can be expected to change during certain times, such as foaling, weaning or when horses are moved to new environments or are placed with new horses.”

Freeman said a good horse manager knows the individual behavior for each horse. Changes from that normal behavior should be followed up with more quantitative measurements.

A horse’s heart rate will vary from resting rates of 30 beats to 40 beats per minute to highs of more than 200 beats per minute during extreme stress or intense exercise. Heart rate can be estimated by taking the horse’s pulse from arteries which traverse the jaw or from those arteries located in the lower leg.

“An elevated heart rate while a horse is at rest is a sign the animal is in pain or stressed,” Freeman said.

Respiration rates for resting mature horses should be around 12 breaths to 16 breaths per minute. This rate is significantly increased when the horse is sick or stressed.

“Respiration rate can be expected to be highly variable even under normal behavior and health,” Freeman said. “However, consistent rapid, shallow breaths are an example of signs of stress.”

A horse’s normal temperature of around 101 degrees Fahrenheit likewise will increase when the animal is in a diseased or distressed state. Temperature can be higher and still remain within normal parameters when horses are housed outside in hot weather or in the case of newborn foals.

“Still, a rise in temperature is one of the most conclusive signs that something abnormal is occurring in the horse,” Freeman said.

Temperature parameters are easily monitored by horse owners, and should be recorded in a horse’s permanent file.

Freeman recommends inexperienced owners have their local veterinarians show them the proper techniques.

“The actual task of monitoring temperatures parameters can alter the observable results so a watchful, experienced eye must relate the measurements with other indicators of a horse’s stress status,” Freeman said.

Horse owners or local veterinarians can use this information to diagnosis problems more quickly, thereby increasing chances of a rapid recovery for the horse.

_{Additional information on the physiological responses of horses is available on the Internet and through Oklahoma Cooperative Extension Service county offices by asking for Oklahoma State University Extension Fact Sheet No. 9118, “Monitoring Fitness of Horses by Heart Rate.”

The statewide Oklahoma Cooperative Extension Service system is part of OSU’s Division of Agricultural Sciences and Natural Resources.}