Indicators of Health or Illness in Horses

Your horse doesn’t really seem sick, maybe just a little dull or not as active as usual. Is there something wrong with him? A veterinarian can determine a horse’s health status, but owners can check general indicators of health to help in deciding whether to call a veterinarian for an examination.

Body Temperature

To take the temperature of the horse you need a thermometer, which you can purchase from your veterinarian, a pharmacy, or a horse equipment shop. Thermometers are available in several types, but the digital ones are easiest to use. Grease the bulb end of the thermometer with petroleum jelly or cooking oil. Stand close to the horse and to the side. Lift the horse’s tail and gently insert the thermometer into the rectum. Push the thermometer against the rectal wall. Do not let go of the thermometer. Digital thermometers will beep when they are ready to be removed. The normal temperature range for a horse is between 37°C and 38°C (99° to 101° F). This can vary a degree or two according to climate and air temperature. Foals and small ponies are at the higher end of the normal scale, while older and larger horses are at the lower end. A horse with an abnormally low or high temperature needs the immediate attention of a vet.

Heart Rate

It’s important to know the average resting heart rate for your particular horse. Heart rate can be measured with a stethoscope (purchased from veterinarian, pharmacy, or tack shop) or by hand. To listen to the heart with a stethoscope, stand on the near side of the horse near the girth. Approximately one hand span up from the base of the chest (sternum), push the stethoscope in behind the muscle above the elbow (the brachial triceps) and press it against the ribs. Often the act of putting the stethoscope on the skin excites the horse, which increases the heart rate, so you may have to wait until the horse settles. Count the beats for one minute. If the horse will not stand still for one minute, count the beats for 15 seconds and multiply the result by four. You will hear two heart sounds that correspond to the heart muscle contracting (systole) and then relaxing (diastole). An approximation of the sounds that you hear are ‘lubb’ (systole) and ‘dupp’ (diastole), although they may be indistinguishable at high heart rates.

The normal heart rate for a horse ranges from 30 to 40 beats per minute (bpm), but this varies quite a bit, especially if the horse is eating, excited, feverish, anemic, hot, exercising, and so on. Young horses generally have a higher heart rate than older horses. Rates of foals at birth are 80 to 120 bpm, older foals are 60 to 80 bpm, and yearlings are about 40 to 60 bpm. In adult horses, the rate will become lower as the horse becomes fitter; for example, a very fit endurance horse can have a resting heart rate of 27 bpm. A horse that is fit will also return to its resting heart rate sooner after exercise than an unfit horse. To measure the heart rate by hand, use an arterial pressure point. These are found on the inside of the lower jaw, the inside of the forearm just in front of the elbow, or on the pastern above the heels.

Respiration Rate

Respiration is the alternating inhalation and exhalation of air. The normal respiration rate for a horse is 8 to 20 breaths per minute. The rate of respiration is measured by counting flank movements either by sight or by placing a hand on the ribcage. Normally you can see a horse breathe in, but not out. If the horse is making an obvious effort to breathe out, it may have a respiratory problem. The respiration rate should never be higher than the heart rate. Younger and smaller horses breathe more often than older and larger horses. Pregnant females also have a higher rate. The respiration rate is increased by exertion, fever, pneumonia, changes in the acidity of the blood (acidosis or alkalosis), anemia, and infectious diseases. Synchronous diaphragmatic flutter (thumps) occurs when the diaphragm contracts in unison with the heart rate and is caused by electrolyte disturbances, usually due to exercise.

Hydration Status

If the horse loses more fluid from its body than is absorbed, it becomes dehydrated, which leads to a reduction in the circulating blood and relatively dry tissues. Dehydration is caused by decreased water intake and/or too much water lost through sweating, diarrhea, or urination. Signs of dehydration are a weak pulse, sunken eyes, and dry, darkened gums.

A check for dehydration is the skin-tenting test in which a fold of skin on the horse’s neck is grasped and pulled up slightly. When the skin is released, it should return to normal in a second or two. It should not stay up like a tent; if it does, this is a sign of significant dehydration. Veterinary attention should be sought quickly if the horse is not drinking.

Mucous Membrane Color and Capillary Refill Time

If the horse is healthy, its mucous membranes will be pink and the capillaries will fill quickly with blood. To determine the mucous membrane color, look at the horse’s gums, which are naturally a shade paler than a human’s. Too pale indicates anemia or shock, yellow shows jaundice, blue indicates a lack of oxygen, and darker red means dehydration and serious metabolic disease. To check the capillary refill time, press against the gum with a fingertip and release. The color should return within two seconds; any longer may indicate shock or dehydration.

Gut Sounds and Appetite

Gut sounds should always be audible and if not present may indicate colic. Place your ear or a stethoscope against the barrel behind the last rib. Listen on both sides. If there are no sounds, call a veterinarian.

Horses vary in their normal appetite; some are naturally very greedy and others are very finicky. It is important that you know what is normal for your horse. A change may mean that he is ill.

Body Condition

You should regularly assess your horse’s body condition. Various scoring systems allow owners to find their horses’ scores on a body condition chart. If your horse is too fat or too thin, take steps to change feed management to bring him into a score near the middle of the chart.

Coat

The coat of a healthy horse lies close to the body and shines. Some colors (bay and black) usually shine more than others (grey and roan). If the coat is standing up, it usually means that the horse is cold, but it can indicate illness. The coat hair stands up because the horse is attempting to trap air and warm itself. In the short term, the condition of a horse’s coat is not affected by illness, but a chronically unwell horse has a dull, rough, or dry coat. Diet can also affect the condition of the coat.

Nasal Discharge

It is quite normal for a horse to have a trickle of liquid in the nostrils, but it should be clear and not sticky. Yellow or green sticky mucus indicates illness.

Behavior

The behavior of individual horses varies enormously, so again it is important that you know what is normal for your horse. A healthy horse should be alert, interested in what is going on around it, sociable with other horses, and willing to move forward when ridden. A healthy horse will, when turned out with other horses, occasionally have a run around, lie down to sleep in the sun, and play with other horses.

When a horse is ill it will not display its normal behavior. It may stand with its head down or lie down more than normal or not at all. The sick horse looks “tucked up” (the flanks are sucked in). The horse will either not be alert or may be excessively anxious. It may keep looking at its flanks and/or paw the ground (signs of abdominal pain). Other behavioral signs of illness include excessive chewing on objects or sudden aggressive behavior. Basically, any changes in normal behavior should be investigated. Checking the temperature, pulse, and respiration is the minimum examination if you suspect that your horse is ill. If you are concerned about anything, you should call your veterinarian.