Signs of Sickness – How to read your horse’s behavior

Written by Sue Stuska, Ed.D.

This article originally appeared in Eclectic Horseman Issue No.10

We’re striving to become more sensitive to our horses while we work with them on the ground and while we’re riding. Some horse behaviors, reactions and conditions relate to their physical well-being. Health awareness also becomes more refined with our knowledge and practice. New horse owners, like new moms, are likely to overreact until they find out the true level of seriousness of the particular condition. That’s not bad: it’s a sign of caring. With experience, we determine what situations require the vet and which don’t. This article is designed to strengthen awareness, so for now it may result in more calls to your mentor or vet. It’s always better to check with someone you trust when faced with a condition of unknown seriousness.

Problem signs can appear as a change in your horse’s normal behavior or situation. For example, if your older horse is always slow to warm up and loosen up on cold days, then that’s not cause for alarm; it is a cause for further scrutiny if it begins to happen with your youngster. Since you know your horse best, you are best able to detect changes. Do notice changes over time. It’s easy to see him every day and not notice that he’s gradually losing weight.

This article is not designed to pinpoint the problem; instead, it will help you identify that there is one. The signs here are general warnings which will then lead you with your mentor and/or vet to determine the underlying problem, its severity and cause. Each sign is related to a number of different problems; the sign by itself is not diagnostic. Further behavioral clues, vitals signs (temperature, etc.) and veterinary analysis will be necessary.

Further, this list is not all-inclusive. Perhaps you will write us and add to the list, if you have suggestions please email us.


Apart from his buddies.
The horse who doesn’t come in with his buddies, or lags behind when he’s usually up front, may be feeling poorly or have a lameness problem. If everyone else is cavorting and he’s standing around, or if everyone else is in the middle of the pasture and he’s still standing near the gate, something may be wrong.

Bad breath from the mouth or nostrils may be due to an infected tooth or a sinus infection. Sinus infections may have an associated nasal discharge. Have the vet investigate.

Bowel changes. Little or no manure may indicate a partial or full intestinal blockagethough you may see accompanying abdominal distress first. Hard, dry feces may indicate a dangerously decreased water intake. Particularly in cold weather, horses may not drink enough to keep the mobility of the feed through the digestive tract and develop impaction colic. Diarrhea may be due to the addition of fresh green grass to the diet in the spring, or, in a foal, its dam’s foal heat (estrus). Ongoing explosive diarrhea may be due to Potomac fever Continuing diarrhea can dehydrate horses, and particularly foals, to dangerous limits within hours. Notice changes and relay these to your vet.

Cold extremities. Blood loss, internal bleeding, severe injury and poisoning can cause shock that keeps the legs and ears from getting enough blood to stay warm. Do look for other signs. It is normal for the horse’s legs to be cold to the touch in the wintertimeparticularly if he is in the snow. His blood flow allows his body to keep warm and retains some blood flow to the extremities.

Coughing is the horse’s way of ridding his respiratory tract of irritating matter. Listen for a wet (mucus) versus a dry (dust) cough. Look for sources of irritants, and if a cough persists, talk with your vet.

Cranky with other horses. Watch the way he interacts with other horses. Pastured horses establish their own pecking order. There will still be some bantering, but you’ll be able to predict which horses will be involved and how it will end (the old mare chases off the young gelding with her ears pinned back and he stays a respectful distance away). While there may not be a disease associated with changes in his herd status, you may need to change his herd mates or isolate him for his health. Mares sometimes show prolonged or strong estrus behavior due to hormone imbalance. If she has been fine with other horses around at shows or clinics, but starts to act peeved, look for the reason(s).

Depression. Listlessness may indicate a fever. Fever is often a sign that the horse is fighting off an infection. Take the horse’s
temperature and look for other signs.

Diaphragm area muscle spasms coordinated with breathing are called “thumps” and result from severe overexertion and electrolyte imbalance. Thumps spasms are not dangerous in themselves, but point to a veterinary emergency.

Excitability, when alternated with periods of abnormal lack of response to the surroundings, can point to nervous system damage from disease or poisoning. Other symptoms may include abnormal reflex actions, uncontrolled circling, and/or head pressing against a solid object. Rabies sometimes causes agitation and aggressive actions. Call vet immediately.

Eye closed, partially closed, or tearing. When tearing fails to clear the eye of irritants, or when the eye is painful, the cause could be as minor as dust or inflammation or as major as an ulcer on the cornea. Unless your horse has been treated for conjunctivitis (inflammation of the mucous membranes of the eye) before and you recognize the symptoms, call the vet. In any eye injury situation, do not hesitate to call the vet because eyesight-threatening conditions do not necessarily appear serious without diagnostic testing.

Feed dribbling out the nostrils. Choke, in a horse, means that his esophagus is obstructed. The chewed feed will come out his nose and his neck muscles will be visible as he tries to swallow. Paralysis of the pharynx from a disease such as botulism can also interfere with swallowing. Call the vet.

Gait unsteady. This can happen over a short or long period of time. Signs may include lack of coordination, swaying, and weakness. Problems may be due to equine protozoal myelitis (EPM), West Nile Virus (possibly associated with lameness), or wobbles (generally associated with spinal cord damage in the neck). Incoordination coupled with high fever and alternated hypersensitivity and depression may be due to encephalitis or encephalomyelitis (viral nervous system disease, commonly abbreviated EEE, WEE or VEE).

Hay belly may make a horse look “fat” when in reality his abdomen is distended by a diet high in roughage or a heavy parasite load. The latter is dangerous and may be accompanied by a dry, rough, poor coat. Deworming on a regular basis and periodic fecal egg counts can help you and your vet rule out parasite problems.

Head shaking or tossing. These originate in a myriad of causes that may not be easy to discern. Check for bit pinching, rider’s hands causing discomfort, or flies/gnats swarming.

Head held sideways when chewing. Often associated with dropping grain. Check the teeth. Your vet or an equine dentist should check your horse’s teeth once or twice a year routinely and remove any sharp edges by “floating” (filing). A painful tooth will also cause this behavior.

Hindquarter muscles hard. Rock-hard haunch muscles coupled with an unwillingness to move points to tying up (azoturia). This is a painful condition that occurs most often in a hardworking horse, fed high percentages of grain to hay, after a day of rest. Keep the horse’s back and hindquarters warm, don’t move him; and call the vet.

Hoof slapped down. A sore forefoot may cause a normally cooperative horse to refuse to hold the opposite hoof up for cleaning; the added weight is painful.

Jaw swellings. Localized pockets of pus, found under the jaw or at the throat and associated with fever, may be due to strangles. This disease gets its common name from the associated pain which makes swallowing uncomfortable. Swellings alongside the jaw may be associated with emerging adult molars and are not necessarily abnormal but must be noticed so as not to irritate them with the halter or bridle.

Lying down and getting up repeatedly is one common sign of the abdominal pain associated with colic. Other signs are looking at the abdomen, stretching as if to urinate, and rolling repeatedly. Watch long enough to note the horse’s activities, and then call the vet.

Advanced Equine Studies – The Horse’s Respiratory System

Lying down more than normal. This can mean anything from horses taking advantage of a warm sunny day in the winter to founder or an abscess in the hoof which makes standing painful. Collect other information to find out more.

Melanomas are tumors found more often in gray horses with black skin than other color horses. They are most often discovered under the tail, but can occur anywhere on the body. They are not usually painful. Watch them, because they can spread and get in the way of the cinch or invade the digestive tract. While usually slow growing and found in older animals, they can spread like cancer.

Mucus in the feces indicates an inflammation of the bowel. Call the vet.

Nostrils dilated at rest. We expect this immediately after strenuous exercise, but a resting horse with flared nostrils is not getting enough oxygen. Breathing difficulty could be due to heaves (emphysema) or congestion in the lungs. It could be due to a heart problem, a circulatory problem, or a systemic problem (one that affects the whole system) like shock.

Nose swollen. Horses can be bit by snakes, and the nose is a prime target. Look for paired punctures from fangs and watch for swelling that can make this an emergency.

Off feed. One of the first signs that something is amiss is that the horse isn’t interested in his grain, or does not clean up his feed.

Recovery time long. In general, the better the athletic condition of the horse, the faster he will recover from hard work. Judge recovery by heart and breathing rate. If it takes a long time for him to recover from long or hard exercise, he’s not in good enough condition to be doing the work without injury.

Refusal to move. Haunches muscles hard and painful from tying up (azoturia) will discourage the horse from moving. Founder, or any severe pain in the front feet, will also cause the horse to avoid walking.

Saddling or mounting difficulties. A sore back may manifest itself in a normally cooperative horse who starts to drop his back when saddled or fidget when you try to mount. Check the saddle fit.

Scratching. An itchy mane can signal horse lice or mites. Normally a horse would have to be in poor health or under-nourished to get a large enough external parasite load to cause him to rub out patches of hair. However, these pests travel from horse to horse and may not cause obvious discomfort.

Sensitive to touch. Watch for changes in how he reacts to grooming. If he usually enjoys grooming but today he objects when you brush his back, look and feel closely for a sore spot that may have come from a longer-than-usual ride with a saddle that does not fit well or a dirty saddle pad.

Shedding late or not at all. Poor nutrition, a heavy parasite load, and the pituitary tumor associated with Cushing’s disease can cause horses to keep their winter coat; the first two can disrupt the normal spring shedding cycle. Older horses normally grow their winter coats earlier and keep them longer than other horses. Keep your horse on a regular deworming program, and consult with your vet about other possible causes.

Skin growths and lesions may include aural plaques (white spots in the ears which usually do no harm), warts (often on the nose and originating from a virus specific to horses), ringworm (from a fungus), and sarcoids (among tumors, a common type), among others. Skin cancer is more commonly seen in horses with pink (than black) skin. Get veterinary advice.

Stumbling. Tripping may be due to too long an interval between hoof trims; long toes can get in the way. However, nerve damage, poisoning and disease can also cause incoordiation and falls. Watch for other signs, and work your horse loose in an arena or round pen, longe him, or pony him to look for patterns and to determine any related factors.

Sunburn. Horses do sunburn on pink skin areas in summer and winter. Long fly/sunscreen masks help prevent face burns; various sunscreen agents also work if applied regularly.

Sweat. Abdominal pain, founder, and shock may cause sweating which is inconsistent with the air temperature. Call your vet. Uneven sweatingwith dry patchesunder your saddle (other than the length of the spine) merit a closer look. Heavier pressure from the saddle will compromise normal skin function and result in a dry patch. Check and correct your saddle fit.

Tears run down the face. When tears run down the face from the front corner of the eye, the duct that normally takes them into the nose may be blocked. (Humans notice this duct when our tears cause our nose to run.) The vet can unblock this duct with little
trouble at his or her next routine visit.

Third eyelid exposed. The horse’s third eyelid flicks across his eyeball to protect the surface and wipe away irritants. If this normally hidden membrane shows routinely, it may be irritated by foreign matter or have a growth (benign or malignant). An early sign of tetanus is spastic closing of the third eyelid when the jaw is bumped from underneath; this is usually accompanied by general stiffness, muscle spasms (those around the jaw give it the name lockjaw) and a stiff stance.

Unable to rise. A horse that’s lying down and unable or unwilling to get up is in trouble. Stay toward the horse’s back and away from his legs for your safety. Avoid the front legs, since he’ll extend them as he tries to rise. Gather information about the cause. He may have a leg problem, a nerve (brain or spine) injury, or be weak from disease. Call your vet.

Urine dark. Muscle damage associated with tying up can cause dark brown urine. Note that urine in snow has a surprisingly dark orange colorand that’s normal.

This article originally appeared in Eclectic Horseman Issue No.10

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