A Selection of Common Equine Pathologies

Equine massage course materials. Copyright, Sara Light-Waller 2010-2019 All Rights Reserved.

Articular Windpuffs – Chronic swellings on or near the fetlock joint. The swellings look like small, soft, fluid-filled pouches. The exact cause is unknown although as they occur in horses with rather straight fetlocks in hard training schedules, it seems that conformation plays a role. The horse will not be lame. Windpuffs are considered a cosmetic blemish. Pressure bandages can sometimes temporarily reduce the swellings, but this is not a cure.

Azoturia, tying-up, & endurance-related myopathy – These are a group of muscular disorders caused by exertion and most frequently seen in performance horses. In them, excessive quantities of nitrogen waste products can be found in the urine of the affected animal. These disorders are usually the result of exercise following a period of inactivity during which the horse is maintained on a full diet rich in carbohydrates (grain).

Azoturia is the most severe form of this type of disorder. Originally called, “Monday Morning Sickness,” it was frequently observed in heavy work horses on the first day back to work after the weekend. Signs include profuse sweating, increased heart and respiratory rates, fever, muscle stiffness and spasms. It is often difficult to distinguish azoturia from severe colic. Urine will be a red-brown to black color depending on the degree of muscle break down. Kidney failure may develop if proper treatment is not instituted.

Tying-up is a mild form of azoturia. Affected horses may or may not have discolored urine. The condition commonly occurs at the start of, or when the horse has cooled down after, vigorous exercise. The muscles will be hard upon palpation and the animal will be reluctant to move.

Endurance-related myopathy is similar to tying-up but occurs in adequately conditioned horses that have been pushed past their level of conditioning. Affected horses may be severely dehydrated with salt and water mineral imbalances in the blood.

Treatments, administered by a veterinarian, will include tranquilizers, intravenous fluid therapy, anti-inflamatories, and possibly muscle relaxants. For horses that frequently tie-up exercise and diet management is indicated.

Bog Spavin (Tarsocrural Synovitis) –A chronic distention of the tarsocrural joint capsule. It appears on the dorsomedial aspect of the hock joint (that is, the upper inside section of the hock). A common disorder found in athletic horses caused by trauma, an injury to the joint capsule or ligaments, conformational faults (post legged or straight behind, sickle-hocked, cow-hocked), osteochondrosis, lesions causing tissue irritation in the surrounding tissues, and mineral or vitamin imbalances. Frequently there are no signs of lameness, no heat or pain with palpation. True bog spavin has no real treatment other then for cosmetic reasons. The synovial lining inflammation can be brought down with a joint injection of corticosteroids.

Bone Spavin – This is the most common cause of chronic hindlimb lameness in the equine. Although probably most commonly seen in Standardbred racehorses, older performance horses of all types can get bone spavin. Bone spavin is an osteoarthritis of the tarsal bones. Poor conformation is the main cause. Sickle-hocked or cow-hocked horses have a predisposition for this problem. These conformational defects create a greater stress on the medial aspect of the hock joint and the additional stresses can lead to development of this condition. Bone spavin is a condition to be addressed by a veterinarian.

Colic –A stomach ache that can range from mild to severe, colic is one of the most common equine disorders. It can be caused by many different conditions including parasites, twists in the intestines, diseases of any abdominal organ, stress, and diet. Dietary colic can be classified into several categories including: gas, impaction, sand, and spasmodic colic. Signs of colic can include: restlessness, sweating, pawing, repeatedly turning to look at the stomach, lying down and not resting, rolling and thrashing, getting up and down repeatedly, increased heart and respiratory rates and pale gums. At the first sign of colic the veterinarian should be called. While waiting for the vet’s arrival gentle massage can help the horse relax.   

Laminitis (Founder) – This disorder is characterized by an inflammation of the laminae of the foot, which serve to attach the distal phalanx (coffin bone) to the hoof wall. In the most severe cases the distal phalanx may rotate and puncture through the sole of the foot. Although it can afflict any foot, the front feet are the most commonly affected.

Laminitis can affect young or old, equine athletes or backyard companions. Any breed is susceptible. Although some diseases may predispose an animal to laminitis, by and large, most cases are brought on by poor animal husbandry practices. It can be caused by a number of factors including overeating (grain – carbohydrates – or rich pasture), drinking cold water, extreme concussion or trauma to the feet, systemic infection, and/or certain anti-inflammatory drug treatments. After veterinary intervention further support for recovery can include change of diet, corrective shoeing, warm, moist heat, and physical therapy including massage.

Navicular Syndrome or Disease is one of the most common causes of intermittent forelimb lameness in the horse. Quarter Horse, Standardbred and Thoroughbred geldings seem to be at the greatest risk. Conformational flaws such as upright conformation, and small feet in relation to body size (as is promoted in the breeding programs of some equine breeds) are thought be the primary causes of navicular syndrome. The concussive effects from working on hard surfaces, and improper shoeing and foot trimming can aggravate the condition.

Navicular encompasses a broad spectrum of conditions that affect the navicular bone (or distal seasmoid – the small bone caudal to the distal phalanx), its bursa and the flexor tendons. Horses with navicular attempt to avoid landing on their heels and will appear to be trying to land on their toes. This will give them a  look of “walking on eggshells” when they move. This is a degenerative condition and both treatment and potential recovery are dependent on the degree of severity and the progress of the disease. In the most severe cases the navicular bone may fracture and the deep flexor tendon may rupture.

Scoliosis, Lordosis – As in the human, both scoliosis and lordosis can be either congenital or acquired. Both are relatively uncommon in horses, although lordosis or “sway back” can also be seen in elderly horses. A horse with a severe, congenital scoliosis or lordosis is considered unusable.

Tendonitis – A frequent occurrence in horses, tendonitis is an inflammation of  a tendon or tendon muscle attachment due to either exercise or trauma. The superficial digital flexor tendon is the one most commonly affected. This condition is frequently seem in racing Thoroughbreds and Quarter horses. It can range from mild to a complete rupture of the tendon. Horses with acute tendonitis will typically demonstrate pain in the affected limb with heat, swelling, and tenderness upon palpation. Acute tendonitis is commonly referred to as a “bowed” tendon.” Initial therapies include: cold hydrotherapy, ice packs, support bandaging, and anti-inflammatories. Stall rest is indicated. Horses with tendonitis will have a variable prognosis depending on the severity of the injury. If the condition is mild the horse will have a fairly good chance of returning the health and work, although the tendon is unlikely to ever regain it’s original strength.