Description

Esophageal choke usually occurs when a horse bolts down incompletely chewed feed or foreign objects. Hay is often the culprit, or it may be a large chunk of food such as a piece of apple, carrot, beet pulp, or other object. 

Esophageal obstruction or choke can be a primary or secondary problem. Primary obstruction is usually caused by a foreign object or too much roughage being swallowed at one time.

Secondary obstruction is caused by an abnormality in the esophagus. Tumors, strictures, and cysts are examples of intramural abnormalities. Neck and mediastinal masses, as well as vascular anomalies such as defects of the heart and major blood vessels are considered to be extramural abnormalities. Any of these conditions can contribute to choke.

When horses have had esophageal trauma, or if they have dental abnormalities or ongoing dehydration that compromises swallowing action, they may become predisposed to choke. Greedy eaters that do not take time to chew their food are also susceptible to choke.

The diagnosis of choke requires a complete physical examination to rule out different diagnoses related to other ongoing physical problems.

Symptoms

• Anxiety
• Retching
• Extended neck
• Gagging
• Obviously painful swallowing
• Frothy nasal discharge
• Excessive salivation
• Coughing and blowing food out through the nose and mouth

Causes

Choke occurs when food gets stuck somewhere between the mouth and stomach within the esophagus, which is a tube about 50 inches long in a mature horse. Horses that choke are usually in an acutely distressed state and care should be taken to resolve the problem as soon as possible.

Often, a partially chewed wad of hay will lead to choke, but large pieces of apple, carrot, corn cob, or a mass of beet pulp may precipitate the condition.

When the weather turns cold and water is cold or frozen, horses drink less and this can lead to dehydration that may inhibit the smooth passage of food from mouth to stomach.

Choke can also occur because of physical trauma or abnormalities. Dental problems that cause a horse to swallow partially chewed food can be a cause, as well as tumors, strictures, cysts, and diverticula (a dilated area) in the esophagus. Neck and chest masses and vascular ring anomalies also affect a horse's ability to swallow food.

Prevention

Preventative precautions include making sure that horses have plenty of clean, fresh water available, especially when they are eating dried hay and similar foods. When feeding apples, carrots, beet pulp, and similar goods, make sure that the portions are small enough to be easily chewed and swallowed.

Avoid leaving foreign objects around that may tempt a horse to try eating the non-food item, such as a ball of twine, that might precipitate choking.

If a horse tends to bolt food, place large rocks in the feeder so the horse will have to "forage." Soak food for older horses or horses that have dental problems, and, in some cases, it may be necessary to choose feed that can be offered as gruel or mash or as an easily chewed and swallowed mixture. Avoid poor quality hay with large stems and grass clippings.

If a horse rushes eating because he fears another horse might steal his food, feed him away from other horses. Also, feeding smaller amounts more often will work well with some horses.

Treatment

The prognosis for complete recovery after one bout of choke is good. Once you are aware that a horse is choking, the horse should be prevented from eating or drinking anything further. It is best to secure the horse in a safe place and contact a veterinarian for advice.

Frequently, the obstruction will clear just from the movements and efforts of the horse. Occasionally, the lump of food can be felt on the left side of the neck and gently massaging the area will help it disperse.

If the problem has not cleared up in a few hours, a veterinarian's assistance will be needed. The vet may sedate the horse to decrease esophageal spasms and to encourage the horse to relax and put the head down.

It may be necessary to pass a nasogastric tube through to the stomach and use warm water to clear out the obstruction. Surgery (esophagostomy) is the last choice in most cases.

Secondary complications of choke may become problematic. They include dehydration, blood pH abnormalities, aspiration pneumonia, esophageal ulceration, strictures, ruptures, or enlargement. Follow-up care is extremely important, and the horse should be kept off food for 48 to 72 hours.

It is best to begin feeding a soft feed, such as mash, until all healing has taken place. Endoscopy may be used to evaluate the esophagus to make sure that any ulcers or strictures are healing.

Broad spectrum antibiotics are an important treatment in many cases, and ultrasound may be used to evaluate the lungs for aspiration pneumonia. Oral and intravenous fluids to correct electrolyte imbalances may be necessary if the horse suffers from choke over a period of time.

Proper diagnosis and therapy are extremely important in preventing serious injury to the horse and in preventing future episodes of choke.