from the Vet Corner Archives
Part of Horse Previews Magazine website. Posted on 06/2000; 2:00:00PM.
Veterinary Corner 06/00: Esophageal Obstruction
by Frosty Franklin, DVM
Edgecliff Equine Hospital
S. 1322 Park Road, Spokane, WA 99212 * 509/924-6069
The esophagus is a muscular tube that originates in the back of the mouth and terminates at the stomach. In the adult full sized horse, the esophagus is approximately 48 inches long and serves as a conduit for water, feed, and salivary secretions to the stomach.
Most esophageal disorders in foals and horses are obstructive and are usually due to an intraluminal feed impaction. The predominant sign in horses with esophageal disorders is a difficulty in swallowing, or dysphagia. The characteristics of dysphagia include frequent ineffectual attempts to swallow, stretching of the neck, attempts to retch, salivation, nasal regurgitation of feed mixed with white foamy saliva and coughing and blowing the feed and saliva mixture out the mouth and nose.
Esophageal obstruction should be considered an emergency. Prolonged pressure on the esophageal mucosa lining by the obstructing material can result in extensive tissue damage, with resulting scar formation and stricture. Also, inhalation of feed, saliva and bacteria can result in severe aspiration pneumonia.
Many substances have been identified that can cause esophageal choke, including grain, hay, pelleted feed, corn cobs, pieces of fruit and vegetables, wood shavings and medicinal boluses. In many cases there is a predisposing factor, such as improper mastication in horses with poor dentition, horses recovering from anesthesia or exhaustion.
Some cases of esophageal choke resolve spontaneously. However, once a diagnosis is made, treatment should begin immediately. The most conservative approach is to give one to three milliliters of Acepromazine to a one thousand pound horse. In mild cases this treatment may offer enough muscle relaxation of the esophagus to allow the obstructing feed to pass into the stomach. A nasogastric tube that is smooth and relatively soft can be used cautiously to determine the location of the obstruction. Occasionally, gentle pressure on the feed impaction will alleviate the obstruction. Vigorous pressure should be avoided.
Giving Xylazine will provide proper sedation, relaxation and lower the head, so saliva, feed and fluids trapped above the obstruction are less likely to be inhaled or aspirated. Warm water lavage of the esophagus can begin after the head is lowered and the impacted feed can be washed and advanced down the lumen. The lavage can be continued intermittently with the horse put in a bedded stall or cross-tied. The use of mineral oil or DSS is contraindicated because they might be aspirated.
Horses that have had esophageal choke for 2-3 days before being discovered or treated are more difficult to relieve. These horses are dehydrated and depressed. They also usually have a fever from the aspiration pneumonia. Many times they have very little saliva coming from the nose, but they do repeatedly swallow. These cases can be difficult to recognize as an esophageal choke.
Extended choke cases are treated extensively with IV fluid therapy (preferably with 0.9% Sodium Chloride), broad-spectrum antibiotics and banamine. Once these horses are hydrated with the IV fluid therapy, esophageal lavage and Oxytocin can be used to stimulate smooth muscle contraction of the lower esophagus.
In most cases, these procedures will relieve the esophageal obstruction. If these initial attempts fail and the patient's condition is stable, the horse can be placed under general anesthesia and a cuffed endotracheal tube can be placed in the trachea. The horse's head is then lowered and a copious lavage of the esophagus can continue. The general anesthesia will enhance relaxation of the esophagus and aid in the lavage of the impacted feed obstruction.
If all attempts to dislodge the obstruction are unsuccessful, surgical intervention is indicated. Referral to a surgical center is usually in the best interests of the horse. The type of obstruction, how long the obstruction has been present, cost and aftercare should all be considered.
Minimizing esophageal choke can be accomplished by having an annual dental exam on horses by a veterinarian that has an interest in dentistry. Sedation, a bright light and a mouth speculum are necessary tools to do a proper mouth and dental examination.
In 24 years of equine veterinary medicine, I have seen many causes of choke. By sharing some of them, I hope that perhaps you can avoid choke on your horse.
1. Avoid feeding a large carrot to your horse shortly after sedation and dental work.
2. Avoid feeding aged horses with "bad teeth" pelleted feed without first soaking it in water.
3. Improperly cooling out and watering a racehorse that is both still excited and dehydrated.
4. Avoid feeding grass clippings.
5. Avoid feeding hay to a horse that is excited and upset with the hopes of calming him down.
6. Avoid feeding aged horses poor quality, overly mature hay.
7. Be aware of horses that are "grain hogs." These horses (especially stallions) open their mouths widely and try to stuff a whole gallon of grain in their mouths at once. One way to remedy this is to add three 4-5 inch rocks to the feed pan. This forces the horse to slow down and pick around the rocks for the grain.
8. Avoid feeding large carrots or apples in whole form. Cut them into smaller pieces.