Esophageal obstruction also known as “choke” is a common emergency call for equine veterinarians. The obstruction of the esophagus can be caused by many things that block the esophagus and prevent the horse from swallowing. This condition is considered an emergency situation and the horse needs immediate medical attention. Uncomplicated chokes can be resolved with simple treatment techniques, while more complicated chokes may take more vigorous and intensive treatments. The majority of chokes can be prevented.
The esophagus is a muscular tube about 4-5 feet in length, which moves food from the mouth and throat to the stomach. The esophagus starts at the back of the throat (pharynx) above the wind pipe (trachea), down the left side of the horses’ neck, through the chest cavity (thorax) and ends at the stomach in the abdomen. The most likely place for obstruction of the esophagus is in the pharyngeal area, as the esophagus enters the thorax and before it empties into the stomach.
The most common causes of choke are pelleted feed, beet pulp, hay, and large food objects, (apples, carrots, corn cobs, etc.). Dry feeds like pelleted feeds and beet pulp can absorb saliva and expand in the esophagus causing obstruction. Horses can also choke on moist feed and hay when they aggressively eat and bolt their food. Instead of chewing their food properly they bolt down their food and the esophagus becomes obstructed. Older horses and horses with poor teeth or no teeth can also become obstructed from not being able to chew their feed material properly. Uncut food materials, like apples and carrots can cause obstructions when eaten whole.
Signs of choke in the horse include but are not limited to: bilateral nasal discharge of saliva and food material; stretching out of the neck; coughing; gagging; excessive salivation from the mouth; acting distressed; and decreased appetite. When horses become choked, they have do not have the ability to swallow their salvia or water and can become dehydrated very quickly. Because this is an obstruction of the esophagus, the horse is still able to breath and usually is most likely distressed from not being able to swallow versus not being able to breathe. The longer the obstruction remains in the esophagus, the more likely serious complications may occur. These complications include aspiration pneumonia, stricture of the esophagus from the constant pressure of the obstruction, dehydration from the lack of water intake and excess saliva production.
Diagnosis of esophageal obstruction is fairly easy. A stomach tube is passed through the nostril into the esophagus down to the stomach. In the blocked horse the stomach tube cannot pass completely down into the stomach due to the obstruction. There are also times that the obstructed object can be felt or seen along the neck.
Treatment starts with sedating and passing a stomach tube to the point of blockage. With the stomach tube in place against the blockage, gentle flushing with warm water can soften the dried feed material and help move the blockage on into the stomach. The addition of a drug that reduces muscular spasms of the esophagus may also help to remove the blockage along with the flushing of the feed material. More complicated and severe blockages may require more intensive treatment, including general anesthesia for complete relaxation of the esophagus and to protect the horse’s airway from aspiration of the feed material. The worst case scenario is surgical removal of the blockage from the esophagus.
Aftercare of mild choke cases may consist of anti-inflammatory drugs and withholding feed for a few hours after resolving the obstruction. More severe and prolonged cases may require antibiotics for possible aspiration pneumonia, and IV fluid therapy for dehydration.
Prevention of choke can be as simple as soaking dry feed materials and cutting apples or carrots into bite size treats. To prevent horses that are aggressive with their feed, one can add large rocks, or salt blocks in the container that the horse is fed in. The additions of these objects will force the horse to root around the objects to find the feed and requiring the horse to eat slower. Good dental care is another way to prevent horses from choking. Horses with poor dentition do not have the ability to chew their food properly. Older horses with few or no teeth have to rely on soaked food to prevent obstruction.
Esophageal obstructions can be very stressful times for you and your horse. With consistent dental care and observing your horse’s behavior, choke episodes can be prevented or at least made fewer in occurrence and less severe.