The most common disorder of the esophagus is an obstructive disorder commonly referred to as choke. The clinical signs include stretching of the head and neck, restlessness, drooling (or excessive salivation) attempts to swallow that may result in coughing, a feed-tinged discharge from the nostrils, bad breath, and possibly a lump at the site of obstruction. Choke may have many different causes, e.g., feed, wood, or foreign bodies.
Sometimes the discharge can be greater, when choking on chemically cured alfalfa it is more rapid and green in color. Usually horses get over it by themselves.
A common predisposing factor for choke is improper mastication (chewing). Causes of poor mastication include poor teeth in older horses, erupting teeth in younger horses, greedy eating, exhaustion, and depressed swallowing reflexes from general anesthesia (as would occur following a surgical procedure). Other possible causes include a narrowing (stricture) of the esophagus, and tears or outpouchings (diverticula) of the esophagus that become impacted and occluded with feed.
Most cases of simple choke resolve spontaneously; however, the more quickly they are relieved, the less injury will be sustained by the esophagus. Feed and water should be removed from a horse if choke is suspected. An examination by a veterinarian is recommended to ascertain the cause and to provide a course of treatment. If the choke cannot be attributed to a simple cause—such as bad teeth or greedy eating—the prognosis may be less optimistic, as is the case with strictures and diverticula of the esophagus.
During the last year I came across seven cases of choking, all of them on pelleted feeds. The pellets will turn back into fine powder while chewed by the horse, sometimes resulting in choking, usually due to insufficient moisture (saliva) in the food passing into the esophagus and getting stuck in form of dough like mass. Hence, pay attention especially after hard work when the horse’s system was depleted of water. Preferably feed mash in such cases. The fine chemically cured alfalfa, when fed after strenuous exercise (race) when the depletion of water is significant, will also increase the chances of choking. Most horses that choked did not have free access to hay.