Unlike the term in human medicine the trachea or windpipe is not affected in equine choke. Choke occurs when the oesophagus, the pipe between the mouth and the stomach, becomes obstructed by food or a foreign body. Typically this may occur in horses that eat dry food too rapidly. Sugar beet often causes problems because, unless it is thoroughly soaked beforehand, it tends to swell rapidly when mixed with saliva as it is being chewed. As the food bolus increases in volume, its passage down the oesophagus slows and eventually it becomes lodged.
The first sign in some horses may be panic as they make repeated unsuccessful attempts to swallow the food. Subsequently the horse tends to tense all their neck muscles. Further signs may be a nasal discharge of food and saliva, depression and inappetance.
Choke is a common condition and, although at the time it may look very dramatic, the obstruction usually clears by the time a vet arrives. It is important to notify your veterinary surgeon as soon as you suspect that your horse may be choking, they can then give you suitable advice and organise a visit.