Horses with choke are seen relatively frequently, and it is usually caused by a blockage in the oesophagus (the tube between the mouth and the stomach). Choked horses are often distressed with lots of saliva mixed with food coming down both nostrils. They may show arching of the neck and spasms of retching. 

The most common cause of choke is obstruction from a ball of food material, such as unsoaked sugar beet, dry nuts or coarse mix, poorly chewed roughage or even unwatered bedding pellets. 

The first action to take if your horse has choke is to remove all food, water or edible bedding. Many cases will clear by themselves within an hour but some will require veterinary attention. To try to avoid choke ensure that your horse has regular dental attention so that foodstuffs are chewed effectively before swallowing. Also, preventing a greedy horse from bolting his food by feeding it on its own from a wide, shallow bowl can be beneficial.