Horses may develop a bad habit of gulping their food too fast and not chewing it as much as it needs to be before swallowing. In both of these cases the food can actually lodge in the horse's esophagus, resulting in a condition known as choke. Choke is most often not life threatening, but it can be very alarming to both the horse and the owner, and can potentially be problematic if the blockage does not clear on its own.
One of the biggest causes of choke is found in horses that are feed dry feed pellets or hay cubes, or feed that is high in beet pulp. All of these types of feeds are very dry and expand when the moisture in the horse's mouth and digestive tract come into contact with the food. If the horse is in a hurry to eat or is just lazy and doesn't break up the food and mix the saliva in with the feed in the mouth, the food absorbs the moisture further down the throat. This will cause the food to swell in this location of the esophagus, causing a blockage for passage of the rest of the food that will simply pile up on top. In extreme cases of choke the backup of food could reach the opening to the lungs, which can be dangerous and even fatal if the feed gets into the lungs. Horses with choke don't seem to stop eating until the situation becomes very uncomfortable, so it is likely there will be a considerable pile up of food.
The first signs of choke are usually excessive salivation from the mouth during or slightly after eating. The horse will usually stand with his or her head down, and may have a constant discharge from the nostrils that includes pieces of food and partially chewed materials. In some cases the horse will be in pain, pawing at the ground, coughing and appearing to choke. If he or she is having problems breathing they will be nervous and appear panicked.
When you notice the first signs of choke immediately remove all feed but leave lots of fresh water. If the horse is not stabled move them to a stall so they cannot continue to graze. If the lump in the esophagus is in the neck area, a light massaging of the spot can sometimes cause the food to move enough to pass down the esophagus, but do not push or squeeze the area as this can damage the esophagus, resulting in much more severe problems.
If there is fresh running water in the area try inserting a hose in the corner of the horse's mouth and just running water through the mouth, this will trigger a swallowing reflex and add additional moisture, helping to break up the lump. If the blockage is in place for more than an hour and the horse is not able to move it his or herself, contact the vet who can use a stomach tube to add water to the area and break up the blockage. Do not try to push anything down the esophagus with a stomach tube as this can seriously damage the esophagus, resulting in permanent swallowing problems. Feed moist feeds such as gruels for at least 72 hours after the problem to avoid reoccurrence.
Once a horse has had a problem with choke or if you are feeding dry pellets or rations with beet pulp it is important to start moistening the food prior to feeding. In addition bricks or large rocks about the size of a baseball can be put into the feeder to slow the horse's ability to gulp mouthfuls of food at one time.