In humans, the term ‘choke’ refers to an obstruction of the airway and is immediately life threatening. In horses, ‘choke’ is an obstruction of the esophagus, or the tube that carries food from the back of the mouth down into the stomach. Horses can have partial or complete obstructions. So what causes a horse to choke in the first place? There are several different reasons a horse can become choked. The most common cause is feed that is ingested dry, but once chewed and mixed with saliva starts to expand. It can expand while in the esophagus, which slows the food bolus down or completely stops it all together. The problem then becomes compounded if the horse continues to eat, piling more feed on top of the clogged tube. Other causes of esophageal obstruction include bolting feed (eating quickly, usually due to competition for feed or being a pony), problems with the horses dentition (missing teeth, uneven arcades, sharp points), or another underlying disease (masses, motility issues, botulism, etc).
So how do you recognize that a horse is choking? Horses who have become choked will stop eating and drinking, usually become lethargic (but sometimes get agitated), stretch their neck out in an attempt to clear the blockage, have difficulty swallowing, and may cough or gag. Many horses will have saliva mixed with feed material coming out of both of their nostrils and sometimes you can feel a lump on the left side of their neck where their esophagus runs. The most important thing to do is not to panic! Keep your horse in a safe area where he doesn’t have access to food and seek further advice.
Many chokes will resolve themselves on their own. Sedating with acepromazine to make the horse calm and relaxed, with his head down, can be enough to clear many obstructions. Some blockages are more tenacious (like the ones in your sink that won’t resolve with Drano) and will require veterinary attention. The horse will be given sedation and an anti-inflammatory drug. A nasogastric tube will then be carefully passed, using water to break up the obstruction as the tube is advanced further down the esophagus. This process can take a long time, and is often quite messy, as care needs to be taken to not put too much pressure on the esophagus itself. One of the biggest worries with any choke is rupture of the esophagus, either as a direct result of the blockage, or from attempts to clear the obstruction. The other common complication is pneumonia as a result of aspirating feed material and water. This is why antibiotics are often given when a choke is relieved to help prevent a respiratory tract infection.
So now everyone involved is covered in feed material, saliva and water, but the horse is no longer choked! It is a good idea to give the esophagus at least a 24 hour rest from solid foods. Giving the horse access to water, but not food, will allow the tissue in the esophagus to heal with minimal scarring, thus helping to prevent future chokes. The horse should then be fed soft mashes for 2-3 days before returning to its normal diet. Horses who have repeated episodes of choke should be examined in an attempt to determine any underlying causes. For horses who eat too quickly, feeding them away from other horses may help or adding a large rock or brick to their feed tub to slow them down may be enough to solve the problem. Soaking feeds and feeding them in a mash form may also help. Feeding smaller amounts more frequently or changing up the horses feed are other considerations. Sometimes older horses who don’t have many teeth left need to be kept away from hay and only fed soupy mashes.
As traumatic as choke can be for an owner to witness, the prognosis for recovery is good. As long as the esophageal obstruction is caught fairly early and not allowed to persist for a long time, most horses recover with no long term complications. For those fast eaters out there, remember that an ounce of prevention is worth a pound of cure!