Horses love to eat. It is an activity they will do non-stop if given the chance. Modern feeding, housing and exercise practices often make continual grazing impractical for us and impossible for our horses, so we feed them concentrated feeds twice daily.
It's only natural that some horses try to gobble up as much food as possible in these brief feedings, and sometimes they simply eat too fast. The end result of this equine gluttony can be a case of choke.
When horses become choked they cannot swallow. However, they can breathe, so the signs of choke in the horse are different from those in a human.
This is because, in humans, the openings to the trachea (windpipe) and the esophagus (feeding pipe) are very close together. Since most obstructions occur in the back of the throat prior to swallowing, both "pipes" are blocked.
There is much more room in the horse's mouth than a human's, and typical cases of choke usually occur after the horse has swallowed its food. The obstruction, therefore, occurs only in the esophagus. Constructed of smooth muscle, this tube stretches from the back of the horse's mouth to the stomach.
Food is chewed and swallowed, then enters the esophagus. A complex set of nerve impulses controls the muscle contractions and relaxations that slowly push or squeeze the bolus of food along the pipe to the stomach.
Typically, horses choke while eating. When choke occurs, they will stop eating and act distressed. The horse may stretch out its neck and try to swallow. It may open and close its mouth frequently. Saliva may drip from the horse's mouth and nostrils, and a watery green material may gradually replace the saliva as partially dissolved food starts to back up in the horse's nasal passages and mouth. The amount of saliva produced by a choking horse can be significant and may be found on stall floors and walls if the situation goes untreated for any length of time.
Some horses tolerate choke better than others do. While in distress, some may salivate and cough up food particles and may try to cram still more food in their mouths. Other horses may be very anxious and nervous at being unable to swallow and may become so stressed that they colic secondary to the choke.
In either case, it is important to get treatment for your horse. A persistent choke can lead to serious consequences. Horses that have been choked for long periods of time become dehydrated, and the excessive saliva loss robs their bodies of significant amounts of electrolytes, worsening the situation.
Distention of the walls of the esophagus by a mass of hard, dry food can cause necrosis (death of tissue) that can lead to muscle tearing or rupture of the esophagus itself. Horses that have been choked for a long period of time are at risk of aspiration pneumonia, which can also be a potentially fatal complication. Because horses can continue to breathe while choked, they may breathe some of the food-contaminated saliva into their lungs. This bacteria-rich food solution causes rapid infection in the lungs and can lead to pneumonia.
Choke should be considered a minor emergency. Many times removing all remaining food, trying to relax the horse and gently massaging its neck and throat area may be enough to allow the food to pass. While massage can soothe the horse and soften the food mass, bear in mind that your massage must be gentle.
Modern veterinary treatment for choke consists of tranquilization of the horse and use of a nasogastric tube to soften the food mass. The veterinarian will pass a tube into the horse's nostril, through the sinuses, past the back of the throat and into the esophagus to the level of the blockage.
The veterinarian will repeatedly flush warm water and withdraw it through the tube in an attempt to dissolve the packed food. Small chokes can be easily relieved in this manner, while serious chokes may take hours to dissolve. Surgery can occasionally be used to relieve a choke that cannot be unblocked by a nasogastric tube.
Because of the threat of choke following feeding, it is never advisable to feed your horses so late that they cannot be observed for a period of time after they have finished eating. Putting food in their buckets and then leaving the barn can lead to a serious situation if a choking horse is not found until the next morning.
Ken Marcella, D.V.M., is based at the Chattahoochee Equine Center in Canton, Ga.
Pellets Aren't the Bad Guys
Many owners blame feeds such as pellets for choke. While pellets can be easily bolted and may need more water in order to dissolve, it is the manner in which the horse eats, rather than the foodstuff, that causes choke. Putting two rounded, grapefruit-sized rocks in the feed bucket may be all that is needed to keep a horse from gobbling its feed.
Horses should be fed individually or in a situation that does not promote bolting. Some horses may gobble food very quickly to avoid being pushed away by more dominant stablemates.
The horse that bolts its food is not the only animal at risk for choke. Sometimes horses choke because the esophagus is constricted by a tumor, scar tissue or an abnormal out-pouching of the tube itself. These conditions require surgical intervention.
Poor chewing and eating habits can also contribute to frequent chokes. Horses should have their teeth checked on a regular basis and floated if necessary.
Access to plenty of fresh water during feeding is also critical, no matter what type of feed you use.