June 22, 2018
What is Choke?
I often get frantic phone calls from worried owners that their horse has stopped eating his feed and now has feed material and saliva coming from his nostrils and mouth. They try to explain their horse is vomiting, coughing, or gagging, sometimes even acting like colic. The first differential diagnosis on my mind is “choke” or an esophageal obstruction. Choke can be a medical emergency leading to very severe post-traumatic problems if not handled properly or in a timely manner. Some horses will choke on their feed, exhibit clinical signs, and pass the obstruction without veterinary intervention, but many horses require treatment.
Choke begins most commonly with a normal horse having a ravenous appetite. Most choke cases I see are those horses that bolt or dive into their feed bucket with force. They take that first bite or two without completely chewing the feed. This allows the feed to become lodged in their esophagus, starting the choke. I have had horses all my life and like many owners, never heard of or experienced an esophageal obstruction in my horse.
As a horse chews it feed or hay, it salivates and breaks down the feedstuffs into smaller particles to help start the digestion process. The saliva aids to moisten, lubricate, and start some dissolving some of the starches in the feed. When a horse, either due to poor teeth or a ravenous appetite, does not chew the feed it increases its chances of staying intact and dry. The feed can then get trapped in the esophagus on the way to the stomach. At this point the horse may feel some pressure, but generally eats a few more small bites. As more saliva is produced and swallowed, the esophagus, which is clogged with feed, begins to fill all the way up to the throat region or pharynx. The pharynx is the area where the oral cavity splits into the trachea (windpipe) and esophagus. The saliva and feed material begin to spill over into the pharynx stimulating a cough reflex in the horse, which lets the material move thru the nose and mouth. Some horses will become very stressed and panic. They may lie down and roll as if having a colic episode; some horses will just become depressed with feed material pouring out of their nostrils.
I suspect there are some underlying factors that may increase one horse’s chance to choke over that of another horse. As described above, the most common seems to be the overly rapid consumption of feed. Horses with poor teeth or older horses with few teeth may be predisposed, due to their inability to properly masticate or chew their feed. Older horses with heart enlargement may be at an increased risk of choke. This is because as the esophagus goes thru the chest, it must pass over and near the heart. If the heart is enlarged, it may allow for an area of the esophagus to have some compression, thus reducing the ability for the esophagus to expand with the feed bolus. Another predisposing factor to choke can be previous choke episodes that have caused damage to the esophagus, reducing its ability to stretch and move feed along.
Choke can result from a variety of materials. The esophagus can become obstructed from very large or whole pieces of apples and carrots. So please do not feed these types of treats without first cutting them into much smaller pieces. I cannot dissolve a severely lodged apple! If it does not get pushed down, then surgery or endoscopy may be the only other treatment choices. Small sticks in hay can sometimes make it down the esophagus without getting lodged, but occasionally the size or angle of the object may be just right to get caught in the esophagus. Dry Beet Pulp is notorious for causing esophageal obstruction and has many times resulted in some of my most difficult to resolve, and sometimes fatal, choke cases. Like an apple or carrot, I am unable to dissolve the obstructive beet pulp. If lucky, I may be able to loosen and breakup the shreds of beet pulp, removing them slowly through the stomach tube and out the nostrils. Pelleted feed is often the most common feed substrate to cause chokes in horses. This is likely because pellets do not generally require as much chewing as do other feeds and, when eaten quickly, they begin to break apart and absorb moisture in the esophagus. Then the feed bolus basically swells, then dries up, and gets lodged in the esophagus. The esophagus then contracts and squeezes on the feed like wringing out a sponge. This sets the stage for choke that may need veterinary care.
Treatment of choke most often depends on the extent of the obstruction. Many times, by the time I get to the farm, the horse has already cleared the obstruction. In these instances I will pass a nasogastric tube (stomach tube) through the esophagus and into the stomach to confirm the obstruction has cleared. I will generally give the horse a dose of an anti-inflammatory, flunixin, to help with any esophageal pain or inflammation.
In more severe cases of choke, the horse is heavily sedated. This is very important because it allows the horse to relax and let the saliva feed material pour from the nostrils more safely. Then the nasogastric tube is passed carefully into the esophagus to determine the location and approximate extent of the choke. If choke is a pelleted feed, then a gentle, warm water lavage will start dissolving the feed obstruction. At this point, apart from relieving the obstruction, a very important concern is aspiration of the contents into the lungs, which can set up potentially fatal pneumonia. Care must also be taken to avoid perforating or tearing open the esophagus. Warm water lavage is continued until the choke clears or no obvious progress is being made. At that point the lavage is stopped, tube removed, and the horse is kept sedated for several hours. This allows the bolus to dissolve further, hopefully facilitating its clearance with the next try.
After resolution of the obstruction, I will often apply several gallons of water in to the stomach to help with the horse’s hydration. Depending on the severity of the choke and how the horse handled it determines whether I place the horse on antibiotics or not. Many times I err on the side of caution and go with a seven-day run of oral antibiotics. I always dispense 3-5 days of oral flunixin to help with esophageal inflammation. The horse is kept off free choice hay for 24-36 hours, and I recommend that owners slowly reintroduce hay and feed over several days. I often recommend wetting the feed or using a different feed strategy, such a slow feeder.
If a horse has choked severely enough to warrant veterinary care, I strongly recommend the owner to purchase a Prevent Feeder. The design of this feeder slows the horse from eating his feed too rapidly. He must use his lips and tongue to get the feed pellets from the cups inside. Your horse will salivate and drool, further lubricating the feed swallowed, and I think it may help to improve digestibility and performance of the feed. After an owner experiences the stress a horse goes through, the very bloody nose, the choking, and then the costs of veterinary treatment, purchasing a Prevent Feeder is a small cost and long term investment in your horse’s health.
Other preventative options include: routine dentistry by your veterinarian; isolating the horse that eats rapidly so it can relax; feeding good quality feed, free of dust and dry, loose fine particles; feeding the horse with its head down near the ground with a large feed tub; adding salt bricks as deterrents, or wetting the feed with each feeding. Dry Beet Pulp is mostly safely feed after soaking thoroughly in water; although, there are some beet pulp formulations that do not require hydration. Also, pay attention to debris in your hay. Please do not feed whole apples or carrots to your horse. Please cut them up into small pieces.
So, if your horse appears to be choking, PLEASE DO NOT PUT THE WATER HOSE OR ANYTHING LIQUID FORCEFULLY INTO YOUR HORSE’S MOUTH! Remember if your horse has feed coming out of his nostrils, the esophagus is overflowing. There is only one other opening and that would be the trachea to the lungs. I often use the analogy of repeatedly flushing a stopped up toilet; it will just make a very big mess. I have treated and euthanized horses with severe pneumonia because the owners drowned them while they were choking by forcing fluid into their mouth. That will NOT resolve the obstruction, I PROMISE! Please call your veterinarian. If your horse is calm, I often recommend waiting about an hour to see if it will resolve itself. If the horse is stressing heavily, I will get there as quickly as possible to sedate the horse.
Choke is a very frightening and sometimes a very dangerous emergency for equine patients. Most of the time with appropriate care, horses recover fine and may never choke again; but the opposite is also possible. Remember, pay attention to your horse’s eating habits, and try not to feed in small, deep, chest high feed troughs. Make sure your horses are drinking plenty of water and have good clean hay and/or pasture.
Spring time is nigh. Please have your veterinarian vaccinate your horses, at minimum, for insect-borne diseases such as West Nile Virus and Eastern/Western Encephalomyelitis, as well as Tetanus. Treat intestinal parasites based on your veterinarian’s recommendations. Remember, your horse may still have a thick winter coat. So be careful to avoid over heating your horse on those nice random warm days. Be careful and have fun!
If you have any specific equine health related questions you would like me to address, just email them to firstname.lastname@example.org. Mention if you wish to remain anonymous; otherwise, I look forward to helping you understand any health questions you may have concerning our wonderful equine companions. Thank you.
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