By: Dr. Angela Mackay
Swift action is key when your horse is choking.
I’ve treated many episodes of choke as a veterinarian, but the first time I saw a horse choking was when I was 14 years old. My pony Miko got out of her pasture and found the bin of dried beet pulp that was stored in the barn. She had previously been a rescue horse, so she was very food motivated and would eat all manner of things including peanut butter sandwiches.
We found her choking with an esophageal obstruction, and it was very difficult to resolve. After about two hours of lavage and medications, our veterinarian finally got the obstruction cleared. After that, we made sure to fix the pasture fence so Miko couldn’t escape again.
What is choke?
Choke in horses refers to an esophageal obstruction. While this condition is considered an emergency, it’s not immediately life-threatening. A choking horse is still able to breathe because the anatomy of the trachea (or windpipe, which leads to the lungs) and esophagus (the muscular tube which goes from the mouth to the stomach) is slightly different in horses than it is in humans.
When both horses and humans swallow their food, the larynx covers the opening to the trachea to ensure that food travels down the esophagus and not the windpipe. Since we can breathe through our noses and mouths, food can get sucked into our windpipes if we try to breathe and swallow at the same time and our larynx doesn’t completely cover the trachea.
Horses are obligate nasal breathers – they can only inhale air through their nostrils. Unless something changes how their larynx works, they’re functionally quite good at protecting their airway. But horses do have a very long esophagus, which makes them susceptible to having lumps of food or foreign material sticking at some point on the way to the stomach.
What are the signs?
The most common clinical sign is nasal discharge containing feed material. Most horses tend to be very anxious; they might look like they’re chewing or trying to swallow repeatedly. Other signs include standing with the head and neck stretched out, and drooling.
When should you call the vet?
It’s best to call your veterinarian right away. While some horses can pass the choke on their own, it’s always safest to seek advice. You may not know how long a choke has been going on, and a veterinarian can help determine if immediate treatment is needed.
If a horse has nasal discharge with feed material in it, a veterinarian should always examine that patient. The feed material may also have travelled down the trachea and contaminated the lungs, which could cause pneumonia.
While waiting for the vet to arrive, remove all food and water from the stall or from the horse’s reach. Try to keep the horse calm. Some may recommend leaving water in the stall so the horse can try to drink and soften the obstruction on its own, but if the obstruction is severe, water and food material may go into the trachea.
How is it treated?
The horse is first treated with a sedative, which will help relax the esophagus and the horse. Additional medication to relax the smooth muscle of the esophagus may be given. In most cases, the veterinarians will pass a nasogastric tube down the esophagus in an attempt to reach the stomach. If an obstruction is met before reaching the stomach, the veterinarian will try to dislodge it using gentle lavage (passing water down the tube). During this procedure, it’s imperative that the horse be relaxed with its head down to prevent any dislodged material from flowing back into the trachea.
Obstructions that are more difficult to remove might get a referral to a veterinary referral centre for supportive intravenous fluids and/or an endoscopy that will enable veterinarians to try and get a look at the blockage. Surgery is an option in severe cases, but this treatment carries a poor prognosis.
If your horse has recently choked, your veterinarian will likely recommend soaking his feed for a period of time to increase water intake and decrease the risk of repeat choke episodes while he heals.
Are there potential complications?
Aspiration pneumonia from inhalation of food particles is one of the main concerns. Antibiotics will often be prescribed following resolution of the choke since a low-grade pneumonia will often occur. If severe pneumonia develops, a veterinarian will refer the patient to a veterinary hospital for monitoring and more intensive treatment.
Esophageal injury causing stricture (narrowing of the esophagus) and/or scarring can lead to a higher likelihood of recurrent choke episodes. Horses with neurological problems or trauma-related damage to the nerves that supply the esophagus can have permanent difficulty in swallowing.
In severe cases, esophageal rupture may occur, which has a guarded to poor prognosis. The horse would need a complicated surgery to repair the rupture, and recovery can be difficult and long lasting.
How can it be prevented?
• Ensure horses have access to an adequate source of good quality water.
• Always soak beet pulp pellets and allow them to expand before feeding. Do not feed dry beet pulp. If feeding other pelleted feeds, sweet feed or hay cubes, adding water can soften the feed, help prevent obstruction and encourage horses to eat more slowly.
• Keep feed securely locked away so your herd’s equine Houdini can’t escape and make a meal of dry beet pulp, or other feed such as oats, which can cause laminitis and colic.
• Slow eaters that feel threatened by the presence of herd mates may bolt their feed (swallow quickly without adequate chewing). Ensure a safe and relaxed feeding environment for all horses.
• For horses fed alone, placing rocks in their feed tub or spreading out their feed in several places can force them to eat more slowly.
• Allow horses adequate recovery time without access to food after they’ve been sedated for routine veterinary work.
• Maintain good dental health so horses can chew properly, especially older horses.
• Do not allow horses to chew or ingest any foreign material.