Why Can’t a Horse Throw Up?

 

It’s true; horse vomit is not a thing. This equine quirk can create many digestive problems and emergencies. Subsequently, this gives the horse owner one more thing to be aware of regarding their horse’s digestive health and colic episodes. Why can’t a horse throw up? It’s primarily anatomy-related and also related to a horse’s gaits.

 

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The Equine Digestive System

 

• The horse’s digestive system is a long series of questionably designed organs that somehow transform hay and feed into manure. This journey begins in the horse’s mouth, where strong teeth that never stop growing mix with saliva to kick off digestion. It then goes down the esophagus and into the stomach. In the relatively tiny stomach’s mixing bowl, chewed food meets enzymes and acids and passes into the small intestine, where most nutrients are absorbed.

 

• The remaining roughage enters the cecum for fermentation by microbes. Interestingly enough, the entrance and exit to the cecum are in the same location! What’s left hits the large colon to absorb water and some nutrients. Finally, the small colon forms fecal balls stored in the rectum until your horse passes manure and gives you more chores.

 

For more fun facts about the equine digestive system, read this.

 

When horses run, their bodies shift forward, expelling air.  What would happen if they could vomit? 

 

Why Can’t a Horse Throw Up? It’s Anatomy

 

• The equine stomach is the primary reason a horse won’t throw up. As food moves from the esophagus into the stomach, it passes through the cardiac sphincter. This sphincter is the bodybuilding champion of sphincters and won’t budge the other way. It’s a one-way street, with no exceptions.

 

• Another reason food travels one way to the stomach is the esophagus muscles. These muscles create a moving walkway, known as peristalsis, for chewed food to enter the stomach. Unlike in other animals, peristalsis is one-way in horses.

 

• The third reason horses can’t vomit is the angle of the esophagus in relation to the stomach. The esophagus descends steeply into the stomach, and if something happens there, the contents push upwards, further strengthening the cardiac sphincter.

 

• Lastly, horses don’t have a gag reflex that assists with vomiting.

 

When horses run

 

• Horses are bizarre creatures, and one instance of this occurs at the canter and gallop. As horses run, the action of their rear legs coming forward and their bellies contracting creates an exhale. This is why you can hear a horse breathing the canter rhythm. It’s a lot of force to move air out of the lungs.

 

• This same force also pushes the abdomen forward. If a horse’s cardiac sphincter and stomach anatomy didn’t prevent vomiting, we might have a creature that throws up with every stride.

 

Horses rolling may mean normal behavior, or colic.  Either way, they are not vomiting. 

 

The Physiology of Vomiting

 

• The vomiting process happens when your brain, stomach, esophagus, larynx, and abdomen all work together to expel stomach contents. This protective mechanism is a response to harmful situations or dangerous stomach contents.

 

• If the stomach and intestines are in distress, let’s say from food poisoning, the brain tells the rest of the body to become a bulldozer and get rid of its contents. The diaphragm and abdominal muscles contract to increase pressure. The stomach muscles relax, allowing their contents to move, and since the abs are squishing, the contents can only go up. As that happens, the larynx rises, the soft palate shifts, and the lower esophageal sphincter between the esophagus and stomach opens. Hence, throwing up.

 

But…horses

 

• The big problem with horses not vomiting is the lack of relief from gas, toxins, and any other reason the digestive system needs to expel its contents. So, when humans are “colicky” with digestive issues, we can vomit for relief. Horses don’t have this luxury, which can make colic episodes dangerous, even to the point of a ruptured stomach.

 

Horses can become quite ill from acorns. 

 

What would make a horse need to vomit?

 

• How would a stomach rupture or tragic colic even happen? It’s largely related to a horse’s eating habits and food options.

 

• High-sugar and high-starch feeds can trigger excessive gas. This chain reaction process in the cecum also creates dangerous endotoxins linked to laminitis in horses.

 

• Overeating is another culprit, simply creating a traffic jam of food in the stomach. The cliche “broke into the feed room” situation is dangerous, regardless of how much your horse enjoys it.

 

• When a horse ingests toxins, which is rare, vomiting would undoubtedly help. Most horses are savvy enough to avoid eating toxic plants, but grazing on them is possible if they are desperate for food. Also, not all poisonous plants taste terrible – some are quite delicious, like acorns and maple leaves.

 

• And the quality of hay and feed you provide is critical, too. Toxins exist in moldy hay and feeds, and blister beetles in alfalfa are deadly.

 

For more on acorns, read this.

Read about the dangers of maple trees and leaves here.

This article about blister beetles will have you inspecting hay with a magnifying glass.

 

Maple leaves are a big no-no.

 

Choke vs. Vomiting

 

• Choke in horses can look a lot like vomiting, but it’s not the same! When a bolus of food gets lodged in the esophagus, it’s choke, which in humans happens in the respiratory system.

 

• For horses, this means the traffic jam is before the stomach. Saliva, water, mucus, and food material will back up the esophagus and drip out of the nose and mouth. At first glance, this sure looks like horse vomit. But it’s not.

 

• Choke is a dangerous veterinary emergency, and severe cases can result in aspiration pneumonia if your horse accidentally inhales any of the drips. If it looks like horse throw up, or if your horse could benefit from throwing up (even though they can’t), it’s probably choke.

 

Read this for more information about choke.

 

Signs of Digestive Distress and Problems in Horses

 

• Sometimes, horses will shout out to the universe that they have colic. Others prefer to send coded messages without a key. Here are some things to consider when monitoring your horse’s digestive health.

 

• Signs of digestive problems:

 

• • • Lying down and getting up repeatedly
    • Belly kicking due to abdominal pain
    • Flehmen response
    • Sweating
    • Stiff neck (seen in choke)
    • Drooling out of nostrils or mouth (also choke)
    • Odd or absent gut sounds
    • Distress, pacing, pawing, weird behavior
    • Diarrhea
    • Tiny, hard fecal balls
    • Frequent urination of small amounts
    • Not eating or drinking
    • Increased pulse and respiratory rates

 

• Generally, any sign of distress warrants a call to your vet before you give meds. Many things look like colic, and giving meds can mask essential clues about your horse’s health when your vet arrives. Your vet should also be your first call, as extreme digestive disturbances often look mild and vice versa.

 

Read all about the signs of colic here.

 

Can you “read” your horse’s manure? 

 

Preventative Measures for Maintaining Equine Gut Health

 

Prevention is crucial for so many aspects of horse health, and there is plenty we can do. Here are some top tips for equine gut goodness:

Water

 

• Not only do horses need fresh water, but we also need to monitor how much they drink and whether their bodies are hydrated. There are various measuring devices for automatic waterers, some included and some after-market. To watch for dehydration, check your horse’s gums. Their mouths contain so much information about overall health.

 

Use slow feeders

 

• There are dozens of ways to slow-feed hay in all forms. You can find slow-feeding systems for bales, round bales, pellets, cubes; you name it. The same slow feeders for pellets are amazing at feeding “grains” and commercial feeds, too.

 

• Feed your horse smaller “meals” more frequently. If they need 4 lbs. of feed daily, give them more than one feeding in very small portions. This reduces the volume of food zipping through their digestive tract and into the hindgut for fermentation, where the sugars and starches can create problems.

 

Grazing muzzles are slow feeders! 

 

 

Grazing muzzles are slow feeders

 

• Pasture is a privilege for many owners and their equine friend, but it can quickly create colic and laminitis in higher-risk horses or if it’s a new part of the diet. Grazing muzzles are wearable slow feeders. That is all!

 

Make diet changes slowly

 

• Any time you introduce a new feed, supplement, or pasture situation, it takes about two weeks to transition your horse safely. This process should include decreasing the previous feed and slowly increasing the new feed. For grazing situations, use muzzles. Every horse is going to go fast when unfettered access to salad is permitted.

 

Know your horse’s metabolic status.

 

• Your vet can easily test for PPID (Cushing’s disease) and equine metabolic syndrome, which includes insulin resistance. These tests help indicate laminitis and colic risk.

 

Keep your horse a healthy weight

 

• A simple horse weight tape lets you track your horse’s weight over time. Overweight horses are at higher risk of overheating, metabolic disorders, arthritis, and hoof problems. Every few weeks, measure and log to look for trends over time.

 

Keep a tidy feed room

 

• Store commercial feeds properly in sealed containers. Do your best to keep rodents out and keep ventilation flowing. Store hay off the ground with plenty of air between the earth and the hay.

 

Use appropriate supplements that support digestive health

 

• Many equine supplements keep your horse on track. Omega-3 fatty acids are great for overall health because of their anti-inflammatory properties. Your horse may also benefit from prebiotics, probiotics, ulcer medications, a hindgut buffer, or additional fiber.

 

Read this for more about your horse’s gums.

Get the scoop on when to use grazing muzzles here.

 

Weird behaviors are a sign that something is wrong. 

 

Can other animals besides horses vomit?

 

Different species of animals, including rats, rabbits, guinea pigs, and other rodents, are unable to vomit. They do not have the vomiting reflex. Horses are certainly not alone with this special skill or lack of skill.

 

 

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