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Oral Ulcers in Horses: Symptoms, Causes, and Cures

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Since I was a little girl my passion, after writing, has been horses. Learning and sharing everything I know with you here. Happy Trails!

Here's a good example of a horse's oral ulcer. If you look closely, you can still see some of the foxtails are still sticking out.

Here's a good example of a horse's oral ulcer. If you look closely, you can still see some of the foxtails are still sticking out.

Symptoms of Mouth Ulcers in Horses

If you are concerned that your horse may have oral ulcers, there are clear symptoms to look for.

  • Your horse is interested at feeding time, yet stops eating soon after he starts.
  • The horse's mouth hangs slightly open or the lower lip hangs down.
  • A very common symptom is drooling!
  • Small piles of uneaten feed near the feeding area.
  • The mouth and/or lips are sensitive to touch.
  • You can see visible ulcers inside the mouth, especially along the lower lip canal.
  • Beyond these listed symptoms, you should have a thorough look at the hay your horse is eating. Sometimes you can find the culprit in their hay.

Which Weeds and Grasses Are Dangerous for Horses?

These are the symptoms of ulcers caused by undesirable grasses in hay. When the hay being fed to your horse has an overabundance of undesirable grasses, your horse will develop red, open ulcers in his mouth. These open ulcers will often have the culprit weeds still embedded in them.

Ripgut (Bromus diandrus), foxtail (Hordeum murinum), and cheatgrass (Bromus tektorum) are just a few common and extremely problematic grasses within the US. There are too many varieties of undesirable grasses to list them all, but these are the most notorious ones, especially the Ripgut, which can even perforate a cow's gut.

Note: The Ripgut grass was the culprit in our situation, so the photos and videos you find in this article are of that grass.

Ripgut, Foxtail, Cheatgrass Distribution


Why Intervention Is Required

A horse cannot remove these undesirable grasses from their mouth. These grasses have spines on them pointing in one direction: in. When their feed has a lot of them, they build up in the lower lip, piercing the tender flesh, embedding themselves in their lip. Once one has penetrated the flesh, it's really easy for more to pile into the hole. One after another, as the horse picks up his hay with his lips, the undesirable grasses drop off their spiny arrows, that in turn, they embed themselves into his lips.

The horse will continue to eat until he is in so much discomfort he cannot pick up another mouthful of the hay. At this point, it is too painful to hold his lips together and swallow his saliva. He will then stop eating, stand with his lips apart, drooling profusely. The drool will sometimes extend from his lip all the way to the ground.

Photo of a sore in a horse's mouth caused by foxtail.

Photo of a sore in a horse's mouth caused by foxtail.

Know Your Foxtail Grasses!

Type of GrassSeasonCommonly Found

Foxtail or Wild Barley (Hordeum Murinum)

Springtime: Green and supple. Summer: Dry and brittle.

Roads, paths, "weedy" areas

Ripgut Grass (Bromus Diandrus)

Springtime: Green and somewhat supple. Summer: Dry, dangerous for animals if ingested.

Grassy Hillsides

Cheatgrass (Bromus Tektorum)

Same as Ripgut; Sprintime: Green and somewhat supple. Summer: Dry, but not as dangerous as ripgut grass.

Grassy Hillsides, desert areas

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How to Prevent Oral Ulcers Caused by Grasses

You can be a diligent horse (or any grass-eating animal) owner and pay attention to what is fed to him. These grasses start growing in the early spring. They are soft and supple at this time, but as the summer months dry out the grasses, they become dangerous. If you identify and pull out the dangerous grasses, you will be able to avoid or reduce your animal's exposure to them.

How to Check and Treat Your Horse for Oral Ulcers

When you notice your horse is exhibiting these symptoms, you need to take action to identify and relieve his pain. Some horses don't mind having a person touch their mouths, but others aren't as easy. Patience is the key here. Even the most docile horse in the barn can become resistant when human fingers are probing his tender mouth full of stickers—it hurts!

  1. Have someone help you; it's just easier that way.
  2. Put a halter on him so he can't walk away before you're done.
  3. Gently put your thumb into the corner of his lower lip and slide it down until you can lift the lip away from the teeth. His natural saliva will help with sliding your finger.
  4. Don't put your finger between the teeth at or beyond the occlusion, or you may very well be accidentally bitten.
  5. Now that you have the lip pulled down, look closely at the ulcers. Are there little white or yellow things sticking out of them or lying in them? These are the undesirable grasses like foxtails, ripgut, and cheatgrass embedded into the ulcer.
  6. With tweezers or your bare fingers, pull them out. Keep picking them out until you can't see any more.
  7. Check the front of his mouth and the other side. If one side has an ulcer, the other side probably does too.
  8. After you have picked it all out, prepare a bottle of warm saltwater and spray it gently into his mouth on the sores. This will help with the healing process.

Alfalfa Cubes

I've used alfalfa cubes successfully. They provide all the nutrients of alfalfa, and some brands even have added nutrients. Alfalfa cubes are especially helpful if you have to feed in a windy area. They won't blow away as alfalfa flakes do. I will wet the cubes before feeding them to the horses and make sure the horses have plenty of water.

Photo of a sore in a horse's mouth caused by foxtail grass.

Photo of a sore in a horse's mouth caused by foxtail grass.

If you find an ulcer on one side of the horse's mouth, you're likely to find them on the other side, too.

If you find an ulcer on one side of the horse's mouth, you're likely to find them on the other side, too.

Can You Identify the Foxtail?

Horses are very resilient, especially with oral problems. Don't be surprised if you check the next day and the sores are halfway healed or more! If you find they are not healing by week's end, then there may be a stubborn foxtail embedded or another issue that needs veterinarian attention.

The short video below shows how to open a horse's lips. It also includes still shots of the ulcers at the end of the video.

Short Video of Ulcers in the Mouth

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

© 2013 Joanna

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