It's not a new fad and probably isn't what you're thinking. Horses sometimes accidentally become wounded by pieces of metal or wire, splinters of wood, or even grass awns that become lodged in their tongue, mouth, or throat as they eat. These and other foreign bodies can cause serious medical problems and great discomfort for a horse within hours or days of the puncture.

"Within 24 to 48 hours, owners usually begin to notice that their horse is painful and won't eat," said Macarena Sanz, DVM, a Washington State University (WSU) third-year equine medicine resident. "The horse may also have increased salivation, a swollen tongue or cheeks, and bad breath.

"A lot of owners think the problem is caused from an insect bite or sting, but it is more likely from a foreign body that got lodged in the mouth," she said. "If the problem was caused by an insect, such as a bee, fly, or spider like a black widow or brown recluse, the swelling should decrease with time. The same is true of mild lacerations. If a foreign body is the culprit, the swelling will remain or even get worse after two or three days. Until it is removed, the problem will not go away."

Because horses have to eat, and some have an affinity for chewing on things like wooden fences, it can be hard to prevent a horse from getting a splinter or pierced with a foreign object. But many cases can be traced to a few sources that are preventable.

radiograph of horse's skull with wire in tongue
wire removed from horse's tongue

Top: A radiograph of a lateral view of a horse's skull with a wire in its intermandibular space. Bottom: The wire shown above after it was removed.

Horses with metallic splinters are often stuck when eating out of tractor tires that were cut in two and converted to feeding troughs. Hay containing problematic grass awns from species such as bristle grass or foxtail grasses (Setaria spp.), wild barley and foxtail barley (Hordeum spp.), and needlegrass (Stipa spp.) is another source for blisters, lesions and ulcerations in a horse's mouth.

"Mechanical irritation and sores from grass awns are completely preventable," said Patricia Talcott, DVM, PhD, Dipl. ABVT, a WSU associate professor who provides diagnostic toxicology services for the Washington Animal Disease Diagnostic Laboratory (WADDL) in Pullman.

"It is important for owners to know what they are purchasing when buying hay, and to be able to recognize components in the hay they feed," Talcott said. "If owners have questions about what is in their hay, county extension services are very useful and can help identify which grasses are present."

Owners that notice their horse has a swollen mouth might attempt to administer anti-inflammatory drugs such as phenylbutazone (Bute) or flunixin meglumine (Banamine), however, Sanz cautions against doing so in these cases.

"When you have a horse with a swollen mouth or tongue, you must be very careful when administering anti-inflammatories or some antibiotics if the horse is not drinking," Sanz said. "These drugs (phenylbutazone and flunixin meglumine) can be very hard on the horse's kidneys if they are not drinking enough water, and can cause severe kidney damage. These drugs should be administered if indicated by a veterinarian so the dose and frequency of administration are correct."

If the swelling remains after a couple of days, it is important to seek veterinary attention as the object usually requires surgical removal. Pain, dehydration, anorexia, infections and other associated problems are also cause for concern.

Unfortunately, the offending object can be hard to diagnose because often it is buried in soft tissue that becomes swollen.

"Many objects like wood are hard to diagnose and find, but metallic objects are easier because they show up more clearly on a radiograph or X ray," Sanz said.

At the WSU Veterinary Teaching Hospital, horses with swollen mouths or tongues are sedated and receive an oral exam to check for wire and other objects.

"Sometimes, a bad tooth can cause similar symptoms, especially if material is not found in the tongue," Sanz said. "If the material is not found during the oral examination, radiographs or ultrasound imaging are used in attempt to diagnose the problem."

When the object is located, the horse is sedated, the area is blocked with a local anesthetic, and the material is removed. If the object is in a complicated area, such as the throat, the horse is put under general anesthesia before it is removed.

"After we remove the object, the horse is put on antibiotics for three to five days because most of the time an abscess forms around the foreign body," Sanz said. "The abscess usually drains when the object is taken out and we don't suture the incision closed because we want to let it continually drain and heal from the inside out."

In addition to antibiotics, anti-inflammatory drugs are also administered as needed, and the incision is cleaned for five to seven days.

Sanz said affected horses can stay at the veterinary teaching hospital during recovery, or might be able to go home, depending on how comfortable the owner is with the post-surgical care.

Horse owners in the Washington area who have an animal with a swollen mouth or tongue, can contact the WSU Veterinary Teaching Hospital at 509/335-0711 for an appointment or emergency.

Hay and plant samples can also be sent to Talcott at WADDL for identification. For more information, contact her at 509/335-9696.

Reprinted from the WSU College of Veterinary Medicine Equine News Summer 2008 issue.

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