Can Grass Kill Your Dog?

PetMD Editorial
April 20, 2016
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By David F. Kramer

When it comes to risks to the health of our dogs, the culprits are literally all around us. While a nice walk outside is quality time for both dog and owner, it too can be fraught with potential danger. While you might be on the lookout for cars, squirrels, skunks, and porcupines, one hazard you might not be aware of is the lowly grass awn.

What is a Grass Awn? 

Whether you call them awns, mean seeds, timothy, foxtails, cheat grass, June grass, Downy Brome, or any other number of colloquial names, to dogs they generally mean one thing, and that’s trouble.

An awn is a hairy, or bristle-like, appendage growing from the ear or flower of barley, rye, and many types of widely growing grasses. The awn’s spikes and sharp edges serve a purpose—to stick and hold fast to surfaces so that they can spread their seeds to surrounding areas.

While part of the purpose of awns is to attach to passing animals and be distributed to other areas, this relationship is by no means symbiotic. Those sharp ends allow the awn to penetrate into and through the skin and tissues of a dog.

awns, dog and awn

Shown: Common wheat grass awns / Image credit: Smith Veterinary Hospital 

How Do Grass Awns Injure Dogs? 

Pretty much any contact a dog has with grass awns is potentially hazardous. Grass awns can be inhaled, become lodged in the ears, swallowed, or even just imbedded in the coat or skin. It is when they are not quickly removed by the owner, or expelled by the animal, that they become problematic.

This risk also has quite a bit to do with where you live. A leashed city dog is far less likely to come across awns, but even the most urban locales still have areas that are overgrown with all types of vegetation. So, a working dog used for tracking or hunting through the countryside might come across awns regularly, but an urban dog that spends a few moments exploring a neglected back alleyway can still be at risk.

“When I practiced in Wyoming, I saw a number of dogs with grass awns in their noses. I think the combination of lots of tall grass in the environment and dogs running off leash was to blame,” says Dr. Jennifer Coates of Fort Collins, Colorado.

“Dogs tend to ‘lead with their noses’ when they’re exploring, so it’s not too surprising that a sharp seed head from a long piece of grass might get lodged up there.”

Next: What Are the Symptoms of Grass Awn Infection?

What Are the Symptoms of Grass Awn Infection?

If a dog has an awn stuck in its nasal cavity, sneezing is usually among the first symptoms, says Dr. Coates. After a while, the problem might result in nasal drainage or infection. A dog might also excessively rub its nose.

According to Veterinarian Dr. Patrick Mahaney of California, the symptoms of a plant awn imbedding in the skin include inflammation, redness, irritation, and draining sores which have a clear or purulent (pus) discharge. He also says to be on the lookout for draining tracts (an opening through the skin surface from which the discharge drains), licking, scratching, chewing, or pawing at the site, lethargy, depression, and a decreased appetite.

How to Remove a Grass Awn from Your Dog - And When You Should Not

So, are awns something about which you should always consult your veterinarian? Well, that can be difficult to answer.

According to Dr. Coates, “If you see grass awns in your dog’s coat, remove them as quickly as possible. You can either pick them out by hand or use a brush to speed up the process.”

But removing an awn from a dog’s nose can go beyond tricky.

“An owner can attempt to remove a plant awn from their dog’s nose, but I don’t suggest doing so,” says Dr. Mahaney. “Foxtails and other plant awns typically have barbs (hooks) that firmly grasp any fabric or tissue with which they come into contact. As a result, the plant awn stays imbedded in tissue and attempts to remove the awn can lead to breakage at some point along the length of the awn and retention of the awn in the dog’s nose.”

Further explaining the danger of incomplete removal, Dr. Mahaney added that “the imbedded awn not only causes inflammation and infection at the site, but the awn generally continues to move in a forward direction and can travel great distances through body cavities from the site of imbedding.”

grass awn, awns and dog

Shown: Brittle grass awn breaking into smaller pieces / Image credit: FloridaGrasses.org

Worst Case Scenarios with Grass Awns

“Once a grass awn has penetrated through the surface layers of tissue, problems can go from bad to worse rather quickly,” says Dr. Coates. “Usually, the initial wound heals uneventfully and owners are not even aware that anything has happened, but the awn is now trapped and can start to migrate throughout the body. They can end up almost anywhere, including the lungs, the spinal cord or brain, and within abdominal organs.”

“Migrating grass awns produce infection and inflammation and disrupt normal body functions,” says Dr. Coates.

“Symptoms depend on the part of the body that is affected. I remember one case of a dog who was lame and had pus draining out of a muscle in his shoulder.” “A course of antibiotics and exploring the drainage tract for foreign material while the dog was anesthetized didn’t work,” said Dr. Coates. “Eventually, a board-certified veterinary surgeon was able to locate the grass awn and remove it, and a lot of infected and damaged muscle. The dog recovered, but only because the owner was willing to keep trying.”

Getting your pet to the vet early will greatly improve its chances for avoiding the kinds of complications that can happen when owners hope that time will heal the wound.

“When untreated, it's likely that the clinical signs of irritation and infection will worsen,” says Dr. Mahaney. Due to the potential for plant awns to travel through body tissues, there’s the likelihood that if the awn moves far enough it can enter into a body cavity and cause more severe clinical signs.”

Dr. Mahaney relates, “I’ve seen a case where a foxtail imbedded in the skin of the chest and wound its way through the intercostal muscles (between the ribs) and entered the chest cavity, causing severe inflammation, infection, pleural effusion (fluid accumulation between the lungs and the chest wall), lung collapse, and other severe secondary problems. The dog was ultimately euthanized, as the owner was not able to continue to pursue the required treatment (drainage of fluid from the chest cavity, exploratory thoracic surgery, hospitalization, laboratory testing, diagnostic imaging, etc.).”

“A plant awn that enters the nasal cavity is definitely concerning because it can potentially migrate through the nasal turbinates (scroll-like structures within the nasal passages) and butt up against cribriform plate, which is a bony structure that separates the brain from the nasal passages,” says Dr. Mahaney. “I’m not aware of the ability for a foxtail to penetrate the cribriform plate and enter the brain, but I guess one can never say never.”

Next: How to Protect Your Dog from Grass Awn Injury

How to Protect Your Dog from Grass Awn Injury

Unfortunately, owners can do only so much to protect their pets from the effects of grass awns. For working dogs, or for dogs that spend a lot of their time recreating outdoors in tall grass, there are commercially available vests that cover the chest and abdomen, as well as full head coverings. Walking dogs on a short leash to prevent them from running through tall grass also helps.

It’s wise to examine your dog after you’ve returned home from a walk or play time outside. A grooming brush can remove a tangled awn from a dog’s coat, and this is a good time to also inspect the dog’s snout, ears, and between its toes for any foreign materials. Keeping the fur between your dog’s toes trimmed will also help.

Carefully examining your dog after walks and time spent outside is the best defense against grass awns. And don’t hesitate to get your veterinarian involved if you suspect that your dog is suffering from the ill effects of coming in contact with them.

Additional Images:

grass awns, awn and dog

Shown: Grass awns illustrated, Bromus madritensis / Image credit: Stanford Jasper Ridge Biological Preserve

grass awns, oat grass, awn and dog

Shown: Common oat grass / Image credit: California’s Coastal Prairies