Mick, a three-year-old golden retriever, presented to me recently with a sudden history of lameness after spending the weekend having a wonderful time on his owner's property.
Normally a healthy, active dog, Mick became reluctant to bear weight on his left forelimb.
He wouldn't let his owners near his paw to have a look, instead choosing to sit in the corner and lick it incessantly.
When I examined a very unhappy Mick with the assistance of a gentle veterinary nurse, I found a tiny crater between his toes.
Protruding from that crater was a grass seed awn.
The surrounding fur was matted with saliva, and a little bit of pus that had discharged from the crater.
Grass seeds may look small and innocuous, but they can wreak havoc on dogs.
In Australia, the main culprits are spear grass, barley grass, wild oats and brome grass seeds.
They become caught in fur, and their sharp ends can penetrate the skin, which is itself painful.
Because they are foreign bodies, they also cause infection and inflammation, which exacerbate the pain.
Imagine having a very large splinter in the webbing between your fingers.
Mick was fortunate - the grass seed was sitting just inside the skin. I was able to remove it under local anaesthetic.
He went home with pain relief and a course of antibiotics.
But not all grass seeds stay put.
They can migrate through tissue. A grass seed that enters the skin of the paw, for example, may poke its way to another area under the skin, or even into bodily organs.
And they don't always enter by the skin.
Some dogs will inhale grass seeds as they run through grass which then may lodge in the nasal cavity or the lungs.
A dog belonging to a colleague of mine recently underwent a lung lobe removal to treat a life-threatening infection caused by a grass seed.
They also commonly lodge in the ears of dogs. Affected dogs may shake their heads, scratch their ears and be very reactive if touched around the head area.
Retrieval of grass seeds from canine ears usually requires a general anaesthetic, and in some case the use of a video-otoscope introduced into the ear canal so that the grass seed can be seen and retrieved.
According to an Australian study, grass seed foreign bodies comprised two per cent of all canine hospital admissions in southwest rural New South Wales.
Working dogs and breeds with thick coats, including border collies, shih tzus and spaniels, were more commonly affected.
Almost half of cases involved one or more grass seeds found inside the ear canal of affected dogs. In a small number of cases, grass seeds migrated from the ear canal into the brain, causing severe brain disease.
Finding a grass seed isn't always as easy as it was with Mick. I've gone hunting for grass seeds in similar craters in anaesthetised dogs, and turned up nothing.
Every veterinarian can tell you a similar tale.
Sometimes we need to employ contrast radiology, ultrasound, endoscopy, even advanced imaging like CT and MRI to locate a very problematic grass seed.
The study found that weekly grooming of dogs helped protect against grass seed foreign bodies.
In addition to this, searching the coat of dogs that have been exercising in grass, and removing grass seeds immediately, may help.
Once Mick's paw healed, his owners took him to the groomer to trim his long fur.
He still gets to run around in the country, but he is checked for grass seeds daily.
Reference: Hicks, A.; Golland, D.; Heller, J.; Malik, R.; Combs, M. Epidemiological investigation of grass seed foreign body-related disease in dogs of the Riverina district of rural Australia. Australian Veterinary Journal 2016, 94, 67-75.
Dr Anne Quainis a lecturer at the Sydney School of Veterinary Science and a practising veterinarian.