September 23, 2010
Certain seeds pose a significant potential threat to our dogs.
In recent years those of us who hunt and train primarily in the Midwest have seen a significant increase in problems related to grass seed awns, which until the last few years were thought of as common only in the western states. After dealing with a very serious infection last spring in one dog, last summer we had another case where one of our German shorthairs came very close to losing an eye. Our veterinarian found a Canada wild rye awn working its way behind the dog's eyeball.
Because of experiences like these, combined with what I'm hearing of the unusual increase in the number of grass awn-related problems as I travel to dog sports throughout the year, I felt it was time to give readers a heads-up on the potential hazards. To help, I've enlisted a good friend, Cathy Lewis, who recently has stepped up and taken the lead in identifying problem seeds, the disease process and treatments.
I'll first introduce Cathy, then ask her a few questions I feel you would like answered.
Cathy Lewis acquired her first field-bred English springer spaniel in 1995. She and her husband, Dean Reinke (who got his start with springers much earlier), train, field trial and occasionally breed their springers. Both are active with the ESSFTA, the springer parent club. When one of Cathy's trial springers, Tai, had recurring bouts of unexplained illness culminating in a pyothorax in 2005, Cathy was determined to find some answers about the cause.
Since then she has become much more involved, as she and Dean have dealt with four more grass awn infection cases with their own dogs as well as learning of fellow trialers' experiences. The ESSFTA established a committee to investigate the grass awn issue in 2007. Cathy was an initial member and now chairs that committee.
Bob West: Cathy, I think we should begin with an explanation of how a grass awn can cause an infection.
Cathy Lewis: Pieces of plant material, typically the awn (seed), penetrate the skin, or are inhaled or ingested as the dog runs through cover. The awns of the most problematic grasses are barbed, which allows the awn to ratchet itself along through the tissue.
The awn may carry bacteria as it enters the dog's body, and/or it may carry bacteria that are normal inhabitants of one part of the body, usually the mouth, into other parts of the body where it is abnormal, and establishes an infection, typically in the form of an abscess.
Foxtail barley, one known hazard, occurs most commonly in the western states but is now found throughout the United States . Nimblewill is another plant with potentially dangerous awns; like foxtail, nimblewill is regarded as a weed and is not purposefully cultivated. In the past few years in the Midwest and Mid-eastern regions, Canada wild rye has been implicated in a number of canine infections. 
Roz, a springer, after surgery to extract grass awn and resulting abscess. Two ribs were removed in the process and mesh was used to close the abdominal wall.
Some conservation groups have favored Canada wild rye as a low cost "cover crop" for new conservation plantings that provides nesting habitat and feed for gamebirds. Virginia wild rye is a similar plant, but with a somewhat less aggressive awn.
Foxtail awns are more commonly acquired through the skin, generally in the feet, ears or nose, thus a careful inspection of the dog after leaving the field may allow removal and avert any illness. With awns that more likely have been ingested, while a good going over after a workout never hurts, odds are that the damage has already been done by the time you and your dog leave the field.
BW: What are the symptoms of a grass awn infection?
CL: One of the major dangers of a grass awn infection is that symptoms can be very subtle until the dog is gravely ill. Knowing your dog and recognizing when he or she is "just a little off" is one of the best protections you can offer. Routinely check your dog for swellings, particularly at the lower rear sections of the ribcage, a prime site for abscess development.
The dog may cough, show a loss of stamina, and in a more advanced case involving an infection in the chest and/or lungs, may show difficulty breathing. As we have experienced these infections in our dogs I have learned to be very concerned about a temperature of around 104 degrees. This isn't necessarily high enough to alarm your veterinarian, but it's been telltale with all of our cases.
While companion dogs can be at risk, grass awn infections more typically affect working dogs. Unfortunately for many of us, our veterinarians are not necessarily up to speed on this sort of problem to where this is high up on their possibility list for differential diagnosis.
Time may be of the essence when you realize that your dog may be affected, so your dog's best chance may be you raising this as a possibility with your vet. I suggest printing out some material now and asking your vet to put it in your file so that it is readily available if it's needed .
BW: How will an infection be treated?
CL: The best piece of advice on this issue that I've received to date comes from Dr. James Mills of Searcy, AR — if you have even a remote suspicion that your dog has been exposed to hazardous plant material and your dog has symptoms with no other immediate cause, start treating the dog as though it has a grass awn infection until you can definitely determine another diagnosis.
The bacteria that create these infections are typically anaerobic, which grow in an environment without air. This complicates specimen collection and culture growth, since exposure to oxygen may prevent or retard reproduction of the bacteria in the sample; consequently culture results are often nonspecific or incomplete. Commencement of treatment should not be delayed to wait for culture reports.
In some cases ultrasound may be instructive in locating an awn or at least identifying the tract the awn creates as it travels. A chest x-ray will likely be helpful and blood work a matter of course to check for indications of infection.
Grass awns recently recovered from a Labrador.
An awn that migrates to the outside of the body and sets up an abscess may be a best-case scenario, though our experiences with this manifestation have both involved surgery.
These abscesses commonly erupt towards the rear and to the lower edge of the rib cage.
We've had two dogs with this type of symptom, and one lost the bottom few inches of the last few ribs because the abscess was both external and internal to the ribs.
The second dog had two ribs removed entirely to remove her abscess, and also lost a 1- by 3-inch piece of her back muscle, which is where the offending awn was located and removed. Apparently migration to the spinal region is also common.
An abscess or infection in the chest (pyothorax) or lung can be life threatening. Typically these cases cannot be treated with antibiotics alone; the fluid and pus in the chest cavity will need to be drained.
BW: What can you do to protect your dog?
CL: Learn to recognize hazardous plants, and be watchful of where you are hunting, training or even just exercising your dog. These plants are especially hazardous in late summer through fall as they dry out and the awns loosen and become more prone to drop. If you are in an area that may support foxtail, inspect your dog after he or she runs to remove awns before they have the chance to penetrate the skin or lodge in the ear and begin to migrate.
If you have had a dog suffer a grass awn infection, or know someone else who has, please assist in our data-gathering efforts.
Access a case history form at http://www.meanseeds.com or e-mail me at firstname.lastname@example.org.
If you are an event organizer, be aware of the problem and avoid hazardous fields.
Express your concerns to your local conservation groups. Seed mixes are available without rye grass, so be careful how you select your mix.
If you have rye grasses in your own fields, Nancy Pals, a conservation resource officer in Illinois, recommends burning to weaken the stands, and has also seen some success in reducing the amount of rye grass with overseeding with big and/or little bluestem.
BW: Thanks, Cathy. I appreciate you taking the time to update Gun Dog readers.
It's obvious you've dedicated yourself to the task, and we hope this alert will save some dogs from these hazards.
You'll find links and additional information at http://www.meanseeds.com and http://essfta.org/Health_Research/grass_awn.htm. http://www.fs.fed.us/database/feis/plants/graminoid/horjub/all.html http://plants.usda.gov/java/profile?symbol=MUSC An excellent article summarizing symptoms and treatment, Actinomycosis and Nocardiosis, Standards of Care, Volume 10, Number 3, April, 2008, can be found here: http://www.vlsstore.com/Media/PublicationsArticle/SOC_10_03_4.pdf