Because I'm from the US I wasn't quite sure what 'grass seeds' were until someone said they get stuck in the pasterns and mouths of horses and cause ulcerations. Especially this time of the year over in Tasmania. ICK! ... but that led me to realize that "grass seeds" is probably the same thing as we Americans call "Foxtail Grass" (Setaria species).
Although there are a couple of other grasses that are similar ... Sandbur (Cenchrus species) and Ticklegrass (Agrostis hyemalis) the Foxtail seems to be a huge culprit of mouth and heel/pastern ulcerations.
It's just nasty stuff.
Foxtail's cousins are often known as cheat grass, grass awns, june grass or downy brome.
Now, if I'm wrong about the type of grass, then please, feel free to correct me and then educate me! I realize there are different vegetations all over the world but my little world only encompasses the US. These are the grasses, however, that seem to be the most prevalant across many regions of the world.
That being said, let's take a look at why this grass is so nasty and what can be done when/if you encounter a seed bur solidly embedded in the horse's pastern or heel and how you can treat it safely.
"Jennie Ivey, University of Tennessee Extension Equine Specialist, says foxtail does not produce a chemical toxin dangerous to horses, but rather the structure of the plant itself can cause physical harm. “Microscopic barbs on the seed heads of stems of foxtail can cause physical trauma to the mouth leading to mouth blisters, irritation to the gastrointestinal tract, and occasionally the horse’s skin,” Ivey states. The leaves do not cause trauma and can be consumed, but are not recommended forage sources for horses."
Foxtail grass is an annual that reproduces through fallen seed. It is not a perennial. Judging from the patch of it in my back area up north, tho, it reproduces profusely! In just two years it had tripled its area that it took up. Thankfully it wasn't in an area to which to horses could reach. The seeds have little sticky spikes on them that will stick into the soft flesh of mouths and feet. Because the grass grows to five feet or taller, the barbed seeds can also get into the horse's nose and even in his eyes and ears. It's easy for horses to catch these seeds on their pasterns and heel bulb areas where the awns can go unnoticed until there is an open sore that is discovered where the seed has worked its way into the flesh. The horse will probably be a bit tender. What I would do in this case would be to soak the hoof a couple times a day in some activated charcoal water then apply a poultice using lavender and melaleuca essential oils mixed with some raw honey and zinc to help soothe, protect and draw out the awn. I would also use homeopathic remedies to complement the poulticing.
Alternatively, if you have any concerns about infection in the hoof, it is always best to consult your veterinarian or professional health care practitioner. Surgery may be required to extract the awn and fully treat the resulting infection and wound.
Unfortunately, Foxtail and its cousins can also be dried in hays. Close inspection of the hay must always be given in order to avoid any mouth and gum insults from the grass seed. If any hay shows inclusion of the grass seed then I would dispose of the entire bale without thinking of feeding it. It's just not worth the risk of mouth ulcerations from embedded awns. Below are some more photos of the Foxtail and its cousins:
So, if you've been out trail riding and your horse is in otherwise good, sound condition but you notice sores on the heels, fetlock or pastern OR ... you find that there are sores in your horse's mouth or ears, please inspect them and suspect that he might have gotten into some Foxtail or one of its cousins. Daily grooming and inspection will help to alleviate any advancement of wounds if they are caught early on.
Gwenyth Browning Jones Santagate is the best-selling author of 10 Secrets to Healthy Hooves as well as a noted author for various international equine publications includingThe Horses Hoof, Equine Wellness, Natural Horse Planet as well as a contributing author for the 2001 United States Federal Mounted Border Patrol Training Manual. For the last 37+ years, she has maintained healthy hooves with natural trimming on thousands of horses and specialized in pathological rehabilitation hoofcare for the last 18 years. She and her husband John keep a small herd of their own equine in SW Florida and continue to offer consults for horses in need. For further information please click here: www.thepenzancehorse.com/2012/RESUME.pdf