Foxtail grass is a common wild plant found across North America, often appearing in fields, along roadsides, and in unmaintained lawns. The name “foxtail” refers to grasses from several genera, including Setaria and Hordeum, which produce characteristic bushy seed heads. The danger this plant poses to animals is not due to toxicity; rather, it is a severe mechanical hazard caused by its mature seed structures. These dried seed heads, known as awns, are barbed and needle-sharp, allowing them to penetrate soft tissue with ease. Once embedded, the awns cannot naturally be expelled and can migrate through an animal’s body, leading to serious infections and damage.
Identifying Foxtail Grass and Its Dangerous Structure
Foxtail grass is recognized by its seed head, which often resembles a fox’s tail or a small, bristly head of wheat, typically growing one to three feet tall. In the spring and early summer, these seed heads are soft and green. As they mature, they dry out, harden, and become brittle, which is when the plant is most hazardous because the cluster breaks apart into individual barbed seeds.
The awn is designed for one-way movement. Each awn possesses microscopic, backward-facing barbs along its length, similar to a fishhook. This design allows the awn to easily penetrate an animal’s skin or orifice and then prevents it from backing out. Any muscular movement by the animal, such as walking or coughing, acts to ratchet the awn deeper into the tissue.
Animals That Consume Foxtail Foliage
Foxtail grasses are grazed by various animals, including livestock like cattle, sheep, and horses, as well as certain wildlife species. These grazing animals generally consume the plant when it is young and green, before the hazardous seed heads have fully developed. When eaten in this immature state, the foliage itself is usually not toxic, though it has relatively poor nutritional value compared to high-quality forage.
If mature, dried foxtail seed heads are consumed, they can lodge in an animal’s mouth, causing physical trauma. The sharp awns can embed in the tongue, gums, or throat, leading to painful mouth ulcers, lesions, and decreased feed intake. Inspecting hay for mature foxtail awns is a recommended practice for owners of grazing animals to mitigate this risk.
How Foxtail Awns Cause Internal Harm
The barbed foxtail awns can enter an animal’s body through nearly any opening or by piercing the skin, creating a severe internal foreign body problem. Common entry points include the spaces between the toes of a paw, the ear canal, the nostrils, and the eyes. Once inside, the microscopic barbs prevent the body from expelling the awn, and muscle movement drives it deeper into soft tissue.
The awns carry bacteria and can migrate throughout the body, causing chronic inflammation, abscesses, and widespread infection. Awns inhaled through the nose can travel into the respiratory tract, potentially causing severe pneumonia or migrating into the thoracic cavity, leading to pyothorax (a life-threatening accumulation of pus).
In extreme cases, awns have migrated from the lungs, through the diaphragm, and into the abdominal space, causing septic reactions in distant organs. A foxtail that enters the paw can travel up a limb, causing a draining tract and extensive tissue damage that is difficult to locate and remove.
Recognizing Symptoms and Immediate Action
Identifying a foxtail infestation requires observing specific behavioral changes in the animal, which are dependent on the point of entry. An awn lodged in the ear will often cause persistent head shaking, head tilting, or frantic scratching. If the awn entered through the nose, the animal may experience intense sneezing, pawing at the face, or a discharge from one nostril.
A foxtail embedded in the skin, particularly between the toes, may manifest as swelling, a non-healing wound, or a painful lump that the animal obsessively licks or chews. If an awn is suspected near the eye, symptoms include squinting, redness, or discharge, requiring immediate attention to prevent ocular damage.
Because these awns continuously migrate inward, they will not resolve on their own, making prompt veterinary intervention necessary. Professional removal, often requiring specialized tools like an endoscope or surgical exploration under anesthesia, is the only definitive treatment to prevent further migration and severe complications.