Foxtail in Hay: A Hidden Danger for Horses

Foxtail is a common grass that can pose serious health problems for horses when it finds its way into hay or pasture. While it might look harmless, foxtail seed heads can cause painful sores and irritation in a horse’s mouth, lips, and digestive tract. Recognising and preventing foxtail contamination in hay is an important part of keeping your horse healthy and comfortable, especially through the winter months when hay is the main feed source.

This article explains what foxtail is, how it affects horses, the signs to watch for, and how to prevent and manage foxtail contamination in your horse’s diet.

What Is Foxtail?

Foxtail is a general term for several types of grasses that produce bristly seed heads resembling a fox’s tail. The most common species that affect horses include:

• Green foxtail (Setaria viridis)
• Yellow foxtail (Setaria pumila)
• Giant foxtail (Setaria faberi)
• Foxtail barley (Hordeum jubatum)

These grasses are common in hayfields, pastures, and along roadsides. When they mature, their seed heads form clusters of sharp, barbed awns (hairs or bristles). While young foxtail plants are soft and palatable, once they dry out, the seed heads become stiff and spiky, posing a risk to any animal that eats them.

Why Foxtail Is Dangerous to Horses

The danger of foxtail lies in its awn, the stiff bristle attached to the seed. These awns are designed by nature to help the plant’s seeds stick to animals and spread, but in horses they can cause severe irritation or injury.

When a horse eats hay containing foxtail seed heads, the sharp awns can embed in soft tissues such as:

• Lips and muzzle
• Gums and tongue
• Cheeks and palate
• Throat and oesophagus

The barbed structure makes them difficult to remove and causes inflammation, ulcers, and infection. In some cases, the horse may also ingest awns that irritate the stomach and intestines.

Common Signs of Foxtail Injury

Because the symptoms resemble other mouth or feed-related issues, foxtail injuries can sometimes go unnoticed. Watch for the following signs:

• Reluctance to eat or chew hay
• Dropping partially chewed feed (quidding)
• Excessive drooling or foamy saliva
• Swelling or sores on the lips, tongue, or gums
• Pawing at the mouth or rubbing the muzzle on objects
• Sudden resistance to the bit or bridle
• Weight loss or reduced appetite
• Signs of discomfort when eating coarse feed

On inspection, you may notice small yellowish bristles embedded in the lips or gums, or ulcers caused by irritation from the seed heads.

Diagnosing Foxtail Problems

If your horse shows any of the symptoms above, it’s important to have a veterinarian perform an oral examination. Using a light and mouth speculum, the vet can inspect all areas of the mouth and remove any embedded awns. In severe cases, a topical anaesthetic may be needed to allow thorough cleaning and treatment.

A sample of the hay can also be examined to confirm foxtail contamination. Identifying the source helps prevent future exposure.

Treatment

Treatment focuses on removing the irritants and soothing the damaged tissues.

1. Physical Removal

All visible foxtail awns must be carefully removed from the mouth and surrounding tissues. This may require sedation or local anaesthesia if the horse is in pain.

2. Anti-Inflammatory and Pain Relief

Your vet may prescribe anti-inflammatory drugs such as phenylbutazone or flunixin meglumine to reduce swelling and discomfort.

3. Antiseptic Rinses and Wound Care

Rinsing the mouth with warm saline or an antiseptic solution (such as diluted chlorhexidine) helps clean the area and promote healing.

4. Soft Feed

Feed soft mashes or soaked pellets until the horse’s mouth has healed, avoiding hay or coarse roughage that could worsen the irritation.

5. Antibiotics (if needed)

If secondary bacterial infection develops, antibiotic treatment may be prescribed.

With prompt care, most horses recover fully once the foxtail awns are removed and the irritation subsides.

Preventing Foxtail Contamination

Prevention is far better than treatment when it comes to foxtail. Careful hay selection and pasture management are the best defences.

1. Inspect Hay Before Purchase

Examine hay bales closely for seed heads or bristly material. Foxtail seed heads are often light green to golden brown and have a fuzzy, spiked appearance. Rub a handful between your fingers, if it feels sharp or prickly, it may contain foxtail.

2. Buy from Trusted Sources

Purchase hay from reputable suppliers who manage their fields carefully and cut hay before weeds mature and go to seed.

3. Manage Pastures

• Mow or spray to control foxtail before seed heads develop.
• Avoid overgrazing, which allows weeds like foxtail to take over.
• Rotate grazing areas and reseed with quality forage grasses if foxtail becomes established.

4. Store Hay Properly

Store hay in a clean, dry area to prevent contamination from wild grasses that may grow near storage barns or paddocks.

5. Use Hay Nets or Feeders

Feeding from nets or elevated racks reduces waste and prevents horses from rooting through hay piles where foxtail seeds may accumulate.

6. Regular Dental and Mouth Checks

Routine dental care and regular mouth checks help detect early signs of irritation or injury from contaminated hay.

Additional Risks: Eyes and Skin

While mouth irritation is the most common issue, foxtail awns can also cause problems if they lodge in the eyes, nostrils, or skin. Horses may develop conjunctivitis, eye ulcers, or small abscesses if awns penetrate the soft tissue. Always check your horse’s eyes and face for signs of irritation, especially if foxtail hay has been fed.

Recognising Foxtail in Hay

Foxtail seed heads have a distinctive look once you know what to spot:

• Cylindrical, brush-like clusters (resembling a fox’s tail)
• Bristly and rough to the touch
• Often golden yellow or brown when dry
• Small, stiff awns that detach easily and stick to clothing or skin

Comparing foxtail to safe grasses such as timothy or orchard grass can help owners learn to identify it quickly.

Conclusion

Foxtail contamination in hay may seem like a minor issue, but it can cause major discomfort and health problems for horses. The sharp awns can injure delicate mouth tissues, leading to ulcers, infections, and feeding difficulties. Fortunately, with careful hay inspection, good pasture management, and prompt veterinary attention when problems arise, foxtail injuries are entirely preventable.

Always check your hay supply before feeding, stay alert to changes in your horse’s eating behaviour, and work with trusted suppliers to ensure your forage is clean and safe. A few minutes of vigilance can save your horse from weeks of painful irritation and help ensure a healthy, happy season of feeding.