Farriers Laura Florence and Bryan Farcus answer questions on treating your horse’s hoof thrush
Thrush invades the frog of the hoof and thrives on necrotic tissue. It is identified by a particularly unpleasant smell and an oily, black discharge. Usually found in the grooves on either side of the frog, thrush spreads by going deeper, rather than superficially across a tissue’s surface. Conditions conducive to the development of thrush include:
- anaerobic (no oxygen) conditions like a dirty stall or persistently muddy paddock
- extremely wet weather
- absence of or infrequent hoof cleaning
- abnormal hoof conformation of a deep central sulcus in the frog
Q: Is thrush a synonym for hoof infection? If no, how does it differ from an infection?
Bryan: There seems to be some debate whether thrush in horses is more of a fungus or bacteria. Most equine science texts list an anaerobic bacterium called Sphaerophorus necrophorus as the main culprit. However, since thrush can also occur in the mucous membranes of humans, as a yeast-like microscopic fungal form, some argue that a fungal organism call Candida albicans can play a much greater role. Regardless of its origin, one constant remains — prevention.
Laura: Horses can be plagued by chronic and debilitating hoof infections. Other bacterial and fungal agents are at play in horses’ feet, causing infection and damage. Some attack the white line and hoof wall, others cause lesions on the coronary band and pastern. Thrush is distinct from other infections in that it localizes in the frog.
Q: What is the worst case scenario for chronic/untreated thrush?
Bryan: Permanent damage to the frog corium (sensitive underlying tissues), Deep Digital Cushion infection, and in the most severe cases an invasion of the attachment of the Deep Flexor Tendon to the bottom of the coffin bone, resulting in permanent lameness.
Laura: It is possible for thrush to become so entrenched that it can reach sensitive tissue deep in the foot and cause serious lameness and health risk. Severe infection can be identified by compressing the frog with strong thumb pressure and/or hoof testers. Reaction will indicate a deep invasion of thrush.
Q: What are your favorite treatments for thrush?
Bryan: One of my most effective treatments for potential or minor cases is a thorough hoof picking and a hoof wash/spray of a 50:50 mixture of water and either hydrogen peroxide or white vinegar. Caution: do not use this on any cases that have advanced into the bleeding state; instead refer to your veterinarian for advice.
Laura: Treatments vary widely and many are effective, with consistent, thorough attention. Clean the frog daily using a diluted agent of a substance such as apple cider vinegar, Borax powder, or Lysol. Gently but thoroughly clean all of the deep crevices. Have your farrier trim away any loose flaps of dead frog. This will allow more air contact and easier cleaning. Take care not to poke and scrub too vigorously – infected frog tissue can be painful and can easily bleed. Use a squirt bottle of whatever solution you have chosen to irrigate the area and loosen debris (I re-purpose dish liquid bottles for this). An old cotton t-shirt cut into 4 or 5 inch squares is great for gently wiping through the sulci of the frog. The clean soft squares can “floss” the deep central crevice. Remember - gently! Follow this cleaning treatment with an application of healing salve or ointment to nourish damaged tissue. If the infection is deep and the frog soft and painful, apply raw honey by saturating cotton balls and carefully place into the frog. Just leave the cotton balls there until the next treatment! After a few weeks of the raw honey, switch to any of the following: over-the-counter fungal creams, cow mastitis creams from your veterinarian, or calendula salves. If deep areas in the frog stay moist, try applying a paste made up of SORE NO-MORE® The Sauce and sugar to help with drying. The key is to focus on healing the frog from deep to shallow, inside out. It is important to balance killing the bad stuff while supporting the good.
Once thrush rears its smelly head, expect treatment to be long term. Attention to diet, exercise, environment and regular hoof trimming are critical, in addition to topical application of cleaning and healing agents.
Resources: The Principles of Horseshoeing (P3), D. Butler and J. Butler; Mosby’s Medical, Nursing, & Allied Health Dictionary, 6th Ed., D. Anderson, J. Keith, P. Novak
Laura Florence is an American Farrier’s Association Certified Farrier serving clients in southeastern Pennsylvania. A former Resident Farrier with the University of Pennsylvania, New Bolton Center Farrier Service, Laura began private practice in 2007, rehabilitating and maintaining horses’ hooves through a holistic approach. www.holistichoofcare.com , 484-868-3715.
Bryan S. Farcus MA, CJF, is the creator of a select line of “Farrier-Friendly™” products and author of the “Farrier-Friendly™” series of articles that appear in horse magazines throughout the US. Bryan currently works with horses and their owners in Ohio and West Virginia. www.farrierfriendly.com
Common symptoms of thrush
- Resistance to having feet picked up and cleaned/inspected
- Sensitive, painful frog, usually with a deep central cleft
- Toe first landing, even when the foot looks healthy
- Hoof wall separation, flat soles, high bars and sunken frogs
- Irregular hoof wear patterns due to a compromised gait
- “Wry” or twisted hooves
- Thin, distorted or displaced frogs
- Contracted heels that won’t relax and spread
- Club feet that began in mid-life or after an injury or laminitic episode
- Seasonal soundness issues
Source: No Horsing Around, LLC, www.NoHorsingAroundLLC.com