Veterinary advice should be sought before applying any treatment or vaccine.


Thrush is a very common bacterial infection of hoof, specifically the frog area. It is caused by Fusobacterium necrophorum, a gram-negative obligate anaerobic bacillus. Thrush is characterized by the presence of foul smelling black material within the sulci of the frog. Thrush is often over diagnosed in horses, especially by horse owners, as the early stages of canker often greatly resemble clinical signs seen in horses with thrush. If any bleeding is observed with manipulation of any of the tissues, lesions extend outside of the frog area, or the horse is not responding to thrush treatment, it is usually indicative of canker.

F. necrophorum thrives in excessively wet, or muddy soil conditions and dark, poorly ventilated, or unsanitary environments.


Foul-smelling black or gray hoof material
Area will easily break and crumble when scraped with hoof pick
Pain if underlying structure damage


  • History
  • Clinical signs
  • Physical exam
  • Culture


Environmental modificationsHorses should be moved to a dry, clean environment and housed in stalls with at least 3 inches of fresh, quality bedding that is cleaned daily.
Balanced trimconducted by a certified farrier in order to remove the necrotic tissue
CleansingHorse's feet should be picked out daily, and scrubbed with dilute iodine solution or commercial thrush-treatment product
Hoof packingUsing a mixture of sugar and betadine
Surgical debridementMay be necessary in severe cases, alongside aggressive therapy.


  • Regular hoof trimming by a certified farrier every 4 to 6 weeks.
  • Picking out the horses feet on a daily basis, especially after being turned out in mud conditions.
  • Providing horses with at least 3 inches of clean, quality bedding while in stalls, which is picked out daily.
  • Minimizing mud and water accumulation in pastures, by improving footing and drainage.


Usually good once treatment begins

Scientific Research References

Good Overviews

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Risk Factors

  • Horses with contracted heels or deep clefts
  • Insufficient exercise
  • Not providing enough bedding for horses to stand on in stalls and/or not regularly picking out soiled stalls.
  • Excessive muddy conditions such as pastures with poor drainage or excessive rainfall or flooding.
  • Horses with hoof abnormalities, such as excessive toe length or contracted heels
  • Horses that are shod with full pads or snow pads