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Observation
What you see. The starting point for addressing any equine health related issue is your observation.

YOU ARE OBSERVING

Widened White Line of the Hoof

Summary

The white line of the sole of the foot represents the visible portion of the laminar layers, the junction of the hoof wall and the underlying tissues bonded to the coffin bone.

In normal healthy horses, the white line should be just a few millimeters wide. When the laminae are damaged (most commonly by laminitis), there is stretching of these tissues, resulting in a widened white line. This will only be visible on a barefoot horse, and may require cleaning and light trimming of the dried sole in order to see it.

A widened white line indicates some rotation or movement of the coffin bone within the hoof, and is commonly associated with chronic laminitis. It can also be seen in horses with club foot. In many cases, the white line becomes pitted and porous, allowing thrush to thrive, and predisposing to abscess formation.

  • Code Orange

    Call Your Vet at Their First Available Office Hours
    • If you notice lameness in addition to this sign.

  • Code Yellow

    Contact Your Vet at Your Convenience for an Appointment
    • If you do not notice any lameness or stiffness.
You also might be observing
Very Common
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Rare
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your role

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What To Do

Study the white line when you examine your horse's feet and know what it looks like in health. If you notice what you think is a widened white line, in the absence of other signs, take a photo of it and send it to your vet or farrier for discussion. To the extent possible, always pick out any loose material and especially black thrush material from the white line.

your vet's role

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A primary goal for your vet is to determine whether laminitis is the cause of this sign. They look for other signs of chronic laminitis (founder), including dropped sole, collapsed front of hoof wall, and unevenly spaced growth rings on the hoof wall.

They carefully consider the horse's history and examination findings. Radiographs are the best method for visualizing the position of the coffin bone within the foot and are usually needed. Radiographs are also helpful to farriers in determining ideal shoeing technique and shoe placement.
Questions Your Vet Might Ask:
  • To your knowledge, has the horse ever had laminitis?
  • How long have you owned or leased the horse?
  • Does your horse have a history of lameness?
  • Is the horse limping or lame?
  • If the horse is lame, how lame?
  • What is the horse's Body Condition Score (BCS)?
  • Does the sole seem dropped, flat or convex?
  • Does the front (dorsal) hoof wall appear dished or concave?
  • Does the horse have what you think is "club footed" conformation?
  • Describe the current shoeing.

further reading & resources

Author: Doug Thal DVM Dipl. ABVP