Horse Side Vet Guide ®

Equine Health Resource

White Line is Poor, Chalky or Black Material, Seedy Toe

Code Yellow - Contact Your Vet at Your Convenience for an Appointment

Code Yellow - Contact Your Vet at Your Convenience for an Appointment

    The white line is the laminar layer (the layer of interlocking “velcro”) that holds the outer hoof wall to the inner parts of the hoof. You can see a cross-section of the white line visible on the ground surface of the clean horse’s hoof, and located between the outside hoof wall and the sole. Genetics, nutrition, environment and management all play a role in the quality and health of the white line.

    In horses with normal, healthy hooves, the white line is narrow (about 3-5 mm thick) and does not trap debris. A poor quality white line is often wider, eroded away, or is soft and flakes or crumbles easily with a hoof knife.

    Poor white lines are a hallmark of horses with chronic founder (laminitis) and rotation of the coffin bone. It can be seen in horses suffering from chronic malnutrition. The condition of the white line is also related to genetics. White Line Disease is a breakdown of these attachments, a bacterial or fungal infection that is more easily managed if treated early.


    Assess your horse’s general health using the Whole Horse Exam (WHE), and assess the hoof. Consider whether the horse is showing any sign of lameness. Feel for digital pulse and heat in the feet. Compare one hoof to the other for reference. Share your findings and concerns with your vet.


    Your vet considers this finding with respect to whether or not the horse is lame. Diagnostics and treatment will be more aggressive if the horse is lame. In general, any poor quality “underrun” hoof should be removed.

    Author: Doug Thal DVM Dipl. ABVP


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