White Line Disease

With the unusually wet conditions we have experienced this year we have been
seeing multiple foot related concerns. One of the more common findings has
been separation of the hoof wall due to the white line being compromised.
Common factors that lead to this is environmental factors (excessive dry or wet
conditions), nutritional deficiencies, mechanical factors such as neglected feet,
long toes, imbalanced feet, or chronic laminitis. This allows bacteria and fungus
that is normally present within the environment to colonize and facilitate the
progression of the disease by breaking down the internal layers of the hoof wall
perpetuating the separation. The most commonly areas affected is the toe and
quarter regions of the foot as they receive the most stress and pulling forces
during breakover.

Typically this is an incidental finding at the time of routine trimming and usually
of minor concern if superficial. From the solar surface the white line will have
separated from the hoof wall and sole thus weakening the junction between these
two structures. The white line at times be wider than normal and instead of a
solid structure will chalky consistency and gray to black in appearance. This area
should be monitored and if probed to be sure there is no undermining of the hoof
wall. In minor cases it rarely causes lameness and is more of a nuisance but the
concern is that is there is enough separation present instability develops between
the coffin bone and hoof wall. When this occurs we see varying degrees of
lameness and radiographs can be of value to determine amount of separation and
if rotation of the coffin bone has occurred due to the instability.

Treatment involves removal of all detached hoof wall back to normal healthy
attached hoof wall. The purpose of this is to expose this area to remove any
pockets and rid the foot of compromised hoof tissue. Diligent after care is
essential and keeping the area clean, a good hoof pick or stout brush is helpful,
dry, and treated with a topical application (we use a combination of diluted
copper sulfate and vinegar). A shoe is usually beneficial to protect the sole and
junction of normal and resected hoof wall. Considering most of these affect the
toe region placing a shoe pulling the breakover back as much as possible will aid
in decreasing the pulling stresses placed on the foot at the time of breakover. With
that being said some farriers have had success with not being as aggressive with
resecting the hoof wall in minor cases. The pocket will be dug out to remove the
necrotic underlying hoof wall, packed with copper sulfate and then Keratex wax
or puddy will be melted into the defect to hopefully prevent further
contamination.

Prognosis for most cases is good pending proper management and lack of
complicating factors. Providing a suitable environment with a clean dry area and
avoiding moisture extremes (this includes night turnout to avoid heavy dew) will
typically aid in a quicker recovery.

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