Theoretically, treatment for white line disease should be simple — kill infection-causing bacteria and fungi. In reality, treating white line disease can be far more complicated.

Bacteria and fungi naturally exist inside the hoof wall in a mutually beneficial relationship. In “Taking the Mystery Out of White Line Disease,” SBS Equine researchers Dr. M. John Partens and Dr. Richard Shakalis explained that each organism breaks down in the hoof in a different manner.

In a healthy hoof, these organisms keep each other in a regulated balance. In an unhealthy foot, they take advantage of access to a rich blood supply and create an infection, most often in the stratum medium. Because these organisms counteract each other and prevent one another from over-generating, one can’t be corrected without correcting the other.

Although bacteria and fungi cause white line disease, there are several misconceptions about why some horses are more prone to the disease than others.

“The most important thing to remember is that white line disease is a secondary issue,” says Dr. Raul Bras, a farrier and veterinarian at Rood & Riddle Equine Hospital in Lexington, Ky. “It is secondary to separation of the hoof wall caused by hoof capsule distortion or another pathology.”

Distortions and hoof wall…