Keratinolytic disease of the zona alba (KDZA), commonly known as white line disease, is a hoof pathology present across a wide range of breeds and disciplines. Referred to previously as hollow wall or seedy toe — as well as by various other descriptors — KDZA emerged as the most clinically correct term for the pathology when it was introduced in 2018 by fourth-generation farrier and author Simon Curtis, PhD, FWCF (Hons), HonAssocRVCS, of Newmarket, England.

White line disease has been the widely accepted term to describe a recognizable separation in the hoof wall in which keratinolytic pathogens have invaded since the 1990s, says Sarah Logie, FWCF. However, the Inverness, Scotland-based farrier cautions that terms like seedy toe and white line disease are often misleading.

“Both descriptions involve the growth of the same anaerobic bacteria and subsequent…