"The incidence of problems related to the hoof wall has been estimated to be 30% or more," stated Robert M. Bowker, VMD, PhD, a professor of anatomy at Michigan State University, at the 2003 American Association of Equine Practitioners convention. "Resolution of hoof abnormalities by corrective trimming or shoeing depends on our understanding of the basic structure and function of the hoof wall as well as its short-term and long-term growth.

"Hoof wall growth has been studied by both light and electron microscopy; however, the process is still not completely understood," he added. The mechanisms of growth and adaptation of the hoof wall to various stresses have been a big focus in recent research. Bowker presented his observations and interpretations on these phenomena.

"The morphological features of the primary epidermal laminae (PEL) and the secondary epidermal laminae (SEL) around the perimeter of the hoof wall have formed much of our understanding of the inner hoof wall, its function, and its growth," he explained. "Many practices and treatments during trimming and shoeing by the farrier and veterinarian have been based on these hypotheses. The concepts of hoof wall growth and its origins from the coronet are well accepted, although they may not be fully understood. However, these current ideas of hoof wall and sole growth do not account for the possibility that the cellular constituents can change and adapt according to the environmental stresses imposed on the foot and, thus, alter their morphological features.

"Thus, although our treatments may be formulated according to our current understanding of the growth of the hoof, these latter ideas may be flawed," he continued