Hooves that evolved for wear now break down from underuse.

Evidence

Shoeing itself is still typically functional, even if the long toe is not. Once, shoes were needed to protect the hoof from overuse and wear. Today, the hoof needs protection from underuse. The rub here is that the new owners, while looking to connect to nature or tradition through their horses, find their horses in unnatural conditions and nontraditional uses (McBane, 1992). Given domestic conditions and light duty, the hoof becomes soft and the coffin bone sinks, leading to lameness. The old design, in promoting a long toe, does not allow the toe to break-over nor does it allow for sole pressure. In cases where the horse gets a lot of work in frequent training and competition, the round-toed shoe may be of some utility. More often, the long toe and lack of sole callous are a leading cause of navicular syndrome, and providing toe break-over and pressure to the digital cushion are important in the treatment of laminitis (Bowker et al., 1993; 1998). — Georg Schreyögg and Jörg Sydow, The Hidden Dynamics of Path Dependence, 631

Categorization

• SEED: Angle: the domestication inversion — body parts evolved for harsh use become diseased when the use disappears, like the horse hoof turned soft by idleness.
• QUESTION: How many modern equine lameness diagnoses trace to the mismatch between the hoof’s evolutionary design and stall life?