Therapeutic farriery of the hind feet for horses with hindlimb orthopaedic injuries

The role of hoof mechanics in delivering maximal performance in horses has been studied in detail and its importance in the front feet has been defined (Davies, 2002). To maximise mechanical efficiency, the hoof should be balanced in both the dorsopalmar/plantar (DP) and mediolateral (ML) planes (Davies, 2002). The definition of the ideal hoof balance is still debated among veterinarians and farriers, but it is accepted that the conformation and balance of both the hoof and distal limb, and their interaction with movement and ground surfaces, are key factors in equine hoof and distal limb health and performance (Johnston and Back, 2006). It has been shown that forces at the toe, and the medial and lateral heels together, are optimally distributed when the hoof and pastern angles are aligned (Balch et al, 1997; Davies, 2002), such as with a straight hoof-pastern axis. Under these circumstances, the angle between the solar surface of the pedal bone and the ground contact surface should be approximately 5° (Back and Pille, 2013). For optimal foot conformation, it is generally acknowledged that this angle should be 2–10° (Parks, 2003). When this angle is negative, it is widely known as a negative palmar/plantar angle (Redden, 2003). Floyd (2010) used a I–IV grading system for treatment and prognosis in horses with negative palmar angles. A grade I is mild, meaning there is sufficient depth under the dorsal margin of the pedal bone and trimming alone will restore a positive pedal bone angle and straight hoof-pastern axis (Table 1).