Can the hoof be shod without limiting the heel movement? A comparative study between barefoot, shoeing with conventional shoes and a split-toe shoe

Conventional shoeing restricts heel movement, which may have a negative effect on the orthopaedic health of the horse. A randomised crossover experimental study using noninvasive techniques was performed to compare the mediolateral heel movement in barefoot horses, horses shod with a conventional toe clipped shoe and with a new type of shoe with a split toe. In eight horses, 16 forelimbs were tested barefoot, shod with a conventional shoe and with the split-toe (ST) shoe, in random order. A displacement sensor was secured on the heels and measurements were collected continuously at a frequency of 679Hz while horses were exercised on a treadmill at the walk (1.8m/s), trot (3.5m/s) and canter (8m/s). Differences in heel movement between the conditions were analysed using a generalised estimating equations approach. The conventional shoe was associated with significantly less heel expansion compared with the ST shoe and barefoot situation in all gaits (P≤0.001). Heel expansion with the ST shoe was not significantly different from the barefoot condition. For all gaits, shoeing was associated with a significant reduction in heel contraction compared with the barefoot situation (P≤0.038), except for the heel contraction at the canter using a conventional shoe. In conclusion, the heel expansion with the ST shoe did not differ significantly from when the horse was barefoot, in contrast with the significant restriction of the heel movement when a conventional shoe was used.

The effect of hoof angle variations on dorsal lamellar load in the equine hoof

REASONS FOR PERFORMING STUDY

In the treatment of laminitis it is believed that reducing tension in the deep digital flexor tendon by raising the palmar angle of the hoof can reduce the load on the dorsal lamellae, allowing them to heal or prevent further damage.

OBJECTIVE

To determine the effect of alterations in hoof angle on the load in the dorsal laminar junction.

METHODS

Biomechanical finite element models of equine hooves were created with palmar angles of the distal phalanx varying from 0-15°. Tissue material relations accounting for anisotropy and the effect of moisture were used. Loading conditions simulating the stages in the stance where the vertical ground reaction force, midstance joint moment and breakover joint moment were maximal, were applied to the models. The loads were adjusted to account for the reduction in joint moment caused by increasing the palmar angle. Models were compared using the stored elastic energy, an indication of load, which was sampled in the dorsal laminar junction.

RESULTS

For all loading cases, increasing the palmar angle increased the stored elastic energy in the dorsal laminar junction. The stored elastic energy near the proximal laminar junction border for a palmar angle of 15° was between 1.3 and 3.8 times that for a palmar angle of 0°. Stored elastic energy at the distal laminar junction border was small in all cases. For the breakover case, stored elastic energy at the proximal border also increased with increasing palmar angle.

CONCLUSIONS AND POTENTIAL RELEVANCE

The models in this study predict that raising the palmar angle increases the load on the dorsal laminar junction. Therefore, hoof care interventions that raise the palmar angle in order to reduce the dorsal lamellae load may not achieve this outcome.