The influence of different horseshoes and ground substrates on mid-stance hoof orientation at the walk.

Abstract

BACKGROUND: Horseshoes with modified contact surfaces combined with deformable ground substrates are used to change hoof orientation during mid-stance, for example, for therapeutic reasons. OBJECTIVES: To measure the effect of horseshoes and ground substrates on sagittal and transverse plane hoof orientation at mid-stance using a dorsal hoof wall mounted triaxial accelerometer. STUDY DESIGN: In vivo experiment, randomised crossover design. METHODS: Differences in sagittal and transverse plane angles between standing and mid-stance of the left front hoof of six horses walking with regular horseshoes, egg bar, toe-wide, medial-wide, lateral-wide and three-degree egg bar shoes on turf, sand and hard ground substrates were assessed with linear mixed models with horseshoe and substrate type as fixed factors (p&#x2009;<&#x2009;0.05) for each animal. RESULTS: Hoof angles were significantly affected by horseshoe (p&#x2009;<&#x2009;0.001), surface (p&#x2009;<&#x2009;0.001) and the combination (p&#x2009;<&#x2009;0.001). The sagittal plane angle increased in deformable ground substrates at walk-in mid-stance on turf [mean (&#xb1;standard deviation): 2.6&#xb0; (&#xb1;3.8&#xb0;)] and on sand [2.6&#xb0; (&#xb1;4.1&#xb0;)] across all shoes. The greatest increase was observed with egg bar shoes [turf: 4.37&#xb0; (&#xb1;3.82&#xb0;); sand 4.69&#xb0; (&#xb1;3.83&#xb0;)]. There was a tendency for the hoof to sink laterally into deformable ground substrates among all shoes [turf: 1.11&#xb0; (&#xb1;1.49&#xb0;); sand: 0.93&#xb0; (&#xb1;1.93&#xb0;)]. Medial-wide shoes increased the lateral sinking [turf: 2.00&#xb0; (&#xb1;1.63&#xb0;); sand: 1.79&#xb0; (&#xb1;1.58&#xb0;)]. Lateral-wide shoes reduced the lateral sinking on turf [0.62&#xb0; (&#xb1;1.26&#xb0;)] and induced a marginal medial sinking on sand [-0.007&#xb0; (&#xb1;2.03&#xb0;)]. MAIN LIMITATIONS: The substrate properties were not quantitatively assessed, and observations were limited to front hooves at the walk. A larger sample size would be preferable. CONCLUSIONS: Mid-stance hoof orientation changes with specific combinations of shoes and ground substrates in the walking horse.