Hoof conformation in Icelandic competition horses and its interrelationship with hoof pathologies and tölt performance. (May 2020) - Herbrecht, V.
Highlights: Many international Icelandic competition horses show hoof deformities or deviations from an ideal hoof balance. A broken hoof pastern axis and an imbalanced distal phalanx were most frequently observed. Some structural hoof deformities were associated with a longer dorsal hoof length. Longer dorsal hoof length and relatively larger hoof size were positively correlated with higher tölt marks incompetition. Abstract: In order to improve the four-beat-rhythm and forelimb action of the tölt in Icelandic horses (ICE), special shoeing techniques are applied particularly in the front hooves by increasing hoof length and height, or by adding weight to the distal limbs. Although regulations limit dorsal hoof wall length (LDHW ) in competition ICE, their shoeing often deviates from a biomechanically optimal distal limb conformation. This study aimed to qualitatively and quantitatively describe current shoeing practices of ICE in competition. Moreover, the influence of LDHW on the occurrence of deviations from a standard hoof conformation, as well as on tölt performance was investigated. At four European competition sites, hoof dimensions of 133 randomly selected ICE were measured manually, and limb conformation and hoof balance were described. Dorsopalmar/-plantar and lateromedial radiographs of the left front and hind hooves were taken of each horse. Various parameters related to hoof dimensions and balance were measured on radiographs using the Metron-Hoof-Pro software. Flares of the dorsal hoof wall had the highest prevalence of all investigated hoof deformities. Multiple logistic regression analysis revealed that longer LDHW was associated with the occurrence of toe flares ( P = 0.045), a broken hoof pastern axis ( P = 0.003), and asymmetry of the quarter wall heights ( P = 0.015). However, horses with a longer LDHW achieved higher scores in competition. In spite of its positive effect on tölt performance, a long LDHW is not recommendable as it may be associated with a higher prevalence of certain hoof deformities.