Immediate effect of a halfmesh pad and packer combination on movement symmetry of vertical head and pelvic displacement

Pads and packers added between hoof and horseshoe are designed to damp impact vibrations and support the palmar aspect of the sole. This may help with force distribution and during rehabilitation from foot-related impairments. Study objective was to quantify gait changes related to contralateral weight support and vertical pushoff differences, after forelimb shoeing with a specific pad/packer combination. In an experimental study with convenience sampling, ten Thoroughbred racehorses (2–8 years,1.54 m to 1.66 m) in competitive race training were shod all round by a professional farrier with steel training plates (Royal Kerckhaert horseshoes). Gait analysis was conducted before and after addition of a halfmesh pad (3D Hoofcare) and packer (Glue-U Shudim Putty) to both forelimbs. Absolute values of normalized vertical head and pelvic movement symmetry, provided by an equine video gait analysis app (Sleip) were compared with a Wilcoxon sign rank test (P < 0.05) before and after adding a pad/packer combination. Baseline movement symmetry varied between 0.1 (head minimum difference) and 0.55 (head maximum difference). Head movement asymmetry showed small increases after pad/packer fitting (all P ≤ 0.046) by 4–10 % of the range of motion. Nine of ten horses showed increased head movement asymmetry. Pelvic movement was unaffected (all P ≥ 0.484). The change in vertical head movement asymmetry after fitting a pad/packer combination indicates small immediate changes in vertical force distribution between contra-lateral forelimbs based on previously documented force associations. Further studies at varying time points after pad/packer fitting might help with establishing the biological relevance of the small changes found here.