Effects of Horseshoe Characteristics and Surface Composition on Shear Loads on the Equine Digit

Introduction: Horseshoe characteristics and ground surface properties affect limb kinematics and incidence of injury. This project compared the effects of arena surface material and horseshoe traction features on shear forces on the equine digit.

Materials and Methods: Shear properties and vertical displacement were studied with eight paired equine cadaver hooves on dirt (sand) and synthetic (sand with fibre) surfaces at increasing normal loads (50, 100, 150, 200, and 225 lbs.). Hooves were shod with positive (toe grab), neutral (flat), and negative (sliding plate) traction features; and unshod hooves served as a control. Shear data were used to calculate angle of internal friction and cohesion. A repeated measures ANOVA assessed the effects of horseshoe feature, surface type, and their interaction on shear properties (p < 0.05).

Results: The dirt surface had greater cohesion (p = 0.031) and vertical displacement (p = 0.012). The synthetic surface had larger angle of internal friction (p = 0.022) and normalized maximum shear force (p = 0.026). Few, and only surface specific differences were observed among horseshoes.

Discussion/Conclusion: The dirt surface had lower normalized shear forces which resist horizontal movement, but greater cohesion and vertical displacement. Surface material had a greater effect than horseshoe characteristics on shear properties of the horseshoe-surface interface.

Acknowledgment: Financial support was provided by the Students Training in Advanced Research (STAR) Program through the University of California, Davis, School of Veterinary Medicine Endowment Funds. Farrier Products Distribution donated Kerckheart horseshoes.