Heel Expansion and Deformation vary with Horseshoe Nail Positions

Introduction: Long toe/low heel (underrun heel) hoof conformation has been associated with increased risk for fetlock injuries. Our objective was to determine if nails used to secure a horseshoe to the hoof have an impact on hoof deformability which could lead to an underrun heel.

Materials and Methods: Nine cadaveric normal forelimbs were studied. Hooves were instrumented for measurements of heel expansion and hoof wall distortion using rosette strain gauges and kinematic markers. Hoof motions were measured during axial limb compression to canter midstance load (6700 N). Treatments consisted of no shoe (noshoe), toe nails (2nail), toe plus quarter nails (6nail), and toe plus quarter plus heel nails (10nail) and were compared using a repeated measures analysis of variance (p < 0.05).

Results: Heel expansion was greater for the noshoe compared with all nail treatments. Nail treatments resulted in hoof wall principal strain directions moving dorsally and the heels moving proximodorsally.

Discussion/Conclusion: Application of shoes retards hoof expansion, and thus could adversely affect load attenuation. The pattern of hoof wall distortion was consistent with development of the underrun heel hoof conformation.

Acknowledgement: Supported in part by the Center for Equine Health with funds provided by the State of California satellite wagering fund and contributions by private donors. The authors thank Tanya Garcia-Nolen, Kirk Adkins, Dr Ellen Singer, Shane Westman, and Dr Neil Willits for technical and statistical assistance.

No conflict of interest has been declared by the author(s).