Equine hoof wall: structure, properties, and bioinspired designs.
Authors: Benjamin S. Lazarus, Rachel K. Luu, Samuel Ruiz-Pérez, W. B. A. Bezerra, Kevin Becerra-Santamaria, V. Leung, Victor Hugo Lopez Durazo, I. Jasiuk, J. Barbosa, M. Meyers
Journal: Acta biomaterialia
Summary
# Editorial Summary Lazarus et al. (2022) undertook a comprehensive structural and mechanical analysis of equine hoof wall tissue to explain how it achieves exceptional impact resistance despite repeated loading. Using advanced imaging alongside mechanical testing—including creep, relaxation, and drop tower impact studies—the researchers identified previously undocumented features such as tubule bridges and characterised the tissue's hydration-dependent viscoelasticity through a simplified Maxwell-Weichert model. The hoof wall's hierarchical structure operates through distinct failure mechanisms depending on impact energy: at lower energies, the reinforced tubular architecture dominates energy dissipation, whilst higher-impact events engage the intertubular lamellae, with the intertwined nature of these components working together to enhance overall toughness through fibre bridging effects. The specific hydration gradient within the keratin matrix appears critical for distributing stresses evenly, reducing internal stress concentrations that would otherwise arise from the stiffness variations inherent to the composite structure. For practitioners managing hoof health, these findings underscore the importance of maintaining optimal hydration status in hoof tissue—through appropriate environmental moisture exposure, dietary factors, and farriery practices—to preserve the tissue's capacity to manage both routine and exceptional loading demands; the research also validates the biomechanical rationale behind certain farriery design principles that incorporate graduated material properties and load distribution strategies.
Read the full abstract on PubMed
Practical Takeaways
- •Understanding the hoof wall's hierarchical structure and hydration gradient may inform farriery approaches to hoof care, particularly regarding moisture management and its role in maintaining impact resilience
- •The dominance of different structural features at different impact energies suggests that hoof conditioning and shoeing strategies should account for varying work intensities and loading rates
- •Findings on the intertwined nature of tubule and matrix reinforcement highlight the importance of preserving natural hoof wall integrity rather than removing or severely modifying wall structure
Key Findings
- •Horse hoof wall contains previously uncharacterized tubule bridges that contribute to its hierarchical fracture control mechanism
- •Hydration gradient in hoof keratin reduces internal stresses from stiffness variations, described by Maxwell-Weichert viscoelastic model
- •Tubular structure dominates fracture behavior at lower impact energies while intertubular lamellae control failure at higher energies
- •Bioinspired additively manufactured structures incorporating gradient and lamellar designs significantly reduced damage in dynamic impact testing