New collaborative work between researchers in equine medicine, maths, physics and stem cell biology has resulted in a clearer understanding of how equine hooves grow and how abnormal hoof shapes may develop.
The lead author Dr Cyril Rauch said: “With new scientific inputs from physics, mathematics and biology, this study provides an entirely new paradigm regarding hard growing tissues such as the horse hoof, which can be applied across cattle, sheep and other species, to unify a set of apparently disparate conditions and clarify the roles of physics and/or biology.”
Nicola Menzies-Gow added: “We believe that this novel approach has the potential to provide alternative directions to follow with respect to understanding chronic hoof pathologies.”
The study published in the prestigious Royal Society Interface Journal and entitled Physics of animal health: On the mechanobiology of hoof growth and form was conducted by the School of Veterinary Medicine and Science at University of Nottingham in collaboration with the WALTHAM Centre for Pet Nutrition and the Royal Veterinary College.
Combining mathematics, physics and biology using hooves from horses euthanased for non-research purposes, the study revealed how it is possible for the hoof growth rate to be greater than the potential proliferation rate of epithelial cells. It also explained how the synthesis of the hoof capsule starts from the coronet and that the soft papillae undergo gradual transition through three interpapillary regions into hard keratinised tissue. Mathematics, physics and cell biology were then utilised in the study to explain and describe how the dorsal hoof wall can grow in a curved manner rather than the usual straight manner as a result of faster growth from the coronary band at the quarters compared to the toe region.
Evaluation of the feet from live underweight and obese subjects (assessed using Body Condition Scoring) allowed the influence of body weight on the balances of the stresses affecting hoof growth to be evaluated. The results suggest that being proportionally heavier may promote straighter hoof growth and that being too lean may precipitate poor hoof growth and the development of a hoof with a dorsal curved shape.
The study also showed that a high concentration of insulin stimulated equine progenitor keratinocytes (the outermost layer of cells on the hoof wall) to grow in culture. If this also happens chronically within the live animal, it is possible that it could affect the growth stresses within the hoof and so promote a dorsal curved hoof shape.
“These results taken together can explain how the hoof grows and how it is possible for it to develop a dorsal curvature,” said Nicola. “However, it should be acknowledged that this does not take into account the genetic or metabolic influences on hoof growth nor the role of hoof trimming and shoeing in maintaining a mechanically healthy hoof. It is appreciated that the underlying biology of hoof growth remains an essential factor for hoof pathologies.”
Dr Cyril Rauch continued: “Given that the hoof is a weight bearing element it is essential to untangle the biology from the physics in this system; only then can meaningful biological and/or physical causes be prescribed for particular hoof shape. Removing the cause(s) when physically or biologically possible is essential to resolve hoof conditions.”
1 Al-Agele, R; Paul, E; Taylor, S; Watson, C; Sturrock, C; Drakopoulos, M; Atwood, R C; Rutland, C S; Menzies-Gow, N J; Knowles, E; Elliott, J; Harris, P; Rauch, C. (2019) Physics of animal health: On the mechanobiology of hoof growth and form. Journal of the Royal Society Interface, http://doi.org/10.1098/rsif.2019.0214