So many factors affect the way the hoof grows that it can be difficult to unravel the mystery.
A recent study into hoof growth has approached the subject from several directions: equine medicine, maths, physics and stem cell biology have all played a part.
The findings have revealed a clearer understanding of how equine hooves grow and how abnormal hoof shapes may develop.
The study entitled ‘Physics of animal health: On the mechanobiology of hoof growth and form’ was conducted by the School of Veterinary Medicine and Science at the University of Nottingham in collaboration with the WALTHAM Centre for Pet Nutrition and the Royal Veterinary College. A full report is published in the Royal Society Interface Journal.
Lead author Dr Cyril Rauch, of the School of Veterinary Medicine and Science, University of Nottingham, 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, of the Royal Veterinary College, said: “We believe that this novel approach has the potential to provide alternative directions to follow with respect to understanding chronic hoof pathologies.”
Laboratory -based studies looked at how the synthesis of the hoof capsule starts from the coronet with the soft papillae undergoing gradual transition through three interpapillary regions into hard keratinised tissue.
Mathematics, physics and cell biology were then used 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.
A field study looked at one hundred and twenty-nine horses. All were at least 5 years old and under 144 cm (less than 14.2hh) high with shoes. They were healthy at the time of evaluation and none had a history of laminitis/hoof conditions, or pre-existing health conditions; neither had they been treated for pituitary pars intermedia dysfunction (PPID - Equine Cushing’s disease).
The research team recorded horse weight and Body Condition Score, hoof width and they measured the curvature of the dorsal wall from standardised photographs. This 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 cells responsible for producing the hoof wall) to grow in culture. The researchers suggest that if this happens over time in 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 Dr Menzies-Gow. “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.”
For more details, see:
R Al-Agele; E Paul; S Taylor; C Watson; C Sturrock; M Drakopoulos; R C Atwood; C S Rutland; NJ Menzies-Gow; E Knowles; J Elliott; P Harris; C Rauch. (2019) Physics of animal health: On the mechanobiology of hoof growth and form.
Journal of the Royal Society Interface, (2019) Vol 16 Issue 155