>From Hoof Rehab, which has to do with the previous post titled: Newly Discovered Shock Absorber in the Equine Foot, located here:
http://pets.groups.yahoo.com/group/IceHorses/message/112548 The most common cause of hoof sensitivity and the biggest crux we face, actually lies in the back of the foot. The wild horses show us that the hoof should have an arch from front to back, like the arch of your foot and that the heel bulbs/frogs and heels should bear the initial impact force together, with a low heel that doesn't lift the frog off the ground. The coffin bone should shape the front half of the foot, thus the front half of that natural arch so the healthy hoof at rest should have a palmar angle of 3-5 degrees relative to the ground, with the back of P3 being slightly elevated. (Or it should be parallel to whatever the angle the solar surface of the front half of the foot may naturally be.) On hard impact, this arch compresses flat and the back of the foot should be loaded first, giving us a ground parallel impact force to P3. The "soundness problems" some barefoot trimmers face lie in the placing of more emphasis to the hoof mechanics of the horse standing on concrete, than to the mechanics of the hoof in motion.... The mechanics of impact are by far the most significant. Dr. Robert Bowker's (Michigan State University) research reveals that traditionally managed domestic horses consistently fail to fully develop the back of the foot. The digital cushion is a very important nerve center hidden beneath the frog. When a foal is born, the digital cushion is comprised of fatty tissues, offering the right amount of protection to the nerves, for the impact force generated by the weight of a foal. The nerves are "exposed" enough to provide "feel", yet protected enough not to register pain on rocky terrain. Every step the wild foal makes causes a bit of growth of dense fibrocartilage to spread through the digital cushion. It starts its journey at the front, just beneath the apex of the frog and gradually spreads towards the heel bulbs. By the time a wild horse reaches adult weight, the digital cushion has been transformed into a tough, dense mass of fibrocartilage. (The same process can happen for domestic horses under natural hoof care, with freedom to move.) At the same time, this movement, hoof expansion and flexion has been at work stimulating and completing the development of the lateral cartilages. The lateral cartilages have grown from 1/8 inch thick to a full inch thick (in the lower part where you cannot see them above the hairline.), and a "floor" of cartilage has also developed between the frog's corium and the digital cushion. This completed development of strong but flexible cartilage provides a very solid foundation for the back half of the foot. The end result is a very stable but yielding, shock absorbing "back half" of the foot. The "nerve center" in the digital cushion is well protected; nestled within the denser digital cushion and encased within the mass of thick lateral cartilage. This healthy arrangement protects the nerves from "overstimulation" and sensitivity, under the impact force of an adult horse. A lack of frog stimulation and hoof distortion from birth throughout our domestic horses' lives cause this process to be much slower or nonexistent. Often a 1200 pound adult domestic foot has inner structures of digital cushion and cartilage that are suitable to offer the protection to the nerves that are normal for a 200 pound foal. Many of our horses' hooves have grown to adult size, but still have the 1/8 inch thick immature lateral cartilages, little or no "floor" of cartilage, and a digital cushion comprised of weakly constructed fatty tissue. What does this mean? Most of our frogs are incapable of being the "landing zone" nature intended. (Many horses' heels remain high heeled and contracted as a pure defense mechanism to limit the pressure on the underdeveloped structures.) How do we fix this? Miles and miles of stimulation to the rear half of the foot. According to Dr. Bowker, this process can begin at any age, but must be done while the horse is barefoot. Frog pressure alone doesn't cut it. It is pressure and release. A fixed shoeing method that provides constant frog pressure counts as only one impact out of thousands the horse needs to complete this development. (The same goes with sole pressure and development as well, by the way). The other important factor to this development of proper structure (specifically the lateral cartilages) is the flexion of the hoof capsule; not just expansion, but distortion front to back and the "twisting" of the hoof capsule on firm, varied terrain. When a foal is born, all four feet are the EXACT same (even microscopically according to Dr. Bowker). The dramatically greater work load of the foal's hind feet allow for much more natural development in the back of the hoof. By the time most domestic horses reach adult weight, they have all the right stuff in the hinds, and incomplete development of the fronts. This, of course, leads to sensitive front feet and is also the ONLY reason the fronts are more susceptible to founder and navicular disease than the hinds. (Aside from improper trimming/shoeing.) So in other words, without changing anything in an individual horse's lifestyle, diet or terrain, the fronts could be just as healthy as the hinds if only there was more frog pressure every day; more work; more stimulation and more hoof flexion. [Foals raised under routine, competent natural hoof care do consistently develop proper structure of their front feet, though, so a large part of this is simply the tradition of allowing foal hooves to overgrow, lifting the living foot out of function, and to then shoe them before the development of the foot is complete. I should point out here that when the foot is allowed to develop properly and the foals weight hasn't fallen behind its inner structure development, the result will be frogs that actually protrude longer than the heels; yearning to absorb more energy. Don't fight this; it's a good thing! ] _________________________ Judy http://icehorses.net http://clickryder.com
