At the end of the horse's leg is not something dead and hard but an encapsulated vital organ known as the hoof. It is an almost sole means of survival and has many vital functions. These functions are supported by and are dependent upon hoof mechanism, the pumping action of the hooves. Full hoof mechanism is only possible with proper barefoot hoof form on appropriate, firm terrain. Primarily there are 6 categories of hoof function: Protection/Traction, Metabolic, Circulatory Pump, Shock Absorption, Heat Production, and Meridian Stimulation.
Correct hoof shape is critical for proper function and good traction. Apart from being a regenerating "boot", protecting and insulating the inner structure, the hoof capsule is responsible for suspending the skeleton and therefore the weight and impact of the horse. The presence of a pumping action in the hooves and proper metabolic temperature means tissues are developed properly to best support the horse. Hoof mechanism also provides a suction cup effect on slicker surfaces. Without hoof mechanism, and therefore proper circulation, neural response is reduced. In a similar way to your hands losing sensitivity when they are cold, a horse does not "feel" as well with decreased circulation.
The metabolism of horn production is the organism's natural means of ridding the body of waste, comparable to urine and bile production. Since the organism can make no further use of them, the body must eliminate these wastes. This metabolism is of utmost importance for the horse, since the four hooves produce a large amount of protein waste. If too little horn production takes place, too much waste stays in the blood stream, and the body becomes slowly poisoned. This often shows up through skin problems (eczema, improper shedding) and disruptions in function of the liver, heart and muscle activities.
For healthy metabolism to exist in the horse, the hooves must be thoroughly nourished with blood. Circulation supplies fresh material enabling metabolic processes in the hoof to properly take place. A continual fresh supply of nutrients and oxygen not only ensures that waste is excreted but that proper horn structure is produced to optimally support the horse.
When not bearing weight, the hoof capsule sits snugly around the coffin bone and lateral cartilages. While the horse bears weight, the hoof capsule widens and the sole draws flat, leaving more room between the hoof capsule and coffin bone. Even when bearing normal standing weight the hoof capsule is already expanded and the sole less concave, which allows the corium to engorge with blood. Since in a natural state the horse does not pause for any long periods of time, the hoof capsule is being continually engorged with and expressed of blood. Thus the tissues of the hoof are nourished as their waste is removed. Furthermore this pump function compresses and releases the venous plexus in the coronary bulge and the veins around the joints of the distal limb during movement.
This means that the blood reaches the extremity by means of gravity and heart function, and is pumped back to the thorax by the hoof mechanism. At the same time a proper metabolic state is provided. Since the heart of the horse is relatively under-sized (only .5% of body weight) these four additional pumps are mandatory for proper circulation to occur. It is a known fact that if a horse lies down for more than three days it will die. The heart alone cannot maintain the blood circulation over this period of time.
The hoof wall is very small in relation to the weight of the horse even when the horse is standing. When in movement, the degree of acceleration increases the weight, and shock absorption becomes a critical issue. How is this huge destructive impact (potential energy) neutralized and changed into a useful form of energy? This happens by way of reversible deformation of the hoof capsule for expansion under weight-bearing conditions; meaning that under weight, the hoof wall deforms 3-dimensionally, drawing the sole flat, against the resistance of firm ground. There is a considerable amount of energy present when a hoof hits the ground, ever greater as acceleration increases. L. Bein in 1983 (Zurich), through his scientific research, found that approximately 80% of the force of impact is absorbed through hoof deformation.
The deformation of the hoof capsule (hoof mechanism), the bow-shaped (leaf spring) alignment of the toe bones, the elasticity of the spiral horn tubules composing the hoof wall and the stretching of laminar horn and lamellae all play a roll in shock absorption. The quality of horn production directly influences the elasticity and shock absorption capacity of the hoof.
As a by-product heat is produced which is vital to proper hoof metabolism. On the long way from the thorax or muscled regions down to the hoof the blood cools considerably. Without the added energy of hoof mechanism the metabolic temperature in the hoof is too low.
Most of the meridians of the horse begin or end just above the coronary band. The quality of active stimulation of these meridians is determined by the healthy shape and function of the hoof and through the quality and quantity of movement.
For hoof mechanism to take place a physiologically correct, slanting cone hoof form is necessary, as illustrated in the Bucket Model (see figure). For a horse that is not living in its wild state, it is only through maintenance of correct angles and proportions by frequent, professional hoof trimming that optimal hoof mechanism can take place.
Without hoof mechanism all categories of hoof function are impaired. Plenty of movement and a natural lifestyle are absolutely necessary as well. Without almost constant movement on appropriate terrain, horn metabolism, heart/circulatory support and heat production are not taking place consistently in the hoof. With time, impaired hoof mechanism can lead to inferior-quality tissue development, risking injury and running further risk of damage if shock absorption cannot properly take place in the hoof.
About the author: