The benefits of these physiological movements within the hoof are manifold:
1. Through them shock is dispersed and the body protected from the evil consequences of concussion or shock.
2. These movements increase the elasticity of the entire limb, and in this way contribute much to a light and elegant gait.
3. They maintain a lively circulation of blood in the vessels of the pododerm, and this insures a rapid growth of horn.
Since it is a generally accepted fact that shoeing interferes with the physiological movements of the hoof, alters them, indeed, almost suppresses them, and that all these movements are spontaneous and natural only in sound unshod hoofs, we are justified in regarding shoeing as a necessary evil. However, it is indispensable if we wish to render horses serviceable upon hard artificial roads. If, in shoeing, consideration be given to the structure and functions of the hoof, and particularly to the hoof-surface of the shoe, the ends of the branches being provided with a smooth, level bearing-surface, which allows free play to the elastic horn capsule, in so far as this is not hindered by the nails we need have no fear of subsequent disease of the hoofs, provided the horse is used with reason and receives proper care.
PART II.
CHAPTER III.
SHOEING HEALTHY HOOFS.
A. Examination of a Horse Preliminary to Shoeing.
An examination should be made while the animal is at rest, and afterwards while in motion. The object of the examination is to gain accurate knowledge of the direction and movements of the limbs, of the form and character of the feet and hoofs, of the manner in which the foot reaches and leaves the ground, of the form, length, position, and wear of the shoe, and distribution of the nail-holes, in order that at the next and subsequent shoeings all ascertained peculiarities of hoof-form may be kept in mind and all discovered faults of shoeing corrected.
The examination is best conducted in the following order: The horse should first be led at a walk in a straight line from the observer over as level a surface as possible, then turned about and brought back, that the examiner may notice the direction of the limbs and the manner in which the hoofs are moved and set to the ground. While the animal is moving away the observer notices particularly the hind limbs, and as it comes towards him he examines the fore-limbs. Then a few steps at a trot will not only show whether or not the animal is lame, but will often remove all doubt in those cases in which, while the animal was walking, the examiner was unable to make up his mind as to which was the predominating position of the limb. The problem presented is, therefore, to determine whether or not the direction of the limbs, the lines of flight of the hoofs, and the manner in which they are set down and picked up are regular. If there are deviations from the normal they will fall either into the base-wide and toe-wide group or into the base-narrow and toe-narrow group. When clear upon these points the horse is allowed to stand quietly, and the observer, placing himself in front, examines the foot more closely, fixes the direction of the foot-axis clearly in his mind, marks also the form and character of the hoofs and the position of the coronets, as far as these parts can be inspected from in front. At the same time each hoof should be closely inspected to determine whether the slant of both quarters corresponds to the direction of the long pastern, and whether the course of the wall from the coronet to the plantar border is straight or bent in or out (contraction, fulness). Walls curved from above to below always indicate an unnatural height of some section of the wall and a displacement of the base of support of the foot. In order to gain accurate and complete knowledge of the position of the limbs, the flight of the hoofs, and the manner of setting the foot to the ground, the horse must frequently be moved back and forth many times, especially when the standing position is somewhat irregular and the hoofs are of different shapes.