Dollar Weekly Mirror

[From Jennings on the Horse, and his diseases. Horse Shoeing and Diseases of Horses Feet.]

SHOEING

The horny sole covers the whole interior surface of the foot excepting the frog. In a well-formed foot it presents an arched appearance, and possesses considerable elasticity, by virtue of which it ascends and descends, as the weight above is either suddenly removed from it or applied to it.—This descending property of the sole calls for one especial consideration in directing the form of the shoe; for, if the sole be so formed that the horny shoe rests upon it, it cannot descend lower; and the sensitive sole above, becoming squeezed between the edges of the coffin-bone and the horn, produces inflammation, and perhaps abscess.—The effect of this squeezing of the sensitive sole is most commonly witnessed at the angle of the inner heel, where the descending heel of the coffin-bone, forcibly pressing the vascular sole upon the horny sole, contuses a small blood-vessel, and produces what is called a corn, but which is in fact a bruise.

The horny frog occupies a greater part of the triangular space between the bars, and extends from the hindermost part of the foot to the centre of the sole, just over the point where the bars meet, but is united to them only at their upper edge; the sides remain unattached and separate, and form the channel called the commissures.

If we carefully observe the form and size in the frog in the foot of a colt of from four to five years old, at its first shoeing, and then note the changes that it undergoes as the shoeings are repeated, we shall soon be convinced that a visible departure from a state of health and nature is taking place.—At first it will be found large and full, with considerable elasticity: the cleft oval in form, open, and expanding, with a continuous, well-defined, and somewhat elevated boundary; the bulbs at the heels fully developed, plump and rounded; and the whole mass occupying about one-sixth of the circumference of the foot. By degrees, the fullness and elasticity will be observed to have diminished; the bulbs at the heels will shrink, and lose their plumpness; the cleft will become narrower, its oval form disappear, the back part of its boundary give way, and it will dwindle into a narrow crack, extend back between the wasted, or perhaps obliterated, bulbs, presenting only the miserable remains of a frog, such as may be seen in the feet of most horses long accustomed to be shod.

The bones proper to the foot are three in number,—viz., the coffin bone, the navicular bone, and the part of the coronet bone; they are contained within the hoof, and combine to form the coffin joint: but the smallest of them, the navicular bone, is of far more importance as connected with the subject of shoeing, than either of the others; for upon the healthy condition of this bone, and the joint formed between it and the tendon, which passes under it to the coffin bone, and is called the navicular joint, mainly depends the usefulness of the horse to man.

This small bone, which in a horse sixteen hands high, measures only two and a quarter inches in its longest diameter, three-fourths of an inch in the widest part of its shorter diameter, and half an inch in thickness at the centre, its thickest part, has the upper and under surfaces and part of one of the sides overlaid with a thin coating of gristle, and covered by a delicate secreting membrane, very liable upon the slightest injury to become inflamed; it is so placed in the foot as to be continually exposed to danger, being situated across the hoof, behind the coffin bone, and immediately under the coronet bone; whereby it is compelled to receive nearly the whole weight of the horse each time that the opposite foot is raised from the ground.

The coffin bone consists of a body and wings, and is fitted into the hoof, which it closely resembles in form. Its texture is particularly light and spongy, arising from the quantity of canals or cells that traverse its substance in every direction, affording to numerous blood-vessels and nerves, a safe passage to the sensitive and vascular parts surrounding it; while the unyielding nature of the bone effectually protects them from compression or injury, under every variety of movement of the horse.