Horseshoeing Part 7

A Text-Book of Horseshoeing

by A. Lungwitz and John W. Adams Copyright 1897

CHAPTER IX.

DEFECTS OF THE HOOF

A. Changes of Form.

1. THE FLAT AND THE FULL HOOF (DROPPED SOLE).

(a) Flat Hoof. — A flat hoof is one whose toe and side walls are inclined very obliquely to the ground surface, and whose sole is on a level with the bearing-surface of the wall.

It exists most often in horses bred in low-lying, marshy countries.

Frequently the frog is well developed, and projects considerably beyond the level of the wall. The branches of the sole sink perceptibly under the weight of the body, much more than in better-formed hoofs:

Preparing the Hoof for the Shoe. — The rule is to spare the plantar surface of the foot. After removing from the sole what little loose horn there may be, level the usually deficient bearing-surface of the wall with the rasp. The outer border of the wall, especially at the toe, should be rounded off rather more strongly than usual, because the toe requires and will bear considerable shortening. Outward bendings of the lower border of the wall should be removed as far as it is practicable to do so.

The shoe, which should be rather wider in the web and thicker than usual, should have its bearing-surface shaped to correspond to the bearing-surface of the wall; that is, if the bearing-surface of the wall is below the margin of the sole (the sole of the foot being uppermost), then the bearing-surface of the shoe should incline downward and inward (Fig. 200, b). The bearing-surface of the branches, however, must always remain horizontal. The shoe always requires deep concaving, especially along the inner branch of the sole. If the quarters are weak, the walls defective, or there are corns, cracks, loose walls, or other diseases of the hoof, a bar-shoe should be selected.

(b) Full Hoof (Dropped Sole). — A full hoof is one whose sole instead of being concave is convex, — that is, bulges beyond the bearing-surface of the wall. It either arises gradually from a flat hoof or is the result of laminitis (founder). In full hoofs the lower surface of the os pedis is of the same shape as the horny sole.

The preparation of a full hoof for the shoe consists merely in removing all loose horn. In case the dropping of the sole is very pronounced, the bearing surface of the wall should be built up artificially with Defay’s hoof cement. The shoe should be light, but broad in the web, and furnished with a more or less deep concaving, which extends from the inner edge of the web to the outer edge of the shoe, and corresponds in shape to the bulging of the sole. By reason of the deficiency of the wall, the bar-shoe deserves the preference over an open shoe. It is frequently necessary to apply toe- and heel-calks to remove the hoof from contact with the ground. The nails should be thinner and longer than usual, and a more secure position of the shoe may be secured without injury to the hoof by drawing up two side-clips.

Flat and full hoofs are incurable. Shoeing is of benefit only in rendering such horses serviceable. Soles that are soft and sensitive should be smeared with crude turpentine or pine-tar, though unusual sensitiveness calls for a leather sole. Horses with full hoofs should not be driven faster than a walk over hard roads. During long-continued spells of wet weather softening of these hoofs should be prevented by smearing the soles with a hoof-ointment containing resin.

2. THE UPRIGHT OR STUMPY HOOF.

The upright or stumpy hoof is that form in which the quarters, with relation to the toe, are too long (too high). The wall at the toe stands very steep, in some cases perpendicular, and is strongly worn away by standing and travelling.

Causes. — 1. The upright hoof is peculiar to the “standing under” position (Fig. 53) and to the so-called bear-foot (Fig. 70).

2. It arises also as a result of all those alterations in the direction of the limbs which tend to remove the quarters from contact with the ground (contraction of the flexor tendons, spavin, — Fig. 202).

3. It may arise gradually from neglect of the hoofs of horses running barefoot.

4. It may arise from excessive shortening of the toe in relation to the quarters.

Shoeing. — The forms of hoofs mentioned in class 1 should be left as they are. The hoofs that fall under class 2 should be dressed and shod until a more natural setting down of the foot is secured. This is brought about by sparing the quarters, and applying a shoe with thickened branches or with heel-calks. Where the service of the animal is exacting and upon hard streets, the toes, especially of the hind shoes, may be made more durable by welding in steel plates. Besides, the shoe should be moderately base-wide around the toe, — that is, should be bevelled downward and outward, should have a strong toe-clip, and should be quite concave at the toe and rolled. (Figs. 203 and 204). Should the hoof tip forward whenever the weight is thrown upon the limb, a shoe with a spur projecting from the centre of the toe, and turning back and pressing upon the wall just underneath the coronary band, will be of service (Fig. 202).

Only those upright hoofs which are the result of the causes mentioned in 3 and 4 are to be dressed as ordinary hoofs, and if the service required is not too exacting they should be shod with tips (Fig. 201), or with shoes with thinned branches.

3. THE CONTRACTED HOOF.

A hoof which has deviated from its normal form in such a manner that its posterior half, either in part or as a whole, is too narrow, is a contracted hoof. The walls of the quarters assume an abnormally oblique direction downward and inward towards the median line of the hoof.

When contraction affects only one quarter, it is called unilateral contraction, or abnormal wryness (Fig. 211).

The buttresses are usually very much prolonged and press upon the frog and cause it to shrink. The bars no longer run in the natural straight direction from the point of the frog backward and outward, but describe a circle passing outward, backward, and inward.

Contraction affects front feet, especially those of the acute-angled form, more often than hind feet. In order to determine whether or not a hoof is too narrow, we should always examine the frog and its lateral lacunae. If the frog is small and narrow, and the lateral lacunae very narrow and deep, there can be no doubt but that the hoof is too narrow (contracted).

The causes, aside from too little exercise, are chiefly errors in shoeing, such as weakening the posterior half of the hoof, leaving too long a toe, either neglecting to remove the spurs of horn which grow from the buttresses and press upon the frog, or removing them incompletely, and using shoes whose branches are either too wide apart or are inclined downward and inward, so that under the weight of the body the heels are squeezed together and contraction is favored.

Prevention and Treatment. — First, it should he borne in mind that whatever exercises moderate pressure upon the sole, frog, and bars tends to expand the hoof. The action and value of the various shoes, frog-, and sole-pads, are measured by this rule. For this reason a shoe with heel-calks is never advisable if an open flat shoe without other means of relief can he used. Furthermore, since contraction is the parent of nearly all diseases of the hoof (corns, quarter-cracks, bar-cracks, thrush of the frog), we should use the greatest care to prevent it by dressing the hoof as described earlier, using flat shoes with a horizontal bearing-surface for the quarters, giving abundant exercise, preventing drying out of the horn, and allowing the animal to go barefoot whenever possible. Where the contraction is but slight the foregoing rules will be found sufficient.

In very pronounced contraction, where the hoof is not acute-angled, an expansive shoe with clips raised at the ends of the branches to press against the buttresses may prove very advantageous; but under no conditions should violence be used in expanding the heels with the expanding-screw. This is an act of extreme delicacy, and should be performed only by experienced veterinarians.

In very pronounced contraction of one or both quarters of hoofs of every degree of obliquity we may obtain a continuous expansive action by the use of one of the numerous V-shaped springs, of which the Chadwick spring is the best (Fig. 207 and 208). After levelling the wall and thinning the branches of the sole, the points of the spring are set against the buttresses, the apex of the spring moved to and fro till the points have bored well into the horn, when the apex is laid against the sole at the toe, the sole filled with tar and oakum and covered by a leather sole, and a bar-shoe applied. If the contraction be less pronounced, or if the frog be much shrunken we may place a Chadwick spring beneath a rubber bar-pad with a short shoe. The spring may be stiffened from shoeing to shoeing, first by introducing the ferrule at the apex of the spring and later by shifting the ferrule toward the shoulder (Figs. 207, b, and 208, b).

For contracted hoofs of the acute-angled form we use the bar-shoe, and if there are other diseases of the hoof present, or if we wish a more rapid and continuous expansive action, we use also a leather sole with foot-packing with or without a buttress spring. A foul frog should be properly cleansed, and then disinfected with pine-tar thinned with alcohol or crude wood-vinegar (pyroligneous acid).

Further curative measures are: turning the horse out without shoes (expensive and seldom practicable); applying tips; using shoes the bearingsurface of whose branches inclines downward and outward (unilateral contraction requires but one branch to be so constructed); hoof-pads of rubber (Figs. 145, 146, and 147), straw, rope, cork, hoof-cement, etc. Special forms of contraction are distinguished, and are as follows:

(a) The Contraction of Wide Hoofs. — This contraction is manifest as a concavity or groove in the wall just below the coronet, usually at the quarters, though sometimes extending entirely around the foot parallel to the coronary band (Fig. 209). Pain is produced in the contracted area by lightly tapping the horn, but not by moderate pressure with the hoof-testers.

Green horses with wide hoofs, just from the pasture, are particularly liable to this form of contraction. As a rule, the lameness does not disappear completely until the wall has assumed its natural, straight direction by growing down properly from the coronary band.

In dressing the hoof and applying the bar-shoe, care must be taken that the lower border of the wall underneath the painful area is lowered so much that it will not receive direct pressure from the shoe.

(b) Contraction of the Sole. — This is accompanied by an unnatural direction of the wall. Instead of the wall being straight from the coronet to the shoe, it describes a curve whose convexity is outward (keg-shaped, claw-shaped when seen from the side) (Fig. 210). The hoof seems constricted (tied in) at the coronet and at its plantar border, the sole is abnormally concave (arched), and the plantar surface of the hoof is considerably shortened from toe to heel. It happens in both shod and unshod horses, with otherwise strong hoofs, but is quite rare. It is occasionally associated with navicular bursitis (“navicular disease”).

Causes. — Principally dryness, too little exercise, and shoes without horizontal bearing-surface.

The treatment is correspondingly simple: The shoes should be flat, fitted full all around to coax the wall out at every point, and the outer border bevelled base-wide, so as to furnish a base of support that is wider and longer than the hoof. In moderate contraction of the sole, the bearing-surface of the shoe should be perfectly horizontal, but if the contraction be very pronounced, the entire bearing-surface should incline downward and outward (even at the toe). No toe- or side-clip should be used. The shoe should be reset every two weeks; the sole kept so thin by paring that it will spring under thumb pressure, and kept moist by washing, tubbing or “stopping,” and the animal given moderate exercise daily.

In all forms of contraction of the hoof abundant exercise and the maintenance of the natural pliancy of the horn by daily moistening (washing) with water are absolutely necessary for successful treatment.

4. THE WRY HOOF.

If one side wall and quarter is steep, and the other very slanting or oblique, we term such a hoof a “wry hoof.” Such a hoof divided in the middle line presents two very dissimilar halves. There are three classes of wry hoofs: 1, normal wry hoofs (see Figs. 63-66); 2, pathological wry hoofs, or hoofs contracted in one quarter (see contracted hoofs); 3, wry hoofs which are the result of improper shortening of the wall and of neglect in horses running barefoot.

Only the second and third classes of wry hoofs require especial attention. First, the more oblique wall must be cut down, and the steep wall spared, — a procedure which differs essentially from that employed in treating the first class, but is, nevertheless, entirely warranted, because these second and third kinds of wry hoofs do not correspond to the direction of the limb.

In order to take weight from the steep wall, we use with advantage a bar-shoe, which should be longer and wider than the hoof on its contracted side. In other words, enlarge the base of support by making the branch of the shoe broader. If an entire side wall and quarter is contracted the branch of the shoe beneath must be broad, the border bevelled base-wide, and the branch punched so deeply that the nail-holes will fall upon the white line.

In old work-horses any sort of shoe may be used, though a flat shoe serves the purpose best. If a hoof is wry from faulty paring, and we cannot at once completely restore the proper relative slant of the two walls by paring alone, we may use a shoe with a thicker branch for the half of the hoof which is too low (too steep).

In colts such wry hoofs can often be cured only by shoeing. The shoe employed for this purpose is so made that the branch underneath the steep (contracted) wall is quite thick, but gradually thins away around the toe to the end of the other branch. In strongly marked cases the thin branch may end at the middle of the side wall (a three-quarter shoe). This method of shoeing shifts the body-weight upon the slanting wall and restores the foot to its proper shape in from two to four shoeings.

Causes. — Unequal distribution of the weight in the inner and outer halves of the foot, in conjunction with excessive cutting down or wear of the steeper wall. All faults in shoeing which tend to produce contraction of the heels aid in the formation of a wry foot, especially when these faults directly affect the steep wall. Neglect of the colt’s hoofs during the first years of life frequently lays the basis for wry foot in later years. All wry feet are more susceptible to disease than others.

The amount or degree of wryness varies considerably. In a moderately developed case the steep wall (usually the inner) will be drawn in at the plantar border of the quarter, presenting a convex surface between this border and the coronet, and the adjacent branch of the frog will be more or less shrunken. In extreme cases the slanting wall (usually the outer) will also be involved and bent in the opposite direction, — i.e., will be concave (dished) between coronet and lower border (crooked hoof).

Prognosis. — When the degree of wryness corresponds to the slant of the foot-axis and the old shoe shows nearly uniform wear, the defect is not directly injurious. In very pronounced “wryness,” however, with thin, bent walls, a number of associated lesions, such as corns and cracks, may be present and render the animal unfit for service upon paved or macadam roads.

5. THE CROOKED HOOF.

A crooked hoof (Fig. 212) is one whose walls (viewed from in front or behind) do not pass in a straight, natural direction from the coronet to the ground, but are bent in such a manner that the bearing-surface of the wall in relation to the foot axis lies either too far out or in.

It may occur on any foot, but is seldom strongly marked.

Causes. — The causes are either long-continued leaving of one-half of the wall too high, or the use of shoes shaped for normal feet upon hoofs of the base-wide position.

The principal part of the treatment is the proper dressing of the hoof. The wall which is bent out at the middle and drawn in at the plantar border is, as a rule, too high and too near the centre of the foot (too narrow); the opposite wall, on the contrary, is too low and too far from the centre of the foot (too wide). This explains the manner in which the hoof should be cut down and rasped. The shoe must be laid out as far as possible towards the side which is too high and narrow. A straight edge placed against the high wall touches it only at its middle. The distance of this line from the lower edge of the wall shows us how far the surface of support — namely, the shoe — should be set out beyond the horn. If the straight edge be placed against the opposite wall, it will touch only at the coronet and at the plantar border, showing that the wall is concave. The distance of the middle of this wall from the straight edge shows us how much too wide this half of the wall is at its plantar border, and how much of the outer surface of the wall at its plantar border should be removed with the rasp. The restoration of a crooked hoof to its normal form requires several shoeings.

6. OSSIFICATION OF THE LATERAL CARTILAGE (SIDE-BONE).

The ossification of a lateral cartilage (Fig. 213) consists in a change of the cartilage into bone. Heavy horses are more frequently affected than lighter ones. It most often involves the outer cartilages of the forefeet, seldom both cartilages. Side-bones always interfere with the physiological movements of the foot, and may, indeed, entirely suppress them.

The disease can only be diagnosed with certainty after the upper part of the cartilage has ossified. The coronet is then rather prominent (bulging), and feels hard. The gait is short and cautious, and well-marked lameness often follows severe work. As causes, may be mentioned predisposition in heavy lymphatic horses, and violent concussion or shock due to fast work upon hard roads. The disease is incurable.

A special method of shoeing is only necessary when the outer cartilage is ossified and the quarter upon that side is contracted. After removing the old shoe, whose outer branch is, as a rule, more worn away than the inner, the outer wall will always be found too high, due to the fact that there has been little or no expansion and contraction in this quarter and, therefore, little or no wear of the horn against the shoe. The hoof is therefore wry, — on the outside too high, and on the inside too low. This shows us how the foot should be dressed so as to obtain a proper base of support and a uniform wear of the shoe. The most suitable shoe is a flat shoe, whose outer branch must be wider than the inner. It is so applied that the inner branch follows the edge of the wall closely, while the outer branch must be full and at the quarter must extend beyond the wall far enough to touch a perpendicular line dropped from the coronet (Fig. 215). The shoe must, therefore, be punched deep (coarse) on the outer branch and fine on the inner. A side-clip must be placed on the outer branch, because in time, the outer half of the hoof will again be too high. Bar-shoes and rubber-pads are injurious when both cartilages are ossified, but may be used when there is partial ossification of but one cartilage, especially if corns are present.

B. Disturbances of Continuity of the Hoof.

1. CRACKS.

Interruptions of continuity of the wall extending in the direction of the horn-tubes are known as cracks or seams. They have, according to their location, degree, and extent, not only various names, but also a varying significance.

Occurrence. — On the inner side of front hoofs, especially of horses that stand base-wide; on hind hoofs, usually at the toe.

Classification. — According to location we distinguish toe-cracks, side-cracks, quarter-cracks, and bar-cracks. Those cracks which affect only the upper border of the hoof are called coronary cracks; those which are limited to the lower border of the hoof are sometimes designated low cracks (plantar cracks); while those which are continuous from one border to the other are called complete cracks. If the crack passes through the entire thickness of the wall to the sensitive tissues underneath, it is called a deep or penetrating crack, in contradistinction to the superficial crack (Fig. 216).

Causes. — There are many. Besides wounds of the coronet, everything that impairs the elasticity of the horn, weakens the hoof, and causes an overloading of one-half of the hoof. Furthermore, great dryness and excessive work on hard streets.

Prognosis. — This will depend upon the age, kind, and location of the crack. A low crack is without significance unless it is the remnant of an old coronary crack which has grown down. Coronary cracks, on the contrary, are more serious because of the lameness which often accompanies them, and especially on account of the long duration of the healing process.

The borders of the crack never grow together, and healing can only take place through healthy, unbroken horn growing down from the coronary band.

(a) Treatment of Coronary and Bar-Cracks. — If practicable, allow the affected horse to go barefoot; otherwise, the use of the bar-shoe for all cracks is advised, because it will continuously protect the diseased section of wall from pressure by the shoe. If there are present still other diseases of the hoof (corns, contraction, flat or full hoof), the addition of a leather sole with packing will be most beneficial, not only in favoring the healing of the crack, but also in improving the form of the hoof and in favoring the cure of the other lesions. In all coronary cracks it is of advantage to assist healing by fastening or immobilizing the borders of the crack by one of the following methods:

1. By rivets (nails), which pass across the crack through holes previously drilled in the horn (Fig. 217).

2. By clamps or hooks, which by means of special pincers are forced into pockets previously burnt into the horn on opposite sides of the crack (Fig. 219, B).

3. By a thin iron plate placed across the crack and secured by small screws, such as are used in wood (Figs. 220, 221).

4. By means of a bandage to last one shoeing.

Toe-crack occurs most often in draught-horses and most frequently in the hind feet. In shod hoofs it starts at the coronary border, and unless proper treatment is instituted soon reaches the plantar border. Long toes and low quarters and excessive dryness of the horn are predisposing causes. The exciting cause is usually forward pressure of the upper end of the short pastern against the thin upper edge of the wall of the toe. In the last part of the phase of contact of hoof with ground the pasterns are upright, or may even incline downward and backward (foot axis broken strongly backward), the short pastern presses the coronary band firmly against the upper thin edge of the toe, when if brittle through dryness it is unable to stretch and tears asunder. Thus, under the effort of starting a heavy load, when a horse with all four legs flexed has risen upon the points of his toes, a short quick slip followed by a catch, will frequently start a crack at the coronet.

The hoof should be so dressed and shod that the foot-axis shall be straight when seen from the side. In hind feet it is admissible to break the foot axis slightly forward. Therefore, shorten the toe and spare the quarters. If the latter are deficient in length, raise them by swelling the branches or by low heel-calks.

The shoe may be open, or a bar-shoe, or a short shoe with a rubber frog and buttress-pad. Whatever expands the quarters closes a toe-crack. The Defay’s shoe (Fig. 206), or the Chadwick spring beneath a rubberpad, or beneath a bar-shoe with leather sole, if the frog be much shrunken, will be of service. The shoe should fit air-tight, except for an inch or so on both sides of the crack. Two lateral toeclips (Fig. 217) are drawn up, and the wall between these clips is cut down from a twelfth to an eighth of an inch.

After the shoe has been nailed on tight the toe-crack should be immobilized. The best method is by buried nails. Slots are burned or cut on opposite sides at a distance of an inch from the crack. With a spiral drill (see Fig. 218) bore a hole from a slot at right angles to the crack. Make a similar hole on the opposite side. Make the holes continuous by introducing a straight hot wire. The rivet may be an ordinary round wire nail which has been softened by bringing it to a yellow heat and allowing it to cool slowly. It is driven through and the ends firmly clinched. Such a nail is easily placed, need not press upon fleshy leaves, can not be stripped off or lost, and holds fast. The horse should stand on the foot while the rivet is being clinched. Two are sufficient for a complete crack (Fig. 217).

A more rapid, though less efficient method of immobilizing a toe- or a quarter-crack is by the use of the Vachette hook. A special apparatus is required (see Fig. 219). The burning iron (Fig. 219, A) is brought to a yellow heat, its end applied to the wall so that the two ears are on opposite sides and equidistant from the crack, when it is pressed firmly till the shoulder (Fig. 219, b) touches the surface of the wall. A Vachette hook, the distance between the points of which equals the distance between the ears of the firing iron, is seized by the special pincers (C), pressed into the slots burned to receive it, and is then driven into the horn by compressing the pincers. At the toe these hooks are frequently stripped off by the heels of the opposite shoe (in hind feet). Free application of hoof ointment, and maceration of the horn by melting snow or mud tends to loosen them so that they often drop out.

An efficient method of fastening either a toe- or a quartercrack is by using a metal plate one-sixteenth (1/16”) of an inch thick, provided with four to eight holes for the reception of screws four- to five-sixteenths of an inch long. The plate is heated, bent to conform to the curvature of the wall and pressed against the horn till it burns a bed for itself, when it is screwed fast. It will not loosen (see Fig. 220, b). In every complete crack of the wall the growing down of coherent horn is favored by thinning the horn for an inch on both sides of the crack directly over the coronary band (see Fig. 221, a), so that any gliding movement between the sides of the crack below can not be transmitted through the thinned area to the crack in the velvety tissue of the coronary band. Cutting a “V” at the coronet acts similarly, but is less efficient.

Quarter-crack is usually associated with contraction of the heels. It occurs on the inner quarter of base-wide (toe-wide) hoofs, and rarely in the outer quarter of base-narrow hoofs. For quarter-cracks we use a bar-shoe and determine the extent of the wall to be laid free in the following manner: We imagine the crack to be prolonged in the direction of the horn tubes to the plantar border, and drop a perpendicular line from the upper end of the crack to the plantar border. That part of the plantar border lying between these two points is then to be lowered sufficiently to prevent pressure from the shoe until the next shoeing (Figs. 220, a, and 221, c).

This method should be followed even when the perpendicular line falls behind the buttress.

The crack may be immobilized by the metal plate, or by narrow ticking bandage or adhesive tape wound a half dozen times around the hoof, in conjunction with a bar-shoe, Chadwick spring, leather sole and tar and oakum sole-packing.

In dressing the hoof, the side containing the crack should be spared, the opposite side lowered, the object being to shift the weight and consequent expansion into the sound quarter. When the affected quarter is deficient in length the branch of the shoe beneath should be made thicker, even to the extent of causing it to ground in advance of the opposite branch.

Next to shoeing, rubber hoof-pads render good service, because through them a part of the body-weight is distributed over the sole and frog. They assist in widening the hoof, and lessen shock when the foot is set to the ground. These are all matters which favor the growing down of unbroken horn.

When the crack gaps widely, and the frog is small and deep in the foot a shoe with bar-clips (Defay’s shoe), or a Chadwick spring, with bar-shoe and leather sole may be used. It is not impossible, indeed, to obtain a cure by using an ordinary open flat shoe, though much will depend upon the other lesions that may be present, the nature of the hoof, and the service required of the animal.

If the edges of the crack are irregular and overlapping, they should be carefully thinned away. Thinning the horn on both sides of the crack over the coronary band, preventing drying out of the horn, and frequent applications of carbolized oil to the coronet favor growth of undivided horn and guard against a renewal of the crack.

If in the beginning of the disease there is inflammation and lameness, cooling poultices should be used for several days. When there is no lameness, the horse may be used for slow draft purposes. Coach- and saddle-horses should be kept from fast work until sound horn has grown down at least one-half of an inch from the coronet.

Bar-cracks are usually the result of changes of position of the quarters, and are just as frequently brought about by contraction as by leaving the quarters too high. We see them almost entirely upon the fore-hoofs. They seldom occur alone; but are usually accompanied by corns. When the crack extends to the pododerm there is a superficial inflammation of the pododerm and lameness. When treatment is not promptly begun the inflammation extends to the deeper layers of the pododerm, or, indeed, even to the plantar cushion, and gives rise to swelling of the bulb of the heel upon that side and to a well-marked lameness, which requires treatment by a competent veterinarian.

Ordinarily a bar-crack is only found by a close examination of the hoof after the shoe has been removed. In paring the hoof the crack usually appears as a dark streak, sometimes as a bloody fissure; not infrequently grayish hoof-pus is discovered in the depths of the crack.

The treatment must be directed towards favoring the growth of a continuous (unbroken) bar. This is accomplished by completely removing the edges of the crack, paring the horn of the vicinity very thin, and preventing the least pressure upon the wall of this quarter by the shoe, by lowering this quarter with the rasp and applying a bar-shoe with leather sole.

Following the removal of the edges of the crack there often appears, especially in stumpy hoofs, a deep groove; if the bottom of this groove is moist, we should pack it with oakum wet with a five per cent. solution of creolin or carbolic acid, and cover the oakum with wax (grafting wax). The cracks will return if the exciting causes cannot be completely removed.

(b) Treatment of Low Cracks (Plantar Cracks). — These cracks, occurring principally upon the hoofs of unshod horses, are the result of excessive sketching and bending of the lower border of the wall. Insufficient rounding of the wall with the rasp is largely responsible for them. An exciting cause in shod horses is the use of too large nails in shoes that are punched too fine.

Every coronary crack becomes in time a low or plantar crack, and this has an important bearing upon the prognosis, because a renewal of the coronary crack will be followed by a low crack.

In order to remove these cracks it is sufficient merely to shoe the horse. Upon shod horses they may be prevented by using properly punched shoes and thin nails. The lower border of the wall near the crack should be relieved of pressure by cutting out a half-moon-shaped piece of horn. To prevent the crack from extending farther upward we may burn a transverse slot at the upper end of the crack, in as far as the leafy layer of the wall, or cut such a slot with a small hoof-knife.

2. CLEFTS.

An interruption of continuity of the wall, at right angles to the direction of the horn-tubes, is called a cleft.

Clefts may occur at any part of the wall; yet they occur most often upon the inner toe and inner side, as a result of injury from sharp, improperly placed heel-calks. However, suppurating corns, or other suppurative processes situated at the coronet or which find their point of escape at the coronet, may from time to time lead to separations of continuity and the formation of horn-clefts.

Horn-clefts, though the result of lesions which are often very injurious and interfere with the use of the horse, are of themselves not an evil which can be abolished or healed by shoeing, although, in many cases, proper shoeing would have prevented them. A horn-cleft is not a matter for consideration by the shoer until it has grown down so far that it comes within the region of the nails.

In order not to disfigure the hoof unnecessarily, the horn below the cleft should be kept in place as long as possible by shortening the wall at that point, to remove shoe-pressure, and by driving no nails into it. If, however, the horn is loose and about to come away, it should be removed and the defect filled with Defay’s patent horn-cement.

3. LOOSE WALL.

Separation of the wall from the sole in the white line is called loose wall (Fig. 223, a).

Occurrence. — Frequent on the fore-hoofs of shod and unshod horses, and oftener upon the inner than upon the outer side. More rare on hind hoofs. Common-bred horses with wide and flat feet are predisposed to this trouble.

We distinguish superficial and deep loose wall; only the latter requires the shoer’s attention, because it leads to lameness.

Causes. — Walls which are very oblique (slanting); outward bendings of the plantar border of the wall; burning the horn with hot shoes; dryness; neglected shoeing; excessive softening of the horn with poultices, particularly of cow-dung; carelessness in preparing the bearing-surfaces of hoof and shoe in shoeing; uneven fitting of the shoe.

Treatment. — It aims to remove the lameness and to favor growth of coherent horn. In the first place the removal of the exciting causes, followed by proper shortening of the wall. We should apply a shoe whose bearing-surface inclines slightly downward and inward, is perfectly smooth, and wide enough to cover the wall, white line, and outer border of the sole; the iron should be only moderately warm. Where there is lameness we use a leather sole with packing, or a bar-shoe. The loose wall should be freed from shoe-pressure only when it does not extend far along the white line. When the separation is extensive the loose wall should not be lowered. The crack should be filled with wood-tar, crude turpentine, or soft grafting-wax.

If a loose wall occur upon the foot of a horse while running barefoot, all separated horn should be removed; if, on account of the nature of the ground, this seems to be impracticable, the hoof must be shod.

Care of the Hoof. — Shoe at least every four to five weeks. Preserve the pliancy and toughness of the horn by judicious moistening.

4. HOLLOW WALL.

A hollow wall is one in which a separation has occurred between the middle layer of the wall and the keraphyllous layer. This crack or separation always extends in the direction of the layers of the wall (Fig. 223, b).

Occurrence. — Quite rare.

We should suspect a hollow wall when a part of the wall rounds out prominently beyond the rest, and gives forth a hollow (resonant) sound when struck. The white line presents a crack, yet we should hesitate to form a conclusion as to the extent of the separation from the extent of the crack along the white line, since the latter may be considerably smaller. The separation extends higher up the wall than in the case of loose wall, frequently to the coronet. The cavity is usually filled with crumbling, disintegrated horn.

Hollow wall is not often accompanied by pain. Lameness may arise, however, if the hollow section of wall assists in bearing the body-weight, and if the animal does fast work upon paved streets.

Causes. — Mechanical influences resulting in chronic inflammation of fleshy leaves.

Treatment. — A cure is possible, but requires considerable time. In shoeing, which should always aim to relieve pressure from the hollow section of wall, we cleanse the cavity and fill it with oakum and tar, crude turpentine, or wax. Where the separation is very extensive we use a bar-shoe.

The time required for complete cure of hollow and loose walls will depend upon the height of the separation.

5. THRUSH OF THE FROG.

When the horny frog is ragged and fissured, and an ill-smelling, dark-colored liquid collects in the lacunae of the frog, it is affected with thrush. When thrush exists uninterruptedly for several months the perioplic band is irritated and forms rings of periople which assume an irregular course and cross the rings of the middle layer of the wall (Fig. 224).

The causes: uncleanliness, too little exercise in fresh air, excessive paring of the frog, and the use of shoes with calks by which the frog is permanently removed from the ground.

The consequences are, besides contraction of the hoof, soreness in travelling, a shortening of the step, and, occasionally, well-marked lameness.

Treatment. — Removal of all greasy horn from the frog, and of the prominent overgrown angles of the buttresses, thorough washing of the frog once or twice daily with a 5 per cent. creolin or carbolic solution, abundant exercise, and shoes without calks.

CHAPTER X.

Shoeing Mules, Asses & Oxen

1. The shoeing of mules and asses is, as in the case of horses, a necessity if these animals are to be used for draft or saddle purposes on hard streets. The structure and characteristics of the hoofs of these animals are quite similar to those of the horse, differing chiefly in the form and thickness of the wall. The mule hoof is long and narrow and round at the toe, the sole is well arched, and the side walls are rather steep (Fig. 225). In the ass the narrowness of hoof is still more pronounced, the wall is relatively thick, the frog is particularly well developed in its branches, and therefore the hoof is relatively wide in the region of the quarters. The horn of both mule and ass is tough.

The shoes differ from those of the horse in no other respect than that they should be lighter and narrower. Four nail-holes are sufficient for an ass’ shoe, and five to six for a mule’s. On account of the hardness and toughness of the walls, we use nails that are short but strong in the shank; nails with weak shanks are apt to bend in driving.

2. The shoeing of oxen is essentially different from that of horses, because the foot of the ox is cloven (split), the long pastern, short pastern, and hoof-bone are double, so that, instead of one hoof or claw, there are two upon each foot, distinguished as outer and inner. Each claw consists of wall, sole, and bulbs; the frog is absent. The wall is considerably thinner than that of the horse’s hoof, the sole is thin, and the bulbs are low. For these reasons the shoe designed for a claw must be thin, but wide.

The holes must be punched fine and the nails be quite short and strong. On each shoe a long tongue should be made on the inner edge near the toe, and so directed that it can be turned upward and outward to embrace the toe of the claw. A small clip raised on the outer toe of each shoe will increase its stability. In some parts of Saxony the shoes are so made that the tongue of each shoe begins in the rear third of its inner edge and runs forward, upward, and outward, closely embracing the wall of the toe. The smaller clip is drawn up on the outer edge of the shoe close to the toe. These shoes are more difficult to make, but when applied sit more firmly and remain fast longer than all others. Machine-made ox shoes (Fig. 227) have no clip at the inner toe, and are frequently pulled and lost. For this reason they are inferior to hand-made shoes. An undivided shoe (the so-called “closed claw-shoe”) is unsuitable for oxen, because it deprives both claws of their natural, free movements. However, such a shoe is of advantage for heavy draft over hard and very rough roads, because it lessens the liability of the fetlock and coronary joints and the cleft of the claws to strains.

Great difficulty is often encountered in holding the feet during the operation of shoeing. It is necessary to fasten the head securely against a tree, post, or wall. A front foot may be raised and held by passing a slip-noose in the end of a rope or side-line around the fetlock and carrying the line over the withers to the opposite side, where it is held by an assistant. A hind limb may be controlled by passing a round pole in front of the hock of the leg to be raised, and, with a man at each end of the pole, carrying the limb backward and upward, in which position it is held; or the limb may be bent and controlled by tightening a twitch or tourniquet upon the leg just above the hock (Fig. 228). Oxen that continue to resist may sometimes be quieted by light blows of a short stick upon the base of the horns. In parts of the country where many oxen are shod stocks are in common use.

Very satisfactory stocks have been designed by Gutenaecker, of Munich (Fig. 229). The four corner-posts (a, a, b, b) are eight inches square and eight feet long, of which three feet four inches are solidly implanted in the ground. They are united by side- and cross-bars (c, c, d). In front of the corner-posts (a, a) and in the middle line stands a head-post (e) of the same dimensions as the corner-posts, provided with a slot four inches wide and twenty inches long beginning three feet from the ground. In this slot is a pulley-wheel (i), and below it a windlass (k) for winding up the rope which is tied around the base of the animal’s horns. The corner-posts are provided with a slot (n) three inches wide and three inches deep, within which are placed two movable side-bars (o, p), which can be set at desired heights and fastened by iron pins. Between the front and rear corner-posts of the right-hand side is an eight-sided roller with a ratchet and click at one end, and having on one of the sides six iron hooks, to which a girth is attached. On the opposite side of the stocks, at the same height, is a stationary bar (f) with six hooks (g, g) on the outer side. The belly girth is six feet long, six inches wide, and terminates at both ends in several strong cords two feet four inches long with iron rings at their ends. Between the front corner-posts are a neck-yoke (h) and a breast-bar which slide in the slots (m) and may be fixed at desired heights by iron pins. On the rear face of each rear corner-post is an iron bracket (s) one foot and a half long, with a ring (t) six inches in diameter; through which passes a round pole padded in the middle and kept in place by two iron pins. Above each bracket is a hook (u) to which the end of the breeching attaches.

Before an animal is brought into the stocks the neck-yoke is raised, the breast-bar lowered, and the girth left hanging from the hooks on the stationary bar. The ox is then led into the stocks and the rope which is tied around the base of the horns is carried over the pulley (i), fastened to the hook on the roller (k), and wound up till the head is tight against the head-post. The yoke and breast-bar are then placed in position and fastened, the breeching hung on the hooks (u), and the belly girth attached to the hooks on the roller, so that, if need be, it can be shortened till it bears the animal’s entire weight.

To control a front foot a slip noose is placed about the fetlock and the limb is raised and lashed to the sidebar, the rope passing finally to the hook (r). To control a hind foot a slip noose is placed about the fetlock, the foot carried upward and backward over the rear cross-bar, and, with the front surface of the fetlock-joint resting against the padding of the bar, the limb is firmly secured by wrapping the line several times about the limb and bar.

When no stocks are at hand, we may use an ordinary farm wagon or a truck wagon. Tie the ox with his head forward between the front and hind wheels. Fasten the large end of a binding pole to the spokes of the front wheel and let it rest on the hub. Swing the pole close to the ox and induce him to step over it with one hind leg, then raise the rear end of the pole, and with it the leg and so much of the animal’s hind quarters that the inner hind leg standing close to the wagon rests but lightly upon the ground. The binding pole may then be slung with a rope from the rack of the wagon or other stationary object and the outer limb held in the usual manner. By following this method a shoer with one assistant can easily and safely control the most refractory oxen.