Diseases of the Horse's Foot Part 14

_(e) Einsiedel's_.--Like the 'slipper' of Broue, the Einsiedel shoe depends for its effects upon the slope of the bearing surface.

It differs from the Broue in being provided with a 'bar-clip.' This, in addition to gripping the bars like the bar-clips of other expanding shoes, also a.s.sists, under the body-weight, in expanding the heels by the p.r.o.nounced slope given to its upper surface. The expanding force exerted by the body-weight falls thus, through the medium of the bar-clip, clip, _partly_ upon the bars, instead of, as in the Broue, solely upon the wall.

We say _partly_ advisedly, for, in addition to the slope upon the outer side of the bar-clips, the bearing surface of the heels of the shoe is _slightly_ sloped outwards also. The good office served by the bar-clip is the lessening of any tendency to strain upon the white line.

[Ill.u.s.tration: FIG. 78.--THE SLIPPER AND BAR-CLIP SHOE OF EINSIEDEL.]

Those we have described by no means exhaust the number of expansion shoes that have been devised. There are numerous others, many of which are composed of three-hinged portions, the two hindermost of which are gradually separated by a toothed arrangement of their inner margins and a travelling bar, the disadvantage of which is that it is liable to work loose. In the majority of this cla.s.s of shoe the hinges are placed far forward, one on each side of the toe. They there become exposed to excessive wear. In fact, against the bulk of this form of shoe it may be urged that they cannot be worn by the animal at work, that they are expensive, difficult to make, and easily put out of order.

3. _By Operations on the Horn of the Wall_.

_(a) Thinning the Wall in the Region of the Quarters_.--This is best done by means of an ordinary farrier's rasp. The thinning should lessen gradually from the heel for 2-1/2 to 3 inches in a forward direction. That portion of the wall next to the coronary border, about 1/2 inch in breadth, should not be touched. At this point the thinning should commence, should be at its greatest, and lessen gradually downwards until at the inferior margin of the wall the normal thickness of horn is left. The animal is then shod with a bar shoe and the hoof bound with a bandage soaked in a mixture of tar and grease, in order to keep the thinned portion of the wall from cracking. In this condition the animal may remain at light labour.

When possible, however, it is better to combine the thinning process thus described with turning out to gra.s.s. In this case the ordinary shoe is first removed, and the foot poulticed for twenty-four hours to render the horn soft. The foot is then prepared by slightly lowering the heels--leaving the frog untouched--and thinning the quarters in exactly the manner described above.

After this is done, the animal is shod with an ordinary tip, a sharp cantharides blister applied to the coronet, and then turned out in a damp pasture. In this case the object of the tip is to throw the weight on to the heels and quarters. The thinned horn yields to the pressure thus applied, and a hoof with heels of a wider pattern commences to grow down from the coronet. Two to three months' rest is necessary before the animal can again he put to work.[A]

[Footnote A: This is the treatment strongly advocated by A.A. Holcombe, D.V.S., Inspector, Bureau of Animal Industry, U.S.A.]

_(b) Thinning the Wall in the Region of the Toe_.--This is done with the idea that the tendency of the heels to expand under pressure of the body-weight is helped by the thinned portion at the toe allowing the heels to more readily open behind. Seeing that in the case of toe sand-crack the converse is argued--that contraction of the heels readily takes place and forces the sand-crack wider open--it is doubtful whether this method is of any utility in treating contracted heels.

_(c) Grooving the Wall Vertically or Horizontally, and Shoeing with a Bar Shoe_.--Marking the wall with a series of grooves, each running in a more or less vertical direction, was suggested to English veterinarians by Smith's operation for side-bones.

The manner of making the grooves, and the instruments necessary, will be found fully described in Section C of Chapter X.

That the method is followed by satisfactory results the undermentioned case will show:

'A mare, which I have had in my possession since she was a foal, has always had contracted feet, which were also unnaturally small.... Lately the mare has been going very "short," and at length her action was quite crippled.

At times she was decidedly lame on the off fore-foot. At no time have I been able to detect any sign of structural disease. I thereupon concluded that the lameness was due to mechanical pressure on the sensitive structures, and I determined to try the effects of the above treatment. As this was my first experience of the process, I was careful to carry it out in all its details, as described by Professor Smith. After the bar shoes had been put on, the mare was very lame. I allowed her two days' rest, then commenced regular walking exercise, and she daily improved. After fourteen days there was no lameness, but still short action. I thereupon gave the mare another week's walking exercise, at the expiration of which I drove her a short turn of five miles, which she did quite well, and free from lameness. For three months I kept the saw-cuts open to the coronet, and continued the bar shoes, keeping the mare at exercise, and giving her occasionally a drive. She never liked the bar shoes, and I was glad when I could discontinue them, which I did in the fourth month. When shod with the usual shoes the complete success of the treatment was shown. I have now had her going with the ordinary shoes for the past two or three months, and the improvement in the shape of the feet is very marked; there is no lameness; the mare is free in movement, fast, and spirited, whereas previously she was quite the reverse, and almost unfit to drive.'[A]

[Footnote A: W.S. Adams, M.R.C.V.S., _Veterinary Journal_, vol. x.x.x., p.

19.]

This method, though but recently introduced to the English veterinary surgeon, is by no means new. According to Zundel, it was recently made known on the Continent by Weber, but was previously known and mentioned by Lagueriniere, Brognier, and Hurtrel d'Arboval.

When the grooving is in a horizontal direction, a single incision is sufficient. This is made 3/4 inch below the coronary margin of the wall, and parallel with it, extending from the point of the heel for 2 or 3 inches in a forward direction. As in the previous method, a bar shoe is applied, and the animal daily exercised. Thus separated from the fixed and contracted portion of the wall below, the more elastic coronet under pressure of the body-weight commences to bulge. The bulging is of such an extent as to cause the new growing hoof from the top to considerably overhang the contracted portion below, and cure of the condition results from the newly-expanded wall above growing down in a normal direction.

This consideration of contracted heels may be concluded by drawing attention to the advisability of always maintaining the horn of the wall in as soft and supple a condition as is natural by the application of suitable hoof dressings.

A useful one for the purpose is that made with lard, to which has been added a small quant.i.ty of wax or turpentine.

Especially should a dressing like this be used when the hoof is inclined to be hard and brittle, and where tendency to contraction has already been noticed.

The application of a hoof ointment is also particularly indicated where the foot is much exposed to dampness, where the animal is compelled to stand for long periods upon a dry bedding, or where the bedding is of a substance calculated to have a deleterious effect upon the horn.

This, in conjunction with correct shoeing, will probably serve to avoid the necessity for more drastic measures at a later time.

_(b)_ LOCAL OR CORONARY CONTRACTION.

_Definition_.--Contraction at the heels, confined to the horn immediately succeeding that occupied by the coronary cushion. Really, the condition is but a somewhat arbitrary subdivision of contracted hoof, as we have just described it in general. For that reason we shall give it but very brief mention.

_Symptoms_.--In this case the horn of the heels, instead of running down in a straight line from the coronary margin to the bearing surface of the wall, presents a more or less distinct concavity (See Fig. 79, _a_, _a_).

As is the case with contraction considered as a whole, this deformity may affect one or both heels; and during its first appearance, which is after the first few shoeings, the animal may go distinctly lame.

_Causes_.--Coronary contraction may occur in hoofs of normal shape immediately shoeing is commenced, and frog pressure with the ground removed. It is far more likely to ensue, however, if the hoof is flat, with the heels low, and the wall sloping. And with those predisposing circ.u.mstances it is that the horse goes lame, and not with the hoof of normal shape.

Seeing, then, that this condition is largely dependent upon the shape of the foot, we may, to some extent, regard it as hereditary. Seeing further, however, that it only appears when shoeing is commenced, we may in a greater degree also regard it as acquired. The lesson, therefore, that this and other forms of contraction should teach us is the carefulness with which the shoeing should be superintended in a large stud, or in any case where the animal is of more than ordinary value.

[Ill.u.s.tration: FIG. 79.--HOOF WITH LOCAL OR CORONARY CONTRACTION (AS INDICATED AT THE POINTS _a, a_).]

The explanation of the restricted nature of this form of contraction is simple enough. We have only to refer to the lessons taught by the experiments of Lungwitz, described in Chapter III., and the condition almost explains itself. We remember that, briefly, the coronary margin of the wall resembles a closed elastic ring, which yields and expands to local pressure, no matter how slight. We remember also that removal of the counter-pressure of the frog with the ground tended to contraction of the wall's solar edge when weight was applied. Connect these two facts with the experience that this form of contraction more often than not occurs in hoofs with sloping heels, and we arrive at the following:

1. The excessive slope of the heels tends to throw a more than usual part of the body-weight upon the posterior portion of the coronary margin of the wall, with a consequent expansion of that part of the coronary margin implicated.

2. That the shoeing, in removing the counter-pressure of the frog with the ground, is at the same time tending to bring about contraction of the lower portions of the wall at the heels and quarters.

3. That this tendency to contraction will at first appear in the thinner portion of the area of wall named--namely, in that immediately below the bulging coronary margin.

We thus get the appearance depicted in Fig. 79--a contraction _(a, a)_ of the heels in the horn below the coronary margin, with the coronary margin itself bulging above, and a hoof of apparently normal width below.

We say 'apparently' with a purpose, for, as actual measurements will show, the wall near the solar edge is really contracting, for reasons which we have just described connected with shoeing. Its 'appearance' of normal width is accounted for thus: The contraction at _a, a_ is caused by the dragging inwards of the coronary cushion brought about by the sinking downwards of the plantar cushion, with which body it will be remembered the coronary cushion is continuous. With the constant dragging in and down of the coronary cushion there is given, to the horn-secreting papillae, studding both the lower third of its outer face and its lowermost surface, a distinct 'cant' outwards. Below the lowermost limit of the coronary cushion, then, by reason of the cant outwards of the coronary papillae in the situations mentioned, the horn of the wall takes a more outward direction than normal, a fact which lessens in effect the contraction as a whole really going on. It is interesting, too, to note that by this outward cant of the wall below, and the bulging of the coronary margin above it, the contraction (_a, a_) is heightened in effect, and caused to appear greater than really it is.

From what we have said it follows that contraction of the heels, excepting the extreme coronary margin, is existent generally, and not confined solely to _a, a_.

We have, then, in this condition, as we indicated at the commencement, but a phase in the evolution of ordinary contracted heels, for, with the progress of the contraction already existing at _a, a_, and below those points, it is only fair to a.s.sume that with it falling in of the at present bulging coronary margin must sooner or later occur, that, though expanded when compared with the wall below it, it will be really contracted as compared with what it was once in that same foot.

We may therefore conclude this section by remarking that factors tending to contraction of the heels in general are equally potent in the causation of contracted coronet alone.

_Treatment_.--Exactly that described for contracted heels. Bearing in mind that contracted coronary margin is but the onset of contracted heels, and that its first exciting cause is that of removal of the ground-pressure upon the frog, the most careful attention must be paid to the shoeing. The use of bar shoes, ordinary frog pads, or heelless shoes and bar pads, are especially indicated, together with abundant exercise. By these means the normal movements of expansion will be brought into play, and the condition quickly remedied.

C. FLAT-FOOT.

_Definition_.--By this term is indicated a condition of the foot where the natural concavity of the sole is absent.

_Symptoms_.--In the flat-foot the inferior edge of the wall, the sole, and the frog, all lie more or less in the same plane. It is a condition observed far more frequently in fore than in hind limbs, and is seen in connection with low heels, more or less obliquity of the wall, and a tendency to contraction. The action of the animal with flat feet is heavy, a result partly of the build of the foot, and partly of the tenderness that soon comes on through the liability of the sole to constant bruising.

[Ill.u.s.tration: FIG. 80. This figure represents the lower surface of a typical flat-foot. It ill.u.s.trates, too, the commencement of a condition we referred to in Section B of this chapter--namely, the compression of the frog by the ingrowing heels (b) and bars (a).]

_Causes_.--Flat-foot is undoubtedly a congenital defect, and is seen commonly in horses of a heavy, lymphatic type, and especially in those bred and reared on low, marshy lands. It is thus a common condition of the fore-feet of the Lincolnshire shire.

As might be expected, a foot of this description is far more p.r.o.ne to suffer from the effects of shoeing than is the foot of normal shape, and regarded in this light shoeing may be looked upon as, if not an actual cause, certainly a means of aggravating the condition. Directly the shoe--or at any rate the ordinary shoe--is applied, mischief commences. The frog is raised from the ground, and the whole of the weight thrown on to the wall. The heels, already weak and inclined to turn in, are unable to bear the strain. They _turn in_, and contraction commences. This 'turning in' of the heels is favoured by the undue obliquity of the wall. At the same time, the sole being archless, a certain amount of elasticity is lost. The weight is thrown more on to the heels, and the os pedis slightly descends, rendering the flatness of the sole even more marked than before.

With the loss of elasticity of the sole concussion makes itself more felt.

The animal is easily lamed, bruised sole becomes frequent, and corns sooner or later make their appearance.

_Treatment_.--Flat-foot is incurable. All that can be done is to pay careful attention to the shoeing, and so prevent the condition from being aggravated. In tr.i.m.m.i.n.g the foot the sole should not be touched; the frog, too, should be left alone, and the wall pared only so far as regards broken and jagged pieces.

The most suitable shoe is one _moderately_ seated. If the seating is excessive, and bearing allowed only on the wall, there is a tendency for the wall to be pushed outwards, and for the sole to drop still further. On the other hand, if the seating is insufficient, or the web of the shoe too wide, and too great a bearing thus given to the sole, then we get, first, an undue pressure upon the last-named portion of the foot a bruise, and, finally, lameness. The correct bearing should take in the whole of the wall and the whole of the white line, and should _just impinge_ upon the sole.