A Text-Book of
by A. Lungwitz and John W. Adams Copyright 1897
This is the second part in what will be a complete reprint of Lungwitz & Adams’ important ‘Textbook of Horse-Shoeing’ originally written in the 1880’s and containing some remarkably modern information. This volume goes into the greatest detail on the subject and with an intelligent clarity that belies how old it is. Coming as it did at the end of the first horse era, and well before anyone might have reasonably predicted the advent of the automobile and tractor, it is apparent how important the equine was to the whole of society. The authors, of Germany and Pennsylvania, compiled what was, at the time, to be the ultimate word on the subject. As with all of the reprints we have offered over forty years time, we trust that readers will be triggered by these words to complete their education with diligence and introspection. Just because something is old doesn’t always make it right, and of course just because something is new doesn’t make it the true culmination either. LRM
C. Lines of Flight of Hoofs in Motion.
If we observe horses moving unrestrained over level ground, we will notice differences in the carriage of the feet. Viewed from in front, or from behind, in the regular standing position of the limbs the hoofs are carried forward in a straight direction, — that is, in a line parallel with the median line of the body (Fig. 71). The toes likewise point straight forward; the hoofs alight properly (flat) on the ground. If the horse stands base-wide, the hoof is carried in a circle; from its position, which is behind and well out from the median line, the hoof passes first forward and inward until it is close to the supporting leg, and then outward to the ground (Fig. 72), where the shock is received principally upon the outer toe. The toes point either directly forward, as in the regular standing position (Fig. 72), or forward and outward as in the toe-wide position (Fig. 73). In the toe-wide position the hoof in its flight may cross the median line.
Exactly the reverse is true of the horse that stands base-narrow; in this case the hoof is moved in a circle whose convexity is outward, — that is, the hoof from its position behind, and close to the median line, is carried forward and outward and then inward to the ground (Figs. 74 and 75).
Viewed from the side, the line of flight of the hoof is determined largely by the obliquity (slant) of the foot-axis.
1. With a straight foot axis of normal slant (45º-50º, Fig. 76, A), the hoof follows the are of a circle and reaches its highest point when directly above the supporting hoof, i.e., when half-way in the stride.
2. With a straight, but acute-angled foot-axis (less than 45º, Fig. 76, B), the hoof rises rapidly, reaches its highest point before it has completed the first half of the stride, i.e., before it has passed the supporting hoof, and descending gradually in a long curve alights easily on the ground.
3. With a straight, upright foot-axis (55º or more, Fig. 76, C), the hoof rises slowly, reaches its highest point in front of the supporting hoof, from which point it descends rapidly. The gait is “choppy,” and in the saddle horse unpleasant for the rider. The length and the height of the stride are greatest in acute-angled feet; least in upright feet. Furthermore, length and height of stride are in a measure dependent on breeding, training, condition of the legs (whether stiffened by use or disease), length of the hoof and the weight of the shoe.
Many deviations in the line of flight of hoofs and in the manner in which they are set to the ground occur; for example, horses heavily burdened or pulling heavy loads, and, therefore, not having free use of their limbs, project their limbs irregularly and meet the ground first with the toe; however, careful observation will detect the presence of one or the other of these lines of flight of the foot. Irregular carriage of the feet renders a horse unsuitable for general purposes only when it is very pronounced, in which case certain troublesome conditions, such as interfering and disease of joints, are of frequent occurrence.
D. The Influence of Weight in the Shoe or Otherwise Attached to the Hoof, in Altering the Flight of the Hoof.
There is nothing mysterious in the effect of weight upon the flight of the feet. On the contrary, the lines of flight are determined (as shown in Figs. 71-76), first, by the relation of the transverse axes of the hinge-joints of the leg and foot to the line of the progression (median line); second, by the length and obliquity of the hoof and pastern; third, by the height and length of stride which is natural to each individual.
Weight induces higher action and a longer stride. Inertia increases with the weight. A heavy shoe cannot be snatched from the ground as quickly as a light one, but when moving forward at a given velocity its greater momentum (momentum=mass (wt) x velocity: m=wt x v) carries the foot farther forward than does the lighter shoe. Thus, the heavier shoe, or weight is placed, i.e., the nearer to the toe it is placed, the greater the muscular effort required to start it and to stop it.
Height of action, though largely the result of breeding, temperament, and the exhilaration that accompanies perfect health and entire absence of muscular fatigue, is to a certain extent influenced by the inclination of the pastern and toe to the cannon. The acute-angled foot, in the folding of the leg during the first half of the stride, moves through a longer are of a circle whose centre is the fetlock joint than does the normal or the upright foot; rises more rapidly and to a higher point. (See Fig. 76, B) When the momentum of a foot moving rapidly and abruptly upward is increased by weight the result is extreme and even exaggerated flexion of all joints of the leg, and by allowing the hoof to grow long the flexion is still further increased. In the show ring, harness horses with fair natural action may be made to “climb” by shoes weighing from thirty to sixty ounces upon hoofs an inch or more longer than normal. The leverage of a heavy shoe on a long hoof is excessive, fatiguing and most injurious to ligament, tendon, and muscle. The action, while high, is labored, pounding and altogether inelegant.
In training of trotters weight is often used to increase the length of the stride, or to cause a higher folding of a front foot, in order to prevent “scalping” or “speedy-cut.” As soon as the new gait becomes a fixed habit the weight should be gradually lessened. Weight is carried with less fatigue at a trot than at a pace, or at a gallop. It therefore steadies a trotter that is inclined to pace, or “break” into a run. The increased momentum of the weighted hoof makes for rhythm or movement, and increases the difficulty of skipping, dwelling, or mixing gaits.
In the base-wide (toe-wide) and base-narrow (toe-narrow) standing positions, the flight of the hoofs, as seen from in front or behind, is not straight forward, i.e., parallel to the line of progression of the body, but in arcs of circles. (See Figs. 72-75) In these cases, increasing the weight of the hoofs, by increasing the momentum, must of necessity increase the tendency of the hoofs to move off at a tangent to the curves which they describe. In other words, weight increases the centrifugal force of a body moving in a curve. The outward swing of the hoofs of a base-narrow horse (paddling), and the inward swing of a base-wide horse (interfering), are made more pronounced by adding weight to any part of the hoof. The centrifugal force is greatest in base-wide feet when the weight is on the medial, or inner side of the hoof; in base-narrow feet when it is on the lateral or outer side.
A side weight, or side weight shoe is often of service in a crossfiring pacer. This animal usually stands base-narrow (toe-narrow) behind, and in motion his hind hoofs describe a curve at first forward and outward and then inward till contact is made with the diagonal hoof or leg. The added weight (placed on the outer side) by increasing the centrifugal force carries the hoof just enough farther from the centre around which the hoof swings to prevent contact. (See cross-firing)
Finally, it must not be forgotten that weight is always weight; that it cuts speed and devours endurance.
E. Forms of Hoofs.
A front hoof of the regular standing position (Fig. 79). The inner and outer walls differ but little in direction and thickness. The outer wall is a little thicker and somewhat more slanting than the inner (see Figs. 61 and 62, Horseshoeing Part 2A), and its outer circumference describes a larger arc of a circle, — that is, is more curved, as can be seen both at its plantar border and at the coronet. The length of the quarter in relation to the length or height of the side wall and toe is about as 1:2:3. The toe forms an angle with the ground of forty-five to fifty degrees (see Fig. 68, Horseshoeing Part 2A). The direction of the wall at the toe, viewed from the side, should be parallel with the direction of the long pastern.
A hoof of the base-wide position (Fig. 80) is always awry, because the outer wall is naturally somewhat longer and decidedly more slanting than the inner (see Figs. 63 and 64). The plantar border of the outer wall describes a large arc, whose sharpest curvature is where the side wall passes into the quarter. The plantar border of the inner wall is straighter (less curved); the outer half of the ground surface (sole) of the hoof is, therefore, wider than the inner. So long as the hoof is healthy, both branches of the frog are equally developed. The wryness of the hoof depends upon the direction of the limb, therefore, a base-wide hoof should be regarded as a normally wry hoof, to distinguish it from hoofs which are wry from disease.
A hoof of the toe-wide position (Fig. 81) is distinguished from the preceding by the bending or curvature of the plantar border of the outer toe and inner quarter being often decidedly less pronounced than on the inner toe and outer quarter; therefore, two short curves and two long curves lie opposite each other; in other words, the inner toe and outer quarter, lying opposite each other, are sharply curved, while the outer toe and inner quarter, lying opposite each other, are much less sharply bent or curved. The toes are turned out. The feet are not set down flat upon the ground, but meet it with the outer toe.
A hoof of the base-narrow position is normally wry, but never so pronounced as a hoof of the base-wide position. The inner wall is but little more oblique than the outer, the difference being most noticeable at the quarters (Figs. 65 and 66). The curve of the plantar border of the wall is similar to that of a regular hoof, except that the inner side wall and quarter are a little more sharply curved in a base-narrow hoof. Occasionally the outer quarter is somewhat drawn in under the foot.
This form of hoof is most distinctly marked in animals that stand toe-narrow or are bandy-legged.
As to the forms of the hind hoofs, what has been said concerning the influence of position of the limbs upon the shape of the front feet will apply equally well to them. The hind hoof (Fig. 82) is not round at the toe, but somewhat pointed or oval. It greatest width is between the middle and posterior thirds of the sole. It usually has a strongly concaved sole and a somewhat steeper toe than the fore-hoof; viewed from the side, the angle of the toe with the ground in the regular standing position is from fifty to fifty-five degrees.
Finally, we also distinguish wide and narrow hoofs; they are not dependent upon the position of the limbs, but upon the race and breeding of the animal.
The wide hoof (Fig. 83) is almost round upon its plantar surface. Its wall runs quite oblique to the ground. The sole is but moderately concave, and the frog is strong and well developed. The narrow hoof (Fig. 84) is rather elliptical, with steep side walls, strongly concaved sole, and small, undeveloped frog. The horn of the narrow hoof is fine and tough; of the wide hoof, usually coarse. The wide hoof may readily become flat. Narrow hoof may readily become flat. Narrow hoofs are either the result of breeding or premature shoeing.
In enumerating the preceding forms of the hoof we have by no means referred to all the forms in which the hoof may be found; on the contrary, hoofs vary in shape and quality to such an extent that among a hundred horses no two hoofs can be found which are exactly alike. In fact, the same variety exists as in the faces of people, and we know that we can recall in succession even many more faces without finding two that are exactly alike. This explains the manifold differences in horseshoes with respect to size, form and other qualities.
Suppose now a hoof is before us; it is first necessary to know whether or not it is healthy. Unfortunately, a perfectly healthy hoof is not so easy to find as one may think. We recognize a sound hoof by the following marks: Seen from in front or from the side, the course of the wall from the coronet to the ground, in the direction of the horn-tubes, is straight, — that is, bent neither in nor out. A straight edge, placed upon the wall in the direction of the horn-tubes, touches at every point. The wall must show neither longitudinal nor transverse cracks or fissures. If there be rings, their position and course are important. Rings which pass around the entire circumference of the wall parallel to the coronet indicate nothing more than disturbances of nutrition of the hoof; but the hoof cannot pass for sound when the rings have any other position and direction than the one mentioned, or if the rings upon any part of the wall are more marked than elsewhere, even though they may be parallel to the coronary band. Marked ring-building upon the hoofs of horses which have regular feeding, grooming, and work indicates a weak hoof. Viewed from the ground-surface and from behind, the bulbs of the heels should be well rounded, strongly developed, and not displaced. The concave sole should show no separation along the white line. The frog should be strong, well developed, and have symmetrical branches and a broad, shallow, dry median lacuna. The lateral lacunae of the frog should be clean and not too narrow. The bars should pass in a straight direction forward and inward towards the point of the frog. Any bending outward of the bars towards the branches of the sole indicates the beginning of a narrowing of the space occupied by the frog, — that is, contraction of the heels. The horn of the branches of the sole in the buttresses and in their proximity should show no red staining. The lateral cartilages should be elastic. No part of the foot should be weakened at the cost of other parts. By firm union of all strong parts the strength and vigor of the hoof is in no sense disturbed. If one desires to ascertain the exact form and state of health of the hoof, it must never be inspected and judged alone, but in connection with the entire limb.