PART III.
CHAPTER VII.
GENERAL REMARKS CONCERNING THE SHOEING
OF DEFECTIVE HOOFS AND LAME HORSES.
The boundary between health and disease of the hoof is difficult to determine, especially when we have to deal with minor defects of structure or shape of the hoof. Ordinarily, we first consider a hoof diseased when it causes lameness. However, we know that diseases of the hoof may exist without lameness. Therefore, a hoof should be regarded as diseased or defective when the nature of the horn, the form of the hoof, or the parts enclosed by it, deviate from what we consider as normal or healthy ([see page 81]), whether the service of the animal is influenced by it or not.
Front hoofs become diseased or defective more readily than hind hoofs, because they bear greater weight, have more slanting walls, and are more exposed to drying influences. All normally wry hoofs and acute-angled hoofs become more readily diseased than regular and upright (stumpy) hoofs.
The indications of the various diseases of the hoof are discussed in the following chapters. We shall in this chapter undertake only a brief general discussion of inflammation of the pododerm. This inflammation, known as pododermatitis, always manifests itself by lameness and, under closer examination of the foot, by increased warmth, pain, and stronger pulsation of the digital and plantar arteries. The pain produces either a timid, shortened (sore) gait, or well-marked lameness, especially upon hard ground. Increased sensitiveness of the pododerm is detected by compression of the hoof with the pincers (hoof-testers), or with greater certainty by lightly tapping the hoof. The increased warmth of a part or of the entire hoof is detected by feeling with the hand. Intense pain and greatly increased warmth, with a moderate, diffuse swelling of the soft parts between the hoof and fetlock-joint, indicate suppuration within the hoof.
The examination of horses lame in the feet must always be cautious and searching, and should begin with the moving and judging of the horse as already described on page 90. The faults detected in the hoof or in the shoeing, the pain and increased warmth of the hoof, will not leave us in doubt as to whether the animal is lame in the hoof or not. However, should there be a doubt, we must carefully examine all the joints and tendons of the foot and, if necessary, of the limb above, and observe the animal’s manner of travelling at a walk and at a trot, on soft and on hard ground, in a straight line and in a circle.
The removal of the shoe should be performed with greatest caution. Under certain conditions the second shoe should not be removed until the first has been replaced. The same caution must be observed in paring the hoof, which is to be regarded as a part of the examination of the hoof. The paring of a hoof for this purpose often differs somewhat from the preparation of a sound hoof for the shoe, and while it is necessary because it frequently furnishes the first trustworthy indication of the trouble, it must be done with circumspection and intelligence.
The causes of diseases of the hoof are very numerous, for many external influences act injuriously upon the hoof. In addition to too great dryness, want of care (neglected shoeing), and premature, unreasonable, cruel use of the horse, should be mentioned particularly injudicious dressing of the hoof and direct and indirect faults in the shoeing. The pododerm, shut in between the hard os pedis and the stiff, unyielding horn capsule, is frequently exposed to bruising and other injuries, from which arise most of the defects of the hoof itself. All these things lead, under certain conditions, to lameness.
Fig. 185.
Bar-shoe for right foot.
Treatment.—First of all, the discovered causes should be removed, or, if this is not possible, as is frequently the case, they should be ameliorated. Very often the lameness may be removed by proper shoeing, a change in the animal’s work, and better care of the hoof. When there is intense inflammation within the foot, the shoe should be removed for a few days. When the inflammation is moderate and confined to a small area, it is usually sufficient to alter the shoeing by regulating unnatural relations of height in the different parts of the wall, and by removing all superfluous horn from the wall and sole (to a less degree from the frog), partly for the purpose of rendering the horn capsule more yielding, and partly to make the poultices which are used more effective. The shoe is then to be so applied that the diseased region will be relieved of the body-weight, and will remain free from all pressure from the shoe. This can be done partly by making the underlying branch of the shoe somewhat wider and longer than the other, and partly by cutting down the bearing-edge of the wall where this is possible without weakening it too much, otherwise by concaving or beating down the upper surface of the shoe. By reason of the fact that the posterior half of the hoof is the seat of most diseases of the hoof, it is to be recommended that the nail-holes in shoes used in these diseases be placed as far as possible in the anterior half of the shoe, and in some special cases distributed evenly around the toe. Among shoes suitable for diseased hoofs the bar-shoe ([Fig. 185]) holds the first place, because it renders superfluous many other shoes specially designed for various diseases of the hoof. It is made like an ordinary flat shoe, except that it requires a somewhat longer piece of iron; the ends of the branches are bent inward over a dull corner of the anvil, bevelled, laid one over the other, and welded together to form the bar. The width and thickness of the bar should be the same as of the rest of the shoe, and its frog-surface should be slightly concave.
The bar-shoe is valuable, because it protects from pressure diseased sections of the wall which have been laid free, allows part of the body-weight to be borne by the frog, and restores normal activity to the disturbed physiological movements of the foot. By using it we can either gain a more extensive bearing-surface for the hoof, or can make it easier for the surface that bears the weight to do the work. If on account of weakness of the bearing-surface of the hoof, or from any other cause, we wish to distribute the body-weight over the entire plantar surface of the foot with the exception of the painful region, we add a leather sole to the bar-shoe.
In this case it is necessary to place holes in the ends of the branches of the shoe, so that we may rivet the leather firmly to the shoe with small nails. The shoe should be made somewhat wider than the hoof, and the clips somewhat higher than usual. After fitting the shoe the grooves for the clips are cut in the leather, the latter is riveted to the shoe, and all leather projecting beyond the outer edge of the shoe is trimmed away. The lacunæ of the frog and other concavities of the sole are then thickly smeared with wood-tar and afterwards filled up with oakum to such a degree that the packing will bear some of the body-weight when the shoe and leather sole are in position. This packing is of great importance, because it prevents the filtering in from behind of sand and slime, preserves the toughness and pliability of the horn, breaks shock, and produces a gradual expansion of the posterior half of the hoof. Before nailing the shoe to the foot the leather sole should be soaked in water.
Classification of Diseases of the Hoof.
INFLAMMATIONS OF THE PODODERM.
1, Nailing (pricking and close-nailing); 2, street-nail; 3, calk-wounds; 4, corns (bruised sole); 5, bruised heels; 6, laminitis (founder); 7, keraphyllocele (tumor of horny leaves).
DEFECTS OF THE HORN CAPSULE
AND LATERAL CARTILAGES.
(a) Changes of form: 1, flat hoof and full hoof (dropped sole); 2, upright hoof (stumpy or stubby hoof); 3, contracted hoof; 4, wry hoof; 5, crooked hoof; 6, ossification of the lateral cartilage (side-bone).
(b) Disturbances of continuity of the horn capsule: 1, cracks; 2, clefts; 3, loose wall; 4, hollow wall; 5, thrush.
CHAPTER VIII.
INFLAMMATIONS OF THE PODODERM
(PODODERMATITIS).
1. Nailing.
Wounds of the velvety tissue of the sole or of the podophyllous tissue of the wall, caused by nails which have been driven into the hoof for the purpose of fastening the shoe, are usually termed “nailing.”
We distinguish direct and indirect nailing; the former is noticed immediately, the latter later.
In direct nailing the nail passes directly into the pododerm (velvety tissue of the sole, podophyllous tissue); the wound produced may vary from a simple puncture of the pododerm to chipping of the border of the os pedis, and is always accompanied by bleeding, even though it may not always be noticed.
In indirect nailing the nail does not pass entirely through the horn capsule, but very close to the sensitive tissues, and crowds the soft horn inward against them. This inward bulging presses upon the pododerm and causes inflammation and lameness, which may not manifest themselves for several days.
Symptoms.—The first symptom of direct nailing is instant pain indicated by flinching or a jerking of the limb, showing that the nail has taken a wrong course, and then a more or less profuse hemorrhage. Usually the blood flows from the nail-hole, or the nail when withdrawn may merely show a bloodstain at its point; however, internal bleeding may occur without any external manifestations. The symptoms of indirect nailing are entirely different. In this case pain does not arise immediately, but later, sometimes as soon as the horse attempts to bear his weight upon the shod foot. In the latter case, on holding up the opposite foot the animal sways backward and throws his weight upon the holder, or becomes restless. As a rule, the consequences of indirect nailing are first manifested after two or three days, infrequently from the eighth to the fourteenth day, as inflammation within the hoof and lameness, at which time a careful examination will usually reveal increased warmth of the hoof, pain upon pressure with the hoof-testers and on tapping the hoof lightly, some swelling of the entire foot, increased pulsation of the digital arteries, and unwillingness of the animal to place all or perhaps any of its weight upon the foot.
Suspicion of nailing should be entertained if the shoeing be recent, the hoof appear too small in relation to the body-weight, the walls have been thinned by rasping or have been broken away, or if the nails have been driven too high or very irregularly.
Causes.—The most common causes are mistakes in shoeing. In the majority of cases the cause is a disregard of the rule that the nails should penetrate the white line ([see pages 118], [119] and [130], heavy type). 1, using badly-punched shoes; 2, excessive paring and shortening of the hoof; 3, weakening of the lower border of the wall by excessive rasping away of the outside ([Fig. 187, c]); 4, mistakes in fitting the shoe, especially applying shoes that are too narrow, letting the toe-clips too deep into the horn, by which the nail-holes near the toe, instead of falling upon the white line, are carried back upon the edge of the sole, or using shoes in which the nail-holes are too wide or improperly directed; 5, using nails that are split, incomplete, badly formed and bevelled, and too large; 6, starting nails too deep or with the bevel on the outside, or drawing them too tight. As occasional causes may be mentioned: 7, old nail-stubs in the horn; 8, walls that are very thin or broken away; 9, a soft, crumbling wall, which alters the sound and feeling of the nail as it is driven, and makes it difficult to judge of its course; 10, restlessness of the animal while being shod.
Examination.—Press with the hoof-testers upon the sole and clinches; tap lightly upon the clinches. If these acts cause pain, there can be little doubt that the nail is responsible for the damage. Remove the shoe by drawing each nail separately and carefully. Examine the nails with reference to their direction and size, as well as to staining with blood, blood-serum, or pus. Immediately after removing the shoe, look for the point of entrance of each nail into the hoof, and if a nail-hole be found upon the edge of the sole ([Fig. 187, b]) instead of in the white line, it is highly probable that the nail which passed in at that place pressed upon the sensitive tissues of the foot. Every nail-hole should then be searched by passing a clean new nail into it and pressing its point towards the soft tissues at various depths; any indication of pain caused by this act is pretty sure proof of nailing. It stands to reason that the character of the nail-holes in the shoe should be closely examined.
Fig. 186.
Cross-section of a shod hoof,
the hoof-skin or pododerm being
in red: a, indirect nailing
where backsetting has been
overdone and has bent the nail;
b, nail properly placed
and of correct shape.
Fig. 187.
Front hoof deficient in horn:
a, right position of the
nail-holes in the white line;
b, faulty position inside
of the white line; c, wall
weakened by excessive rasping.
Treatment.—When the foot has sustained an ordinary simple prick with a nail, the latter should be left out and the hole well filled with wax. As a rule, no serious results follow. In severe direct nailing the entire shoeing should be most carefully examined, and only after everything is found to be right, and the shoe fits in such a manner that the nails can only penetrate the wall from the white line, can it be regarded as correct. The offending nail-hole is then to be closed with wax. According to the intensity of the wound we may expect a more or less pronounced inflammation of the pododerm, and this is to be combated by resting the animal and cooling the foot.
If the wound is clean and recent, enlarging the opening in the horn by cutting and boring can have no reasonable object; the wound by such an act will not be made smaller, but larger.
Frequently, however, the wound is not observed or suspected until the pain has become very intense (indirect nailing, nail-pressure); in such cases the offending nail when withdrawn is apt to be covered with pus or a dark, thin, ill-smelling liquid. In such a case the liquid, whatever its nature may be, must be given free escape. In order to accomplish this it is entirely sufficient to cut away a section of the wall from the nail-hole outward, not greater than the width of the little finger, and then to assist in the discharge of the pus by placing the foot in a warm bath; it is entirely wrong, in fact, reprehensible, to remove all horn of the wall and sole which has been loosened from the soft parts by the suppurative process. After the escape of the inflammatory fluids, the wall and sole will form the best-fitting and most suitable protective dressing for the diseased region until it has secreted new horn. If, after removal of the nail and pus, the pain does not diminish, warm disinfecting baths of one to two parts of creolin, or the same amount of lysol, to one hundred parts of water at a temperature of about 90° F. will be of especial benefit; they will not only soften the horn, but by their moisture and warmth will directly diminish the pain and have a healing influence upon the suppurating surfaces. The warm baths must actually be warm and be kept warm. Antiseptic solutions at room temperature are much less efficient.
If the pain has not been very pronounced, or if it has been greatly alleviated by two or three warm baths, then, as a rule, it is sufficient to put a few drops of creolin upon the inflamed surface, and to close the opening with oakum (carbolized oakum or carbolized cotton is better).
The horse which has been nailed will be again perfectly serviceable after a few days if shod with a shoe which does not press upon the inflamed region. The shoe does not press when it rests only upon the bearing-edge of the wall, when the white line and the edge of the sole are entirely free of the shoe, and no nails are driven in the immediate vicinity of the wound.
Even though, as we have seen, nailing in the great majority of cases is not particularly serious to the horse and owner, yet we should never forget that tetanus (lockjaw), a disease which is nearly always fatal to horses, may follow. Nailing, however insignificant it may seem, may under conditions lead to the death of the horse.
2. Street-Nail.
The condition caused by accidental injury of the sensitive structures covered by the horny sole, such as the velvety tissue of the sole and frog, plantar cushion, perforans tendon, navicular bone, os pedis, or the pedal articulation, by sharp objects, especially nails, is called “penetrating street-nail,” or simply “street-nail.” The resistance of the ground to the weight of the body drives these penetrating objects through the sole or frog into the foot.
Hind hoofs are more often affected than fore-hoofs. A favorite point of entrance is the lateral lacuna of the frog. Street-nail is favored by excessive thinning of the sole and frog.
Symptoms.—The symptoms are, as a rule, sudden pain followed by lameness. The first assistance is usually sought in the shoeing shop. If the cause of lameness be found to be a penetrating nail, piece of glass, or other pointed foreign body, it must be carefully drawn out, in doing which we should remove the entire object, not allowing pieces to break off and remain in the wound. Since it is always important to know in what direction and how deep the foreign body has penetrated, in order to be able to estimate the gravity of the wound, it is advisable in all cases to preserve the penetrating body, that it may be shown to the veterinarian, in case his services are required.
Fig. 188.
Shod hind foot, with splint dressing.
In slight injuries to the velvety tissue of the sole or frog, accompanied with moderate pain, it is of no benefit to enlarge the opening, though the horn of the sole or frog should be thinned for the space of an inch or more around the wound, followed by cooling applications. Deep, penetrating wounds accompanied with intense pain require the attention of a veterinarian.
Often some form of dressing is necessary, and this is usually held in place by a special shoe. For slight injuries, such splint-dressings as are shown in [Figs. 188] and [189] are sufficient. Whether such a dressing be applied to the front or hind feet, the shoe should be well concaved upon the hoof-surface. The dressing is held in place by thin splints of tough wood, which are firmly wedged between the shoe and hoof.
Fig. 189.
A practical “splint shoe” for hospital use.
In those rare cases in which it is necessary to maintain continuous pressure upon the seat of the wound, and to protect the entire plantar surface of the hoof, a covered shoe ([Figs. 190] and [191]) is recommended. This shoe is provided with a sheet-iron cover, having at the toe a spur which fits into a corresponding hole in the toe of the shoe, and fastened at the heels by means of screw heel-calks.
3. Calk-Wounds of the Coronet.
All tread-wounds of the coronet, caused by the calks of the opposite shoe, by the shoes of other horses, or by forging, are known as calk wounds, or simply as “calking.” The injury itself is either a bruise or a bruised wound, followed by inflammation of the coronary cushion and an interruption in the formation of horn at that point. It occurs most often in winter from sharp calks, especially on the hind feet. The common seat of the injury is the coronet of the toe and inner side of the foot.
Fig. 190.
Fig. 191.
Shoe with cover-plate for street-nail treatment; suitable where pressure-dressing is desired: a, hole in the bottom of the toe-calk for reception of spur, b, of cover-plate; c, holes for reception of screw-calks, d, which fasten the cover-plate to the shoe.
The inflammation terminates either in resolution—that is, passes gradually away, leaving the tissues apparently normal—or in suppuration. The perioplic horn-band, which is usually loosened from the perioplic band by the injury, does not again unite. For this reason, and because of the interruption in the formation of horn at the seat of injury, there results a transverse depression or cleft in the wall.
The shoeing has to deal only with the lameness that may be present as a result of the calking. The section of the wall containing the lesion should be shortened, so that it will not press upon the shoe. Serious calk-wounds, as a rule, require treatment by a veterinarian.
4. Corns (Bruised Sole).
The expression “corns” is applied to nearly all bruises of the pododerm of the posterior half of the foot, with the exception of the frog, which are apparent to the eye as yellowish, reddish, or bluish-red discolorations of the horn of the sole and white line.
The surface of the pododerm (fleshy leaves and villi) is chiefly involved, and almost without exception there is rupture of small blood-vessels and an outpouring of blood between the pododerm and the horn. The blood penetrates the horn-tubes and causes the above-mentioned staining. By subsequent growth of horn these stained patches are carried downward, and are finally uncovered and brought to sight in paring the hoof.
The seat of corns is either on the fleshy leaves of the quarters, or on the velvety tissue of the sole in the angle between the wall and the bar, or on the fleshy leaves of the bars. Thus we distinguish corns of the wall, sole, and bars.
Corns affect chiefly the front hoofs, and more often the inner half than the outer. Unshod feet are seldom affected.
According to the intensity of the lesions we distinguish:
1. Dry Corns.—The red-stained horn is dry, and there is seldom lameness.
2. Suppurating Corns.—They are the result of intense bruising followed by inflammation. The pus is either thin and dark grayish in color, denoting a superficial inflammation of the pododerm, or yellowish and thick, denoting a deep inflammation of the pododerm. In the latter case a veterinarian should be called. Lameness is usually pronounced.
3. Chronic Corns.—In this case there is vivid discoloration of horn in all possible hues. The horn is either soft, moist, and lardy, or crumbling, cracked, and at times bloody. The inner surface of the horn capsule has lost its normal character, and is covered with horny swellings or nodules ([Fig. 192, a]). Sometimes the wing of the os pedis on that side has become morbidly enlarged and loosened. A short, cautious gait alternates with well-marked lameness; the latter appears whenever the shoe presses too firmly on the corn, or when the hoof becomes too dry.
Fig. 192.
Inner aspect of a quarter of a hoof, showing changes in the horn-leaves due to chronic corns: a, horny tumor resulting from the disease.
The causes, aside from the form and quality of the hoofs and the position of the limbs, lie in injudicious dressing of the hoof and in faulty shoes. Too much trimming of wide and flat hoofs, excessive weakening of the quarters, sole, bars, and frog of all other hoofs, while the toe is usually left too long, are the usual causes. Shortening one quarter too much in relation to the other, so that the foot is unbalanced and the lower side overloaded, is a frequent cause. Hollowing the sole and bars excessively and unnecessary thinning of the branches of the sole in the search for corns are also causes.
Among faulty shoes we may mention those not level on the hoof-surface, trough-shaped, too short in the branches, shoes which do not completely cover the bearing-surface of the hoof, or whose bearing-surface at the ends of the branches is directed downward and inward so that the quarters are squeezed together when the weight is put on the foot. Insufficient concaving of the shoe is often an exciting cause of corns in flat feet and in those with dropped soles. A well-formed shoe which does not rest firmly upon the hoof, or which has been shifted as a result of careless nailing, may as readily cause bruising of the quarters as neglected shoeing. The latter causes, as a rule, corns of the sole. It is very rarely that corns are caused by stones fastened between the frog and branches of the shoe or in unshod hoofs by pebbles becoming wedged in the white line.
Dryness is particularly injurious to the hoofs, and is in the highest degree favorable to the production of corns. It renders the hoof stiff and inelastic, and first manifests itself by a short, cautious (sore) gait when the horse is first put to work.
Treatment.—First, removal of the causes, by restoring the proper form to the hoof through shortening a toe which is too long (especially apt to be the case in acute-angled hoofs), cutting down quarters which are too high, and carefully removing all dead horn from the branches of the sole, especially in acute-angled hoofs.
Deeply digging out a small area of blood-stained horn is injurious. It is much better to thin the horn of the entire branch of the sole uniformly, in doing which we should avoid wounding the velvety tissue of the sole or drawing blood.
The proper shoe is the bar-shoe, except when both cartilages are ossified. The pressure should not be taken from the quarters unless they are sore.
When there is a suppurating corn, the shoe should be left off several days. A chronic corn should be protected continuously from pressure by the shoe. This is accomplished by using a bar-shoe with leather sole. A three-quarter shoe is not sufficient to properly protect a hoof affected with a chronic corn, if the animal must perform exacting labor on hard roads.
The care of the hoof consists in keeping it cool, moderately moist, and pliant.
5. Inflammation of the Heels.
Inflammation of the bulbs of the plantar cushion (heels) is usually caused by such external influences as bruising. It occurs in both shod and unshod feet. The symptoms are: increased warmth, pain and swelling, sometimes infiltration of the tissues with blood, accompanied by a short, cautious gait, or, if only one foot is affected, by well-marked lameness.
The most frequent causes are: going barefoot upon hard (frozen), uneven ground; shoeing hoofs having low heels with flat shoes that are too short; sometimes too much frog pressure by the bar of a bar-shoe; forging and grabbing.
The treatment first indicated is a cooling application in the form of an ice-poultice, or a soaking in cold water. Later, astringent (drying) applications are of benefit, especially if the perioplic horn-ring has partially loosened from the bulbs of the heels; for example, a weak solution in water of sulphate of copper (1 to 20), followed by the application of a shoe with heel-calks, which is quite long in the branches and which must not press upon the wall of the quarters.
6. Laminitis (Founder).
By this name we designate a peculiar inflammation of the pododerm at the toe. It arises suddenly in well-nourished and apparently healthy horses, following excessive work or long-continued rest in the stable, and frequently leads to a decided change of form of the hoof.
The disease is always accompanied with intense pain. It most often affects both front feet, more rarely all four feet, or only one foot. In the first case the two front feet are planted far in advance of the body, and the hind feet well forward under the belly. When all four feet are affected, travelling is exceedingly difficult, often impossible; in this case there is nearly always a high fever over the entire body.
The seat of the disease is in the fleshy leaves about the toe, more rarely upon the side walls and quarters. Depending upon the intensity of the inflammation, the fleshy leaves are more or less loosened from the horny leaves, as a result of which there is a change of position of the os pedis, with a simultaneous sinking of the coronet at the toe. This produces a change of form of the hoof. The quarters become higher. Rings form upon the wall, and their course is quite characteristic of the disease. At the toe these rings are quite close to one another, but as they pass back towards the quarters they gradually separate from one another and recede from the coronary band ([Figs. 193], [194], and [195]).
Fig. 193.
Vertical longitudinal section of a foot altered by chronic laminitis: a, hollow wall at toe thrust forward; b, leafy layer much thickened and crumbling (“seedy-toe”); c, dotted line showing limit to which the toe may be rasped away in shoeing; d, dropped sole; e, atrophy of lower sharp edge of os pedis; g, dotted line indicating the height of the perioplic band; h, foot axis.
The wall at the toe is sunken just under the coronet; its lower part, on the contrary, is thrust forward. Later, the white line becomes pathologically widened. The horn of the white line is dry, crumbling, and easily broken down, so that a break in continuity (crack) is apt to occur between the wall and sole, and lead to the formation of a hollow wall (“seedy-toe”). Where the inflammation is moderate and is not repeated, healing usually takes place and the horn grows down regularly and in normal direction from the coronet. However, a rather brittle condition of the horn remains permanently. If, on the contrary, the inflammation was very severe or repeated several times, the horny sole becomes flat just in front of the point of the frog as a result of the sinking of the os pedis, or it may even drop below the level of the wall (full hoof, dropped sole). Indeed, it even happens at times that the toe of the os pedis perforates the horny sole just in front of the point of the frog. The wall at the toe, which was previously but little altered in form, is now thrust prominently forward.
Fig. 194.
Foundered foot
(chronic laminitis),
before dressing.
Fig. 195.
Foundered foot, dressed and shod.
The dotted lines indicate its form
before being dressed,—i.e.,
as shown in Fig. 194.
The inflammation of the pododerm may under certain conditions and by skilful veterinary treatment be removed, so that the characteristic changes of form and quality of the hoof will not occur. But if this is not accomplished, as is often the case, the disease will be obstinate, and permanent morbid changes of the horn capsule take place.
Fig. 196.
A hoof altered by chronic laminitis; shod with an open flat shoe: a, wall at the toe does not bear on the shoe; b, clip at the end of the branch to oppose the tendency of the shoe to slip forward when half worn out.
A horse in such a condition can be used, but the gait will be short and stiff. The hoofs are shuffled forward and set heels first to the ground, a manner of travelling that rapidly wears away the branches of the shoe.
In dressing a foundered hoof the outer circumference of the sole is the guide. The thick projecting wall at the toe may be removed with the rasp without injuring the foot. The sole should be spared, but the quarters should be lowered to improve the setting of the foot to the ground.
The choice of the shoe will depend upon the shape and nature of the sole. If this is still concave, an ordinary shoe may be used. If, however, the sole is flat or dropped, it must be protected by an open shoe with a broad web, or with a bar-shoe ([Fig. 197]), which is of especial value when the bearing-edge of the wall is weak or broken away.
Fig. 197.
A well-covered (wide-webbed) bar-shoe,
with two lateral toe-clips and an
end-clip, for a foundered foot.
Fig. 198.
An open shoe for a foundered
foot with a dropped sole.
As long as there is pain on pressure about the toe there should be no toe-clip, but two side-clips. The wall between these clips should be lowered a tenth to an eighth of an inch to prevent pressure of the shoe upon the sensitive tissues of the toe ([Fig. 195]). The nails should be as small as possible and placed well back towards the quarters. No nail should be driven in the wall at the toe when there is separation of sole and wall at the toe (hollow wall, seedy-toe).
The shoes of horses affected with founder often work forward as a result of the animals travelling upon their heels. To prevent this evil, clips may be raised at the ends of the branches of an open shoe, or one clip in the middle of the bar, in case a bar-shoe is used ([Fig. 197]).
7. Keraphyllocele
(Horn Tumor).
A keraphyllocele is a more or less sharply bounded horn tumor projecting from the inner surface of the wall.
Fig. 199.
A section of wall at the toe showing a Keraphyllocele (horn-leaf tumor): a, coronary border; b, plantar border; c, body of tumor; d, base of tumor presenting funnel-shaped opening discharging pus.
Its occurrence is rare. Its favorite seat is at the toe. It rarely causes lameness. It can only be diagnosed with certainty when it extends downward to the lower border of the wall. In this case there may be seen a half-moon-shaped thickening of the white line which rounds inward upon the edge of the sole, and is of a waxen color. Frequently the horn at this place crumbles away, leaving a more or less dark-colored cavity from which there sometimes escapes a small quantity of dark-grayish pus.
Causes.—Chronic inflammation of the podophyllous tissue, resulting from compression or bruising. Keraphyllocele frequently follows a complete toe-crack of long duration, or a deep calk-wound at the coronet.
Prognosis.—Unfavorable, whether there is lameness or not. If there is no lameness it is very apt to arise later, and if lameness is already present it can only be removed by an operation, which should be performed by a veterinarian. A return of the lameness following hard work at a trot upon hard roads is always to be feared.
Shoeing.—An ordinary shoe well concaved underneath the inflamed region, which should be relieved of all pressure.[5]
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.
Fig. 200.
Cross-section of a shod flat foot: a, sufficiently high bearing-edge of wall, and a horizontal bearing-surface on the shoe; b, insufficient height of bearing-edge of wall, and therefore a corresponding downward and inward inclination of the bearing-surface of the shoe.
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 he 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 he 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.
Fig. 201.
Upright or stumpy hoof,
shod with a “tip.”
Fig. 202.
Beaked shoe for stilt-foot.
Causes.—1. The upright hoof is peculiar to the “standing under” position ([Fig. 53], page 66) and to the so-called bear-foot ([Fig. 70], page 72).
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]).
Fig. 203.
Fig. 204.
Shoe for stumpy hoofs, viewed from ground-surface,
hoof-surface, and in profile.
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]).
Fig. 205.
A fore-hoof with bilateral contraction of the quarters: a, spur of horn prolonged from the buttress, which compresses the frog; b, narrow median lacuna of the frog.
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.
Fig. 206.
A, Defay’s shoe for
expanding the quarters
of a hoof; a, clip
apposed to the buttress;
b, slot sawed at the
toe to weaken the shoe;
B, screw for expanding
the Defay’s shoe.
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 lacunæ. If the frog is small and narrow, and the lateral lacunæ 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 be 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 be 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 on pages 98 to 103, 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]).
Fig. 207.
The Chadwick spring for expanding
contracted quarters: a, apex
of spring; b, ferrule to
stiffen the spring; c,
point which is buried in a
buttress of the hoof.
Fig. 208.
A fore-hoof showing a Chadwick
spring in proper position:
a, Chadwick spring;
b, ferrule to stiffen
spring as desired; c,
uncompressed spring before it
has been engaged against the
buttresses; d, buttresses
in which points of spring
are buried.
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 bearing-surface 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.
Fig. 209.
Wide fore-hoof with “coronary contraction”: (a) broad shallow groove in each quarter, and disappearing toward the toe.
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.
Fig. 210.
A fore-hoof with a contracted sole, properly shod: a, toe convex in profile; b, shoe fitted full all around, and “bearing-surface” inclining outward; c, outer border bevelled base-wide.
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.
Fig. 211.
A wry right front foot of the base-wide class, viewed from behind. The bar-shoe is fitted full along the contracted inner quarter, and snug on the outside. The inner branch of the frog rests upon the bar of the shoe; the outer branch is free. The inner quarter from the last nail back to the frog is free of the shoe.
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.
Fig. 212.
A crooked right fore-hoof of the base-wide position: a, convex wall, too high; b, concave wall, too low; c d shows how much of the outer wall must be removed with the hoof-knife; f, superfluous horn to be removed gradually with the rasp; c e and g h indicate the position of the shoe with relation to the hoof.
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.
Fig. 213.
A left fore os pedis viewed in profile, showing ossification of the external lateral cartilage: a, dotted line shows normal line of union of cartilage with wing of os pedis; b, ossified portion (“side bone”). The unossified cartilage has been removed by maceration.
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.
Fig. 214.
Right fore-hoof whose form has
changed as a result of ossification
of the external lateral cartilage.
Fig. 215.
Shoe with broad outer branch, for
the hoof shown in the preceding cut.
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.
Fig. 216.
Hoof exhibiting a coronary crack, a plantar or low crack, and a complete deep crack, the latter with a nail ready to be clinched.
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.
Fig. 217.
Toe-crack immobilized by lateral toe-clips: a, bearing-surface left free from pressure; b, heads of the rivets (nails) driven through holes previously drilled.
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 rubber pad, 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 toe-clips ([Fig. 217]) are drawn up, and the wall between these clips is cut down from a twelfth to an eighth of an inch.
Fig. 218.
Spiral drill for boring the hole into which a round wire nail is driven to fasten a toe-crack: (a) three sided point of drill (similar to the point of a stilet of a cæcal trocar).
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 tothe 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]).
Fig. 219.
A, Vachette burning iron for making the two slots to receive the ends of the hook; b, shoulder; B, Vachette hook; C, pincers for forcing the hook into the wall.
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 quarter-crack 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.
Fig. 220.
Hoof with coronary quarter-crack, shod with a bar-shoe. The part of the quarter relieved of pressure a, is indicated by the dotted lines; b, iron plate secured by small wood screws ⁴/₁₆-⁵/₁₆ of an inch in length.
Fig. 221.
Hoof with complete quarter-crack, shod with a bar-shoe: a, area thinned almost to the pododerm; b, ¹/₁₆ inch metal plate secured by screw ⁵/₁₆ of an inch long; c, quarter relieved of pressure from bottom of crack to a perpendicular dropped from top of crack.
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 stretching 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 ([see page 173]). 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.
Fig. 222.
Hoof with clefts of the toe and side wall.
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]).
Fig. 223.
An imaginary transverse vertical section of a hoof
showing (a) loose wall and (b) hollow wall.
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 (see growth of the hoof, [page 82]).
5. Thrush of the Frog.
When the horny frog is ragged and fissured, and an ill-smelling, dark-colored liquid collects in the lacunæ 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]).
Fig. 224.
Hoof with irregular superficial rings
resulting from thrush of the frog.
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 ([see page 100]), 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, AND 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.
Fig. 225.
A mule’s hoof.
(Plantar surface).
Fig. 226.
A shod ox-claw.
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.
Fig. 227.
Pair of machine-made ox shoes, viewed from the ground-surface and in profile; a, toe-calk; b, heel-calks.
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.
Fig. 228.
Hind foot raised by means of a round pole.
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.
Fig. 229.
Gutenäcker’s stocks for oxen: a, front corner-posts; b, rear corner-posts; c, d, connecting bars; e, head-post; f, bar for holding belly girth; g, hooks for girth; h, neck-yoke; i, pulley-wheel; k, windlass with ratchet and click; m, slot for neck-yoke and breast-bar; n, slot for movable side-bars; o, p, side-bars; r, hook for fetlock strap; s, iron bracket; t, iron ring for rear cross pole; u, hooks for breeching.
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 side-bar, 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.