Fast work on hard roads, jumping, and blows on the coronet, together with calk wounds of the feet, are accidental causes of quarter cracks in particular. Toe cracks are more likely to be caused by heavy pulling on slippery roads and pavements or on steep hills.
Symptoms.—The fissure in the horn is ofttimes the only evidence of the disease; even this may be accidentally or purposely hidden from casual view by mud, ointments, tar, wax, putty, gutta-percha, or by the long hairs of the coronet.
Sand cracks sometimes commence on the internal face of the wall, involving its whole thickness excepting a thin layer on the outer surface. In these cases the existence of the injury may be suspected from a slight depression, which begins near the coronary band and follows the direction of the horny fibers; but the trouble can only be positively diagnosed by paring away the outside layers of horn until the fissure is exposed. In toe cracks the walls of the fissure are in close apposition when the foot receives the weight of the body, but when the foot is raised from the ground the fissure opens. In quarter crack the opposition is true; the fissure closes when the weight is removed from the foot. As a rule, sand cracks begin at the coronary band, and as they become older they not only extend downward, but they also grow deeper. In old cases, particularly in toe cracks, the horn on the borders of the fissure loses its vitality and scales off, sometimes through the greater part of its thickness, leaving behind a rough and irregular channel extending from the coronet to the end of the toe.
In many cases of quarter crack, and in some cases of toe crack as well, if the edges remain close together, with but little motion, the fissure is dry; but in other cases a thin, offensive discharge issues from the crack and the ulcerated soft tissues, or a funguslike growth protrudes from the narrow opening.
When the cracks are deep and the motion of their edges considerable, so that the soft tissues are bruised and pinched with every movement, a constant inflammation of the parts is maintained and the lameness is severe.
Ordinarily the lameness of sand crack is slight when the patient walks, but it is greatly aggravated when he is made to trot, and the harder the road the worse he limps. Furthermore, the lameness is greater going downhill than up, for the reason that these conditions are favorable to an increased motion in the edges of the fissure. Lastly, more or less hemorrhage accompanies the inception of a sand crack when the whole thickness of the wall is involved. Subsequent hemorrhages may also take place from fast work, jumping, or a misstep.
Treatment.—So far as preventive measures are concerned, but little can be done. The suppleness of the horn is to be maintained by the use of ointments, damp floor, bedding, etc. The shoe is to be proportioned to the weight and work of the animal; the nails holding it in place are to be of proper size and not driven too near the heels; sufficient calks and toe pieces must be added to the shoes of horses working on slippery roads; also, the evils of jumping, fast driving, etc., are to be avoided.
When a fissure has made its appearance, means are to be adopted which will prevent it from growing longer or deeper; this can only be done by arresting all motion in the edges. The best and simplest artificial appliance for holding the borders of a toe crack together is the Vachette clasp. These clasps and the instruments necessary for their application can be had of any prominent maker of veterinary instruments. (Pl. XXXVI.) These instruments comprise a cautery iron, with which two notches are burned in the wall, one on each side of the crack, and forceps with which the clasps are closed into place in the bottom of the notches and the edges of the fissure brought close together. The clasps, being made of stiff steel wire, are strong enough to prevent all motion in the borders of the crack. Before these clasps are applied the fissure should be thoroughly cleansed and dried, and if the injury is of recent origin the crack may be filled with a putty made of 2 parts of gutta-percha and 1 part of gum ammoniac. The number of clasps to be used is to be determined by the length of the crack, the amount of motion to be arrested, etc. Generally the clasps are from one-half to three-quarters of an inch apart. The clasps answer equally as well in quarter crack if the wall is sufficiently thick and not too dry and brittle to withstand the strain.
In the absence of these instruments and clasps a hole may be drilled through the horn across the fissure and the crack closed with a thin nail made of tough iron, neatly clinched at both ends. A plate of steel or brass is sometimes fitted to the parts and fastened on with short screws; while this appliance may prevent much gaping of the fissure, it does not entirely arrest motion of the edges, for the reason that the plate and screw can not be rendered immobile.
If, for any reason, the measures above fail or can not be used, recourse must be had to an operation. The horn is softened by the use of warm baths and poultices, the patient cast, and the walls of the fissure entirely removed with the knife. The horn removed is in the shape of the letter V, with the base at the coronet. Care must be taken not to injure the coronary band and the laminæ. The wound is to be treated with mild stimulant dressings, such as compound cresol solution, a weak solution of carbolic acid, tincture of aloes, etc., oakum balls, and a roller bandage. After a few days the wound will be covered with a new, white horn, and only the oakum and bandages will be needed. As the new quarter grows out, the lameness disappears, and the patient may be shod with a bar shoe and returned to work.
In all cases of sand crack the growth of horn should be stimulated by cauterizing the coronary band or by the use of blisters. In simple quarter crack recovery will often take place if the coronet is blistered, the foot shod with a "tip," and the patient turned to pasture.
The shoe in toe crack should have a clip on each side of the fissure and should be thicker at the toe than at the heels. The foot should be lowered at the heels by paring, and spared at the toe, except directly under the fissure, where it is to be pared away until it sets free from the shoe.
When any of the complications referred to above arise, special measures must be resorted to. For the proper treatment of gangrene of the lateral cartilage and extensor tendon and caries of the coffin bone reference may be had to the articles on quittors. If the horny tumor, known as keraphyllocele, should develop, it is to be removed by the use of the knife. Since this tumor develops on the inside of the horny box and may involve other important organs of the foot in disease, its removal should only be undertaken by a skillful surgeon.
Navicular disease is an inflammation of the sesamoid sheath, induced by repeated bruising or laceration, and complicated in many cases by inflammation and caries of the navicular bone. In some instances the disease undoubtedly begins in the bone, and the sesamoid sheath becomes involved subsequently by an extension of the inflammatory process. (Plate XXXIV, fig. 5.)
The Thoroughbred horse is more commonly affected than any other, yet no class or breed of horses is entirely exempt. The mule, however, seems rarely, if ever, to suffer from it. For reasons which will appear when considering the causes of the disease, the hind feet are not liable to be affected. Usually but one fore foot suffers from the disease, but if both should be attacked the trouble has become chronic in the first before the second shows signs of the disease.
Causes.—To comprehend fully how navicular disease may be caused by conditions and usages common to nearly all animals, it is necessary to recall the peculiar anatomy of the parts involved in the process and the functions which they perform in locomotion.
It must be remembered that the fore legs largely support the weight of the body when the animal is at rest, and that the faster he moves the greater is the shock which the fore feet must receive as the body is thrown forward by the propelling force of the hind legs. This shock could not be withstood by the tissues of the fore feet and legs were it not that it is largely dissipated by the elastic muscles which bind the shoulder to the body, the ease with which the arm closes on the shoulder blade, and the spring of the fetlock joint. Even these means, however, are not sufficient within themselves to protect the foot from injury; so nature has further supplemented them by placing the coffin joint on the hind part of the coffin bone instead of directly on top of it, whereby a large part of the shock of locomotion is dispersed before it can reach the vertical column represented by the cannon, knee, and arm bones. A still further provision is made by placing a soft, elastic pad—the frog and plantar cushion—at the heels to receive the sesamoid expansion of the flexor tendon as it is forced downward by the pressure of the coronet bone against the navicular. Extraordinary as these means may appear for the destruction of shock, and ample as they are when the animal is at a slow pace or unweighted by rider or load, they fail to relieve the parts completely from concussion and excessive pressure whenever the opposite conditions are present. The result, then, is that the coronet bone forces the navicular hard against the flexor tendon, which, in turn, presses firmly against the navicular as the force of the contracting muscles lifts the tendon into place. It is self-evident, then, that the more rapid the pace and the greater the load, the greater must these contending forces be, and the greater the liability to injury. For the same reason horses with excessive knee action are more liable to suffer from this disease than others, concussion of the foot and intense pressure on the tendon being common among such horses.
Besides the above-mentioned exciting causes must be considered those which predispose to the disease. Most prominent among these is heredity. It may be claimed, however, that an inherited predisposition to navicular disease consists not so much in a special susceptibility of the tissues which are involved in the process as in a vice of conformation which, as is well known, is liable to be transmitted from parent to offspring. The faults of conformation most likely to be followed by the development of navicular disease are an insufficient plantar cushion, a small frog, high heels, excessive knee action, and contracted heels. Finally, the environments of domestication and use, such as dry stables, heavy pulling, bad shoeing, punctured wounds, etc., all have their influence in developing this disease.
Symptoms.—In the early stages of navicular disease the symptoms are generally very obscure. When the disease begins in inflammation of the navicular bone, the animal while at rest points the affected foot a time before any lameness is seen. While at work he apparently travels as well as ever, but when placed in the stable one foot is set out in front of the other, resting on the toe, with fetlock and knee flexed. After a time, if the case is closely watched, the animal takes a few lame steps while at work, but the lameness disappears as suddenly as it came, and the driver doubts whether the animal was really lame at all. Later the patient has a lame spell which may last during a greater part of the day, but the next morning it is gone; he leaves the stable all right, but goes lame again during the day. In times he has a severe attack of lameness, which may last for a week or more, when a remission takes place and it may be weeks or months before another attack supervenes. Finally, he becomes constantly lame, and the more he is used the greater the lameness.
In the lameness from navicular disease the affected leg always takes a short step, and the toe of the foot first strikes the ground; so the shoe is most worn at this point. If the patient is made to move backward, the foot is set down with exceeding great care, and the weight rests upon the affected leg but a moment. When exercised he often stumbles, and if the road is rough he may fall on his knees. If he is lame in both feet the gait is stilty, the shoulders seem stiff, and, if made to work, he sweats profusely from intense pain. Early in the development of the disease a careful examination will reveal some increased heat in the heels and frog, particularly after work; as the disease progresses this becomes more marked, until the whole foot is hot to the touch. At the same time there is an increased sensibility of the foot, for the patient flinches from the percussion of a hammer lightly applied to the frog and heels or from the pressure of the smith's pincers. The frog is generally shrunken, often of a pale-red color, and at times is affected with thrush. If the heels are pared away so that all the weight is received on the frog, or if the same result is attained by the application of a bar shoe, the animal is excessively lame. The muscles of the leg and shoulder shrink away and often tremble as the animal stands at rest. After months of lameness the foot is found to be shrunken in its diameter and apparently lengthened; the horn is dry and brittle and has lost its natural gloss, while circular ridges, developed most toward the heels, cover the upper part of the hoof. When both feet are affected the animal points first one foot then the other, and stands with the hind feet well forward beneath the body, so as to relieve the fore feet as much as possible from bearing weight. In old cases the wasting of the muscles and the knuckling at the fetlock become so great that the leg can not be straightened and locomotion can scarcely be performed. The disease generally makes a steady progress without inclining to recovery—the remission of symptoms in the earlier stages should not be interpreted as evidence that the process has terminated. The complications usually seen are ringbones, sidebones, thrush, contracted heels, quartercracks, and fractures of the navicular, coronet, and pastern bones.
Treatment.—But few cases of navicular disease recover. In the early stages the wall of the heels should be rasped away, as directed in the treatment for contracted heels, until the horn is quite thin; the coronet should be well blistered with Spanish-fly ointment, and the patient turned to grass in a damp field or meadow. After three or four weeks the blister should be repeated. This treatment is to be continued for two or three months. Plane shoes are to be put on when the patient is returned to work. In chronic cases the animal should be put to slow, easy work. To relieve the pain, neurotomy may be performed—an operation in which the sense of feeling is destroyed in the foot by cutting out pieces of the nerve at the fetlock. This operation in nowise cures the disease, and, since it may be attended with serious results, can be advised only in certain favorable cases, to be determined by the veterinarian.
A sidebone consists in a transformation of the lateral cartilages found on the wings of the coffin bone into bony matter by the deposition of lime salts. The disease is a common one, especially in heavy horses used for draft, in cavalry horses, cow ponies, and other saddle horses, and in runners and trotters.
Sidebones are peculiar to the fore feet, yet they occasionally develop in the hind feet, where they are of little importance since they cause no lameness. In many instances sidebones are of slow growth and, being unaccompanied with acute inflammation, they cause no lameness until such time as, by reason of their size, they interfere with the action of the joint. (Plate XXXIV, fig. 4.)
Causes.—Sidebones often grow in heavy horses without any apparent injury, and their development has been attributed to the over-expansion of the cartilages caused by the great weight of the animal. Blows and other injuries to the cartilages may set up an inflammatory process which ends in the formation of these bony growths. High-heeled shoes, high calks, and long feet are always classed among the conditions which may excite the growth of sidebones. They are often seen in connection with contracted heels, ringbones, navicular disease, punctured wounds of the foot, quarter cracks, and occasionally as a sequel to founder.
Symptoms.—In the earlier stages of the disease, if inflammation is present, the only evidence of the trouble to be detected is a little fever over the seat of the affected cartilage and a slight lameness. In the lameness of sidebones the toe of the foot first strikes the ground and the step is shorter than natural. The subject comes out of the stable stiff and sore, but the gait is more free after exercise.
Since the deposit of bony matter often begins in that part of the cartilage where it is attached to the coffin bone, the diseased process may exist for some time before the bony growth can be seen or felt. Later, however, the cartilage can be felt to have lost its elastic character, and by standing in front of the animal a prominence of the coronary region at the quarters can be seen. Occasionally these bones become so large as to bulge the hoof outward, and by pressing on the joint they so interfere with locomotion that the animal becomes entirely useless.
Treatment.—So soon as the disease can be diagnosed active treatment should be adopted. Cold-water bandages are to be used for a few days to relieve the fever and soreness.
The improvement consequent on the use of these simple measures often leads to the belief that the disease has recovered; but with a return to work the lameness, fever, etc., reappears. For this reason the use of blisters, or, better still, the firing iron, should follow on the discontinuance of the cold bandages.
But in many instances no treatment will arrest the growth of these bony tumors, and as a palliative measure neurotomy must be resorted to. Generally this operation will so relieve the pain of locomotion that the patient may be used for slow work; but in animals used for fast driving or for saddle purposes, the operation is practically useless. Some years ago at Fort Leavenworth I unnerved a number of cavalry horses that were suffering from sidebones, and the records show that in less than seven months all were more lame than ever. Since a predisposition to develop sidebones may be inherited, animals suffering from this disease should not be used for breeding purposes unless the trouble is known to have originated from an accident.
A ringbone is the growth of a bony tumor on the ankle. This tumor is, in fact, not the disease, but simply the result of an inflammatory action set up in the periosteum and bone tissue proper of the pastern bones. (Plate XXXIV, fig. 1.) (See also p. 313.)
Causes.—Injuries, such as blows, sprains, overwork in young, undeveloped animals, fast work on hard roads, jumping, etc., are among the principal exciting causes of ringbone. Horses most disposed to this disease are those with short, upright pasterns, for the reason that the shock of locomotion is but imperfectly dissipated in the fore legs of these animals. Improper shoeing, such as the use of high calks, a too great shortening of the toe and correspondingly high heels, predispose to this disease by increasing the concussion to the feet.
Symptoms.—The first symptom of an actively developed ringbone is the appearance of a lameness more or less acute. If the bony tumor forms on the side or upper parts of the large pastern, its growth is generally unattended with acute inflammatory action, and consequently produces no lameness or evident fever. These are called "false" ringbones. But when the tumors form on the whole circumference of the ankle, or simply in front under the extensor tendon, or behind under the flexor tendons, or if they involve the joints between the two pastern bones, or between the small pastern and the coffin bone, the lameness is always severe. These constitute the true ringbone. Besides lameness, the ankle of the affected limb presents more or less heat, and in many instances a rather firm, though limited, swelling of the deeper tissues over the seat of the inflammatory process. The lameness of ringbone is characteristic in that the heel is first placed on the ground when the disease is in a fore leg, and the ankle is kept as rigid as possible. In the hind leg, however, the toe strikes the ground first, when the ringbone is high on the ankle, just as in health, but the ankle is maintained in a rigid position. If the bony growth is under the front tendon of the hind leg, or if it involves the coffin joint, the heel is brought to the ground first. In the early stages of the disease it is not always easy to diagnose ringbone, but when the deposits have reached some size they can be felt and seen as well.
The importance of a ringbone depends on its seat and often on its size. If it interferes with the joints or with the tendons it may cause an incurable lameness, even though small. If it is on the sides of the large pastern, the lameness generally disappears as soon as the tumor has reached its growth and the inflammation subsides. Even when the pastern joint is involved, if complete anchylosis results, the patient may recover from the lameness with simply an imperfect action of the foot remaining, due to the stiff joint.
Treatment.—Before the bony growth has commenced the inflammatory process may be cut short by the use of cold baths and wet bandages, followed by one or more blisters. If the bony deposits have begun, the firing iron should always be used. Even when the tumors are large and the pastern joint involved, firing often hastens the process of anchylosis and should always be tried.
When the lower joint is involved, or if the tumor interferes with the action of the tendons, recovery is not to be expected. In many of these latter cases, however, the animal may be made serviceable by proper shoeing. If the patient walks with the toe on the ground, the foot should be shod with a high-heeled shoe and a short toe. On the other hand, if he walks on the heel, a thick-toed and thin-heeled shoe must be worn.
Since ringbone is considered to be one of the hereditary diseases, no animal suffering from this trouble should ever be used for breeding purposes.
Laminitis is a simple inflammation of the sensitive laminæ of the feet, characterized by the general phenomena attending inflammation of the skin and mucous membranes, producing no constitutional disturbances except those dependent upon the local disease, and having a strong tendency, in severe cases, to destructive disorganization of the tissues affected.
Causes.—The causes of laminitis are as wide and variable as in any of the local inflammations, and may be divided into two classes—the predisposing and the exciting.
Predisposing causes.—From personal observation I do not know that any particular construction of foot or any special breed of horses is predisposed to this disease, neither can I find anything to warrant the assumption that it is in any way hereditary; so that while we may easily cultivate a predisposition to the disease, it does not originate without an exciting cause. Like most other tissues, a predisposition to inflammation may be induced in the sensitive laminæ by any cause which lessens their power of withstanding the work imposed on them. It exists to an extent in those animals unaccustomed to work, particularly if they are plethoric, and in all that have been previous subjects of the disease, for the same rule holds good here that we find in so many diseases—i. e., that one attack impairs the functional activity of the affected tissues and renders them more easy of a subsequent inflammation. Unusual excitement by determining an excessive blood supply, bad shoeing, careless paring of the feet by removing the sole support, and high calkings without corresponding toe pieces must be included under this head.
Exciting causes.—The exciting causes of laminitis are many and varied. The most common are concussion, overexertion, exhaustion, rapid changes of temperature, ingestion of certain feeds, purgatives, and the oft-mentioned metastasis.
(1) Concussion produces this disease by local overstimulation. The excessive excitement is followed by an almost complete exhaustion of the functional activity of the laminated tissues, the exhaustion by congestion, and eventually by inflammation. But congestion here, as in all other tissues, is not necessarily followed by inflammation; for, although the principal symptoms belonging to true laminitis are present, the congestion may be relieved before the processes of inflammation are fully established. This is the condition in the many so-called cases of laminitis which recover in from 24 to 48 hours. They should be called congestion of the laminæ.
Laminitis from concussion is common in trotting horses that are raced when not in condition, especially if they carry the obnoxious toe weights, and in green horses put to work on city pavements to which they are unaccustomed. Concussion from long drives on dirt roads is at times productive of the same results, notably when the weather is extremely warm, or at least when the relative change of temperature is great. But the exhaustion of these circumstances must prove an exciting cause as well as the long-continued concussion. This combination of causes must also determine the disease at times in hunters, for the weight of the rider increases the demands made upon the function of these tissues, and their powers are the sooner exhausted.
(2) Overexertion, as heavy pulling or rapid work, even when there is no immoderate concussion, occasionally results in this disease. Here also exhaustion is a conjunctive cause, for overexertion can not be long continued without exhaustion.
(3) Exhaustion is nearly as prolific a source of laminitis as is concussion, for when the physical strength is impaired, even though temporarily, some part of the economy is rendered more vulnerable to disease than others. To this cause we must ascribe those cases which follow a hard day's work, in which at no time has there been overexertion or immoderate concussion.
The tendency to laminitis in horses on sea voyages results from the continual constrained position the animal maintains on account of the rocking motion of the vessel.
If one foot has been blistered, or if one limb is incapacitated from any cause, the opposite member, doing double duty, soon becomes exhausted, and congestion, followed by inflammation, results. When one foot only becomes laminitic, it is customary to find the corresponding member participating at a later date; not always because of sympathy, but because one foot had to do the work of two.
(4) Rapid changes of temperature act as an exciting cause of laminitis by impairing the normal blood supply.
This change of temperature may be induced by drinking large quantities of cold water while in an overheated condition. Here the internal heat is rapidly reduced, the neighboring tissues and blood vessels constrained, and the blood supply to these organs greatly diminished, while the quantity sent to the surface is correspondingly increased. True, in many cases there has not been sufficient labor performed to impair the powers of the laminæ, and laminitis is more readily induced than congestion or inflammation of the skin or other surface organs, because the laminæ can not relieve themselves of threatened congestion by the general safety valve of perspiration. A cold wind or relatively cold air allowed to play upon the body when heated and wet with sweat has virtually the same result, for it arrests evaporation and rapidly cools the external surface, thereby determining an excess of blood to such organs and tissues as are protected from this outside influence. In many instances this happens to be some of the internal organs, as the lungs, if the previous work has been rapid and their functional activity impaired; but in numerous other instances the determination is toward the feet, and that it is so depends upon two very palpable facts: First, that these tissues have been greatly excited and are already receiving as much blood as they can accommodate consistently with health; second, even though these tissues are classed with those of the surface, their protection from atmospheric influences by means of the thick box of horn incasing them renders them in this respect equivalent to internal organs.
A more limited local action of cold may excite this disease, by driving through water or washing the feet and legs while the animal is warm or just in from work. Here a very marked reaction takes place in the surface tissues of the limbs, and passive congestion of the foot results from an interference with the return flow of blood which is being sent to these organs in excess. These are more liable to be simple cases of congestion, soon to recover, yet they may become true cases of laminitis.
(5) Why it is that certain kinds of grain will cause laminitis does not seem to be clearly understood. Certainly they possess no specific action upon the laminæ, for all animals are not alike affected; neither do they always produce these results in the same animal. Some of these feeds cause a strong tendency to indigestion, and the consequent irritation of the alimentary canal may be so great as to warrant the belief that the laminæ are affected through sympathy. In other instances there is no apparent interference with digestion nor evidence of any irritation of the mucous membranes, yet the disease is in some manner dependent upon the feed for its inception. Barley, wheat, and sometimes corn are the grains most liable to cause this disease. With some horses there appears to be a particular susceptibility to this influence of corn, and the use of this grain is followed by inflammation of the feet, lasting from a few days to two weeks. In these animals, to all appearances healthy, the corn neither induces colic, indigestion, nor purging, and apparently no irritation whatever of the alimentary canal.
(6) Fortunately purgative medicines rarely cause inflammation of the laminæ. That it is, then, the result of sympathetic action is no doubt more than hypothetical, for when there is no derangement of the alimentary canal a dose of cathartic medicine will at times bring on severe laminitis.
(7) Almost all the older authorities were agreed that metastatic laminitis is a reality. In my opinion metastatic laminitis is nothing more nor less than concurrent laminitis, and presents little in any way peculiar outside the imperfectly understood exciting cause. The practitioner who allows the acute symptoms of the laminitis to mislead him, simply because their severity has overshadowed those of the primary disease, may lose his case through unguarded subsequent treatment. This form of laminitis is by no means commonly met with. It may be found in conjunction with pneumonia, according to Youatt with inflammation of the bowels and eyes, and according to Law and Williams sometimes with bronchitis.
Symptoms.—Laminitis is characterized by a congregation of symptoms so well marked as scarcely to be misinterpreted by the most casual observer. They are nearly constant in their manifestations, modified by the number of feet affected, the cause which has induced the disease, the previous condition of the patient, and the various other influences which to some extent operate in all diseases. They may be divided into general symptoms, which are concomitants of all cases of the disease, subject to variations in degree only, and special symptoms, or those which serve to determine the feet affected and the complications which may arise.
General symptoms.—Usually, the first symptom is the interference with locomotion. Occasionally the other symptoms are presented first. As the lameness develops the pulse becomes accelerated, full, hard, and strikes the finger strongly; the temperature soon rises several degrees above the normal, reaching sometimes 106° F.; it generally ranges between 102.5° and 105° F. The respirations are rapid and panting in character, the nostrils widely dilated, and the mucous membranes highly injected. The facial expression is anxious and indicative of the most acute suffering, while the body is more or less bedewed with sweat. At first there may be a tendency to diarrhea, or it may appear later as the result of the medicines used. The urine is high colored, scant in quantity, and of increased specific gravity, owing to the water being eliminated by the skin instead of the kidneys. The appetite is impaired, sometimes entirely lost, but thirst is greatly increased. The affected feet are hot and dry, and as much as possible are relieved from bearing weight. Rapping them with a hammer, or compelling the animal to stand upon one affected member, causes intense pain. The artery at the fetlock throbs beneath the finger.
Special symptoms.—Liability to affection varies in the different feet according to the exciting cause. Any one or more of the feet may become the subject of this disease, although it appears more often in the fore feet than in the hind ones. This is due to the difference of the function, i. e., that the fore feet are the bases of the columns of support, receiving nearly all the body weight during progression and consequently most of the concussion, while the hind feet become simply the fulcra of the levers of progression, and are almost exempt from concussion.
One foot.—Injuries and excessive functional performance are the causes of the disease in only one foot. The general symptoms, as a rule, are not severe, there being often no loss of appetite and no unusual thirst, while the pulse, temperature, and respiration remain about normal. The weight of the body is early thrown upon the opposite foot, and the affected one is extended, repeatedly raised from the floor, and then carefully replaced. When made to move forward the lame foot is either carried in the air while progression is accomplished by hopping with the healthy one, or else the heel of the first is placed upon the ground and receives little weight while the sound limb is quickly advanced. Progression in a straight line is more easy than turning toward the lame side.
Both fore feet.—When both fore feet are affected the symptoms are well marked. The lameness is excessive and the animal almost immovable. When standing the head hangs low down, or rests upon the manger as a means of support and to relieve the feet; the fore feet are well extended so that the weight is thrown upon the heels, where the tissues are least sensitive, least inflamed, and most capable of relief by free effusion. The hind feet are brought forward beneath the body to receive as much weight as possible, thereby relieving the diseased ones. If progression is attempted, which rarely happens voluntarily during the first three or four days, it is accomplished with very great pain and lameness at the starting, which usually subsides to an extent after a few minutes' exercise. During this exercise, if the animal happens to step upon a small stone or other hard substance, he stumbles painfully and is excessively lame in the offended member for a number of steps, owing to the acute pain which pressure upon the sole causes in the tissues beneath. The manner of the progression is pathognomonic of the complaint. Sometimes the affected feet are simultaneously raised from the ground (the hind ones sustaining the weight), then advanced a short distance and carefully replaced; at almost the same moment the hind ones are quickly shuffled forward near to the center of gravitation.
In other instances one foot at a time is advanced and placed with the heel upon the ground in the same careful manner, all causes of concussion being carefully avoided. In attempting to back the animal he is found to be almost stationary, simply swaying the body backward on the haunches and elevating the toes of the diseased feet as they rest upon their heels. In attempting to turn either to the right or left he allows his head to be drawn to the one side to its full extent before moving, then makes his hind feet the axis around which the forward ones describe a shuffling circle.
In most of cases of laminitis in the fore feet the animal persists in standing until he is nearly recovered. In other cases he as persistently lies, standing only when necessity seems to compel it, and then for as short a time as possible. If the recumbent position is once assumed, the relief experienced tempts the patient to seek it again; so we often find him down a greater part of the time. But this is not true of all cases; sometimes he will make the experiment, then cautiously guard against a repetition. Even in cases of enforced recumbency, he ofttimes takes advantage of the first opportunity and gets upon his feet, doggedly remaining there until again laid upon his side. How to explain this diversity of action I do not know; theoretically the recumbent position is the only appropriate one, except when complications exist, and the one which should give the most comfort, yet it is rejected by very many patients and, no doubt, for some good reason. It has been suggested as an explanation that when the animal gets upon his feet after lying for a time the suffering is so greatly augmented that the memory of this experience deters him from an attempted repetition. If this were true, the horse with the first attack must necessarily make the experiment before knowing the after effects of lying down, yet many remain standing without even an attempt at gaining this experimental knowledge.
The most-favored position of the animal when down is on the broadside, with the feet and legs extended. While in this position the general symptoms greatly subside; the respirations and pulse become almost normal; the temperature falls and the perspiration dries. It is with difficulty that he is made to rise. When he attempts it he gets up rapidly and "all of a heap," as it were, shifting quickly from one to the other foot until they become accustomed to the weight thrown upon them. Occasionally a patient will get up like a cow, rising upon the hind feet first. Although enforced exercise relieves the soreness to some extent, it is but temporary, for after a few minutes' rest it returns with all its former severity.
Both hind feet.—When only both hind feet are affected, they are, while standing, maintained in the same position as when only the fore ones are the subjects of the disease, but with an entirely different object in view. Instead of being there to receive weight, they are so advanced that the heels only may receive what little weight is necessarily imposed on them; the fore feet at the same time are placed well back beneath the body, where they become the main supports; the animal standing, as Williams describes it, "all of a heap."
Progression is even more difficult now than when the disease is confined to the anterior extremities. The fore feet are dubiously advanced a short distance and the hind ones brought forward with a sort of kangaroo hop that results in an apparent loss of equilibrium which the animal is a few moments in regaining. The general symptoms, or, in other words, the degree of suffering, seem more severe than when the disease affects the fore feet alone. The standing position is not often maintained, the patient seeking relief in recumbency. This fact is easily understood when we consider how cramped and unnatural is the position he assumes while standing and, if it were maintained for any considerable length of time, would, no doubt, excite the disease in the fore feet, as explained by D'Arboval.
All four feet.—Laminitis of all four feet is but uncommonly met with. The author has seen but three such cases. In all these the position assumed was nearly normal. All the feet were slightly advanced, and first one, then another, momentarily raised from the ground and carefully replaced, this action being kept up almost continually during the time the animal remained standing. The suffering is most acute, the appetite lost, and, although the patient lies most of the time, the temperature remains too high. The pulse and respirations are greatly accelerated, the body covered with sweat, and bed sores are unpleasant accompaniments.
Course.—The course which laminitis takes varies greatly in different cases, being influenced more or less by the exciting cause, the animal's previous condition, the acuteness of the attack, and the subsequent treatment. The first symptoms rarely exhibit themselves while the animal is at his work, although we occasionally see the gait impaired by stumbling, the body covered with a profuse sweat, and the respirations become blowing in character as premonitions of the oncoming disease; but, as a rule, nothing amiss with the animal is noted until he has stood for some time after coming in from work, when, in attempting to move him, he is found very stiff. Like all congestions, the early symptoms usually develop rapidly; yet this is not always the case, for often there appears to be no well-defined period of congestion, the disease seemingly commencing at a point and gradually spreading until a large territory is involved in the morbid process.
Simple congestion.—Those cases of simple congestion of the laminæ, which we erroneously call laminitis, are rapidly developed, the symptoms are but moderately severe, and but one to three days are required for recovery. There are no structural changes and but a moderate exudate. This is rapidly reabsorbed, leaving the parts in the same condition as they were previous to the attack. If the congestion has been excessive, a rupture of some of the capillaries will be found, a condition more liable to exist if the animal is made to continue work after a development of symptoms has begun.
True, the majority of these last-described cases prove to be the laminitis in fact, yet the congestion may pass away and the extravasated blood be absorbed without inflammation sufficient to warrant calling it laminitis. The seat of greatest congestion will always be found in the neighborhood of the toe, because of the increased vascularity of that part, and, although at times it is limited to the podophyllous tissue alone, any or all parts of the keratogenous membrane may be affected by the congestion and followed finally by inflammation.
Acute.—In the acute form of laminitis the symptoms may all develop rapidly, or it may commence by the appearance of a little soreness of the feet which in 24 or 48 hours develops into a well-marked case. This peculiarity of development is due to one of two causes. Either the congestion is general, but takes place slowly, or it begins in one or more points and gradually spreads throughout the laminæ. These acute cases generally run their course in from one to two weeks. Usually a culmination of the symptoms is reached, if the patient is properly treated, in from three to five days; then evidences of recovery are discernible in favorable cases. The lameness improves, the other symptoms gradually subside, and eventually health is regained. It is in these cases that a strong tendency to disorganization of a destructive character exists; hence it is we see so many recover imperfectly, with marked structural changes permanently remaining.
Subacute.—Subacute laminitis is most often seen as a termination of the acute form, although it may exist independent of or precede an acute attack. It is characterized by the mildness of its symptoms, slow course, and moderate tissue changes. It may be present a long time before any pathological lesions result other than those found in the acute form, and when these changes do take place they should be viewed rather as complications.
Chronic.—Chronic laminitis is a term used by many to designate any of the sequelæ of the acute and subacute forms of this disease. Pure, chronic inflammation of the laminæ is not very commonly met with, but is most frequent in horses that have long done fast track work. They have "fever in the feet" at all times and are continually sore, both conditions being aggravated by work. Like chronic inflammation of other parts, there is a strong tendency to the development of new connective tissue which, by its pressure upon the blood vessels, interferes with nutrition. Wasting of the coffin bone and inflammation of its covering with caries is not unusual. The continued fever and impaired function of secretion result in the production of a horn deficient in elasticity, somewhat spongy in character, and inclined to crumble. In some cases of "soreness" in horses used to hard or fast work there is evident weakness of the coats of the vessels, brought on by repeated functional exhaustion. Here slight work brings on congestion, which results in serous effusion and temporary symptoms similar to those of chronic laminitis.
Complications.—Complications concurrent with or supervening upon laminitis are frequent and varied, and are often dependent upon causes not fully understood.
Excessive purgation is one of the simplest of these, and not usually attended with dangerous consequences. It rarely occurs unless induced by a purgative, and the excessive action of the medicine is probably to be explained upon the theory that the mucous membrane sympathizes with the diseased laminæ, is irritable, and readily becomes overexcited. The discharges are thin and watery, sometimes offensively odorous, and occasionally persist in spite of treatment. It may prove disastrous to the welfare of the patient by the rapid exhaustion which it causes, preventing resolution of the laminitis, and may even cause death.
Septicemia and pyemia.—Septicemia and pyemia are unusual complications and are seen only in the most severe cases in which bed sores are present or suppuration of the laminæ results. They die, as a rule, within three days after showing signs of the complication.
Pneumonia.—the so-called metastatic—needs no special consideration, for in its lesions and symptoms it does not differ from ordinary pneumonia, although it may be overlooked entirely by the practitioner. Examinations of the chest should be made every day, so as to detect the disease at its onset and render proper aid.
Sidebones.—A rapid development of sidebones is one of the complications, or, perhaps better, a sequel of laminitis not often met with in practice. Here the inflammatory process extends to the lateral cartilages, with a strong tendency to calcification. The deposition of the lime salts is sometimes most rapid, so that the "bones" are developed in a few weeks; in other instances they are deposited slowly and their growth is not noted until long after the subsidence of the laminitis, so that the exciting cause is not suspected. This change in the cartilages may commence as early as the first of the laminitis; and although the trouble in the laminæ is removed in the course of a fortnight the symptoms do not entirely subside, the animal retains the shuffling gait, the sidebones continue to grow, and the patient usually remains quite lame. This alteration of the cartilages generally prevents the patient from recovering his natural gait, and the practitioner receives unjust censure for a condition of affairs he could neither foresee nor prevent.
The laminitic process occasionally extends to the covering of the coronet bone, or at least concurrent with and subsequent to laminitis the development of "low ringbone" is seen, and it is apparently dependent upon the disease of the laminæ for its exciting cause. The impairment of function and consequent symptoms are much less marked here than in sidebones. The coronet remains hot and sensitive and somewhat thickened after the laminitis subsides, and a little lameness is present. This lameness persists, and the deposits of new bone may readily be detected.
Suppuration of the sensitive membrane is a somewhat common complication, and even when present in its most limited form is always a serious matter; but when it becomes extensive, and especially when the suppurative process extends to the periosteum, the results are liable to be fatal. When suppuration occurs the exudation does not appear to be excessive. It is rich in leucocytes and seems to have caused detachment of the sensitive tissues from the horn prior to the formation of pus in some instances; in others the tissues are still attached to the horn, and the suppuration takes place in the deeper tissues.
Limited suppuration may take place in any part of the sensitive tissues of the foot during laminitis, and may ultimately be reabsorbed instead of being discharged upon the surface, but generally the process begins in the neighborhood of the toe and spreads backward and upward toward the coronet, finally separating the horn from the coronary band at the quarters. At the same time it spreads over the sole and eventually the entire hoof is loosened and sloughs away, leaving the tissues beneath entirely unprotected. In other instances—and these are generally the cases not considered unusually severe—the suppuration begins at the coronary band. It extends but a short distance into the tissues, yet destroys the patient by separating the hoof from the coronary band, upon which it depends for support and growth. This form of the suppurative process usually begins in front. It is this part of the coronary band that is always most actively affected with inflammation, and consequently it is here that impairments first occur.
Suppuration of the sensitive sole is more common than of the sensitive laminæ and coronary band. It is present in the majority of cases in which there is a dropping of the coffin bone, and in other instances when the effusion at this point is so great as to arrest the production of horn and uncover the sensitive tissues. Except when the result of injury it begins at the toe and spreads backward, and, if not relieved by opening the sole, escapes at the heel. Suppuration of the sole is much less serious than in other parts of the foot.
If the acute constitutional symptoms developed from sloughing of the foot do not result in death, a new hoof of very imperfect horn may be developed after a time; but unless the animal is to be kept for breeding purposes alone the foot will ever be useless for work and death should relieve the suffering. When only the sole sloughs, recovery takes place with proper treatment.
Peditis.—This is the term that Williams applies to that serious complication of laminitis in which not only the laminæ, but the periosteum membrane covering the bone and coffin bone also are subjects of the inflammatory process. Neither is this all; in some of these cases of peditis acute inflammation of the coffin joint is present, and occasionally suppuration of the joint. A mild form of periostitis, in which the exudation is in the outer layer of the periosteum only, is a more common condition than is recognized generally by practitioners. Intimate contiguity of structures is the predisposing cause, for the disease either spreads from the original seat or the complication occurs as one of the primary results of the exciting cause. In the severer cases in which the exudate separates the periosteum from the bone, suppuration, gangrene, and superficial caries are common results. If infiltration of the bone tissues is rapid the blood supply is cut off by pressure upon the vessels and death of the coffin bone follows. Grave constitutional symptoms mark these changes, which soon prove fatal.
In the mild cases of periostitis it is by no means easy positively to determine its presence, for there are no special symptoms by which it may be distinguished from pure laminitis. In a majority of acute cases, though, which show no signs of improvement by the fifth to seventh day, it is safe to suspect periostitis, particularly if the coronets are very hot, the pulse full and hard, and the lameness acute. In the fortunately rare cases in which the bone is affected with inflammation and suppuration the agony of the patient is intense; he occupies the recumbent position almost continually, never standing for more than a few minutes at a time; suffers from the most careful handling of the affected feet; maintains a rapid pulse and respiration, high temperature, loss of appetite, and great thirst. It is in these cases that the patient continually grows worse, and the appearance of suppuration at the top of the hoof in about two weeks after the inception of the disease proves the inefficiency of any treatment which may have been used and the hopelessness of the case. These patients die usually between the tenth and twentieth days either from exhaustion or pyemic infection.
Gangrene occurs in the periosteum as the result of excessive detachment from the bone and compression due to excessive exudation. Other parts of the sensitive tissues are subject occasionally to the same fate, and at times large areas will be found dead.
Pumiced sole is that condition in which the horny sole in the neighborhood of the toe readily crumbles away and leaves the sensitive tissues more or less exposed. It is not a complication of laminitis only, for it is seen under other conditions. Williams has described the horny tissue of pumiced sole as "weak, cheesy, or spongy, like macerated horn, or even grumous (thick, clotted)." Crumbling horn, when critically examined, shows almost an entire absence of the cohesive matter which unites the healthy fibers, while the fibers themselves are irregular and granular in appearance. Pumiced sole depends upon an impairment of the horn-secreting powers of the sensitive sole or upon a separation of the horny from the soft tissues which maintain its vitality.
Punctured wounds of the foot, accompanied with any considerable destruction of the soft tissues, present the same peculiarities of horn in the immediate neighborhood of the injury. Bruises of the sole are followed by this change when the exudation has been excessive and has separated the horn from the living tissues. True, in these cases we rarely see the soft tissues laid bare, for the reason that new horn is constantly secreted and replaces that undergoing disintegration.
Laminitis presents three conditions under which pumiced sole may appear: First, when free exudation separates the horn from the other tissues, or when the process of inflammation arrests the production of horn by impairing or destroying the horn-secreting membrane; second, when depression of the coffin bone causes pressure upon and arrests the formation of horn; and, third, when the elevation of the sole compresses the soft tissues against the pedal bone and induces the same condition.
Pumiced sole, from simple exudation and separation of tissues, is of little importance for the reason given above in connection with bruises; but when suppuration occurs in restricted portions of the foot in conjunction with laminitis, it always lays bare the tissues beneath and temporarily impairs the animal's value. Recovery takes place after a few weeks by the tissues "horning over," as in injuries attended by the same process. Depression of the coffin bone is not sufficient within itself to cause pumiced sole; for, if the relative change in the bone takes place slowly, or if the horn is thin, the sole becomes convex from gradual pressure and the soft tissues adapt themselves to the change without having their function materially impaired. But when the dropping is sudden and the soft tissues are destroyed, the horn rapidly crumbles away and the toe of the bone comes through. In many of these cases the soft tissues remain uncovered for months. When they are eventually covered it is with a thin, slightly adherent horn that stands but little or no wear. The sole being now convex, the diseased tissues bear unusual weight by coming in contact with the ground, and hence it is that these animals are generally incurable cripples.
In most cases in which the sole is raised to meet the pedal bone and pumiced sole occurs it is due not to pressure of the bone from within (for the tissues are capable of adapting themselves to the gradual change) but to impaired vitality of the sensitive tissues from the inflammation and to the constant concussion and pressure applied from without during progression. To this is to be added the paring away of the horn when applying the shoe, thereby keeping the sole at this point too thin.
Turning up of the toe.—In many cases of laminitis which have become chronic it is found that the toe of the foot turns up; that the heels are longer than natural; while the hoof near the coronary band is circled with ridges like the horn of a ram. Even in cases in which recovery has taken place, and in other diseases than laminitis, these ridges may be found in the wall of the foot. In such cases, however, the ridges are equally distant from one another all around the foot, while in turning up of the toe the ridges are wide apart at the heels and close together in front, as seen in the figure. (Plate XXXVII, fig. 4.) These ridges are produced by periods of interference with the growth of horn alternating with periods during which a normal or nearly normal growth takes place. When the toe turns up it is because the coronary band in front produces horn very slowly, while at the heels it grows much faster, causing marked deformity.
Animals so affected always place the abnormally long heel first upon the ground, not alone because the heel is too long, nor as in acute or subacute laminitis to relieve the pain, but for the reason that the toe is too short and lifted away from its natural position. To bring the toe to the ground the leg knuckles at the fetlock joint.
The pain and impairment of function in these cases always result in marked atrophy of the muscles of the forearm and shoulder, and to some extent of the pectorals, while the position of the fore legs advances the shoulder joints so far forward as to cause a sunken appearance of the breast, which the laity recognize as "chest founder."
The lesions of turning up of the toe are permanent, and are the most interesting pathologically of all the complications of laminitis.
Treatment.—The treatment of laminitis is probably more varied than of any other disease, and yet a large number of cases recover for even the poorest practitioner.
Prevention.—To guard against and prevent disease, or to render an unpreventable attack less serious than it otherwise would be, is the highest practice of the healing art. In a disease so prone to result from the simplest causes, especially when the soundest judgment may not be able to determine the extent of the disease-resisting powers of the tissues which are liable to be affected, or of what shall in every instance constitute an overexcitement, it is not strange that horse owners find themselves in trouble from unintentional transgression. If the disease were dependent upon specific causes, or if the stability of the tissues were of a fixed or more nearly determinate quality, some measures might be instituted that would prove generally preventive; but the predisposing causes are common conditions and often can not be remedied. That which is gentle work in one instance may incite disease in another. That which is feed to-day may to-morrow prove disastrous to health. Finally, necessary medical interference, no matter how judicious, may cause a more serious complaint than that which was being treated. Notwithstanding these difficulties there are some general rules to be observed that will in part serve to prevent the development of an unusual number of cases. First of all the predisposing causes must be removed when possible; when impossible, unusual care must be taken not to bring an exciting cause into operation. Under no circumstances should fat animals have hard work. If the weather is warm or the variation of temperature great, all horses should have but slow, gentle labor until they become inured to it, the tissues hardened, and their excitability reduced to a minimum. Green horses should have moderate work, particularly when taken from the farm and dirt roads to city pavements; for under these circumstances increased concussion, changed hygienic conditions, and artificial living readily become active causes of the disease. Army horses just out of winter quarters, track horses with insufficient preparation, and farmers' horses put to work in the spring are among the most susceptible classes, and must be protected by work that is easy and gradual. If long marches or drives are imperative, the incumbrances must be as light as possible and the journey interspersed with frequent rests, for this allows the laminæ to regain their impaired functional activity and to withstand much more work without danger. Furthermore, it permits early detection of an attack, and prevents working after the disease begins, which renders subsequent medication more effective by cutting the process short at the stage of congestion.
All animals when resting immediately after work should be protected from cold air or drafts. If placed in a stable that is warm and without draft, no covering is necessary; under opposite conditions blankets should be used until the excitement and exhaustion of labor have entirely passed away. It is still better that all animals coming in warm from work be "cooled out" by slow walking until the perspiration has dried and the circulation and respiration are again normal. Animals stopped on the road even for a few moments should always be protected from rapid change of temperature by appropriate clothing. If it can be avoided, horses that are working should never be driven or ridden through water. If unavoidable, they should be cooled off before passing through, and then kept moving until completely dried. The same care is to be practiced with washing the legs in cold water when just in from work, for occasionally it proves to be the cause of a most acute attack of this disease. Unusual changes in the manner of applying the shoes should not be hastily made. If a plane shoe has been worn, high heels or toes must not be substituted at once; but the change, if necessary, should gradually be made, so that the different tissues may adapt themselves to the altered conditions. If radical changes are imperative, as is sometimes the case, the work must be so reduced in quantity and quality that it can not excite the disease.
Laminitis from the effects of purgatives can scarcely be guarded against. I can not determine from the cases in which I have seen this result that there are any conditions present that would warn us of danger. The trouble does not seem to depend upon the size of the purgative, the length of time before purgation begins, or the activity and severity with which the remedy acts. Medicines known to have unusually irritating effects on the alimentary canal should be used only when necessity demands it, and then in moderate doses.
Experience alone will determine what animals are liable to suffer from this disease through the use of feeds. When an attack can be ascribed to any particular feed it should be withheld, unless in small quantities. Horses that have never been fed upon Indian corn should receive but a little of it at a time, mixed with bran, oats, or other feed, until it has been determined that no danger exists. Corn is less safe in warm than in cold weather, and for this reason it should always be fed with caution during spring and summer months.
When an animal is excessively lame in one foot the shoe of the opposite member should be removed, and cold water frequently applied to the well foot. At the same time, if the subject remains standing, the slings should be used. Horses should under no circumstances be overworked; to guard against this, previous work, nature of roads, state of weather, and various other influences must be carefully considered. Watering while warm is a pernicious habit, and, unless the animal is accustomed to it, is liable to result in some disorder, ofttimes in laminitis.
Curative measures.—In cases of simple congestion of the laminæ the body should be warmly clothed and warm drinks administered. The feet should be placed in a warm bath to increase the return flow of blood. In course of an hour the feet may be changed to cold water and kept there until recovery is completed. If the constitutional symptoms demand it, diuretics should be given. Half-ounce doses of saltpeter three times a day in the water answer the purpose. In cases of active congestion the warm footbaths should be omitted and cold ones used from the commencement. Subacute laminitis demands the same treatment, with laxatives if there is constipation, and the addition of low-heeled shoes. The diuretics may need to be continued for some time and their frequency increased. Regarding acute laminitis, what has been called the "American treatment" is simple and efficient. It consists solely in the administration of large doses of nitrate of potash and the continued application to the feet and ankles of cold water.
Three to four ounces of saltpeter in a pint of water, repeated every six hours, is a proper dose. The laminitis frequently subsides within a week. These large doses may be continued for a week without danger. Under no circumstances have I seen the kidneys irritated to excess or other unfavorable effects produced.
The feet should be kept in a tub of water at a temperature of 45° to 50° F., unless the animal is lying down, when swabs are to be used and wet every half hour with the cold water. The water keeps the horn soft and moist and acts directly upon the inflamed tissues by reducing the temperature. Cold maintains the vitality and disease-resisting qualities of the soft tissues, tones up the coats of the blood vessels, diminishes the supply of blood, and limits the exudation. Furthermore, it has an anesthetic effect upon the diseased tissues and relieves the pain.
Aconite may be given in conjunction with the niter when the heart is greatly excited and beats strongly. Ten-drop doses, repeated every 2 hours for 24 hours, are sufficient. The use of cathartics is dangerous, for they may excite superpurgation. Usually the niter will relieve the constipation; yet if it should prove obstinate, laxatives may be carefully given. Bleeding, both general and local, should be guarded against. The shoes must be early removed and the soles left unpared.
Paring of the soles presents two objections: First, while it may temporarily relieve the pain by relieving pressure, it favors greater exudation, which may more than counterbalance the good effects. Secondly, it makes the feet tender and subject to bruises when the animal again goes to work. The shoes should be replaced when convalescence sets in and the animal is ready to take exercise. Exercise should never be enforced until the inflammation has subsided; for although it temporarily relieves the pain and soreness it maintains the irritation, increases the exudation, and postpones recovery.
If at the end of the fifth or sixth day prominent symptoms of recovery are not apparent, apply a stiff blister of cantharides around the coronet and omit the niter for about 48 hours. When the blister is well set, the feet may again receive wet swabs. If one blister does not remove the soreness it may be repeated, or the actual cautery applied. The same treatment should be adopted where sidebones form or inflammation of the coronet bone follows. When the sole breaks through, exposing the soft tissues, the feet must be carefully shod with thin heels and thick toes if there is a tendency to walk on the heels, and the sole must be well protected with appropriate dressings and pressure over the exposed parts. When there is turning up of the toe, blistering of the coronet, in front only, sometimes stimulates the growth of horn, but as a rule judicious shoeing is the only treatment that will enable the animal to do light, slow work.
When suppuration of the laminæ is profuse, it is better to destroy your patient at once and relieve his suffering: but if the suppuration is limited to a small extent of tissue, especially of the sole, treatment, as in acute cases, may induce recovery and should always be tried. If from bed sores or other causes septicemia or pyemia is feared, the bisulphite of soda, in half-ounce doses, may be given in conjunction with tonics and such other treatment as is indicated in these diseases.
As to enforced recumbency I doubt the propriety of insisting on it in the majority of cases, for I think the patient usually assumes whatever position gives most comfort. No doubt recumbency diminishes the amount of blood sent to the feet, and may greatly relieve the pain, so that forcing the patient to lie down may be tried, yet should not be renewed if he thereafter persists in standing.
When the animal persistently stands, or constant lying indicates it (to prevent extensive sores), the patient should be placed in slings. When all four feet are affected it may be impossible to use slings, for the reason that the patient refuses to support any of his weight and simply hangs in them. Lastly, convalescent cases must not be returned to work too early, else permanent recovery may never be effected.