HOOF-AIL.
The first symptom of this troublesome malady, known, likewise, as foot-ail, which is ordinarily noticed, is a lameness of one or both of the fore-feet. On daily examining, however, the feet of a flock which have the disease among them, it will readily be seen that the lesions manifest themselves for several days before they are followed with lameness.
The horny covering of the sheep’s foot extends up, gradually thinning out, some way between the toes and divisions of the hoof, and above these horny walls the cleft is lined with skin. When the points of the toes are spread apart, this skin is shown in front, covered with short, soft hair. The back part of the toes, or the heels, can be separated only to a little distance, and the skin in the cleft above them is naked. In a healthy foot, the skin throughout the whole cleft is as firm, dry, and uneroded as on any other part of the animal.
The first symptom of hoof-ail is a slight erosion, accompanied with inflammation and heat of the naked skin in the back parts of the clefts, immediately above the heels. The skin assumes a macerated appearance, and is kept moist by the presence of a sanious discharge from the ulcerated surface. As the inflammation extends, the friction of the parts causes pain, and the sheep limps. At this stage, the foot, externally, in a great majority of cases, exhibits not the least trace of disease, with the exception of a slight redness, and sometimes the appearance of a small sore at the upper edge of the cleft, when viewed from behind.
The ulceration of the surface rapidly extends. The thin upper edges of the inner walls of the hoof are disorganized, and an ulceration is established between the hoof and the fleshy sole. A purulent fetid matter is discharged from the cavity. The extent of the separation increases daily, and the ulcers also form sinuses deep into the fleshy sole. The bottom of the hoof disappears, eaten away by the acrid matter, and the outer walls, entirely separated from the flesh, hang only by their attachments at the coronet. The whole fleshy sole is now entirely disorganized, and the entire foot is a mass of black, putrid ulceration; or, as more commonly happens, the fly has struck it, and a dense mass of writhing maggots cover the surface, and burrow in every cavity.
The fore-feet are generally first attacked; and, most usually but one of them. The animal at first manifests but little constitutional disturbance, and eats as usual. By the time that any considerable disorganization of the structures has taken place in the first foot, and sometimes sooner, the other forefoot is attacked. That becoming as lame as the first, the miserable animal seeks its food on its knees; and, if forced to rise, its strange, hobbling gait betrays the intense agony occasioned by bringing its feet in contact with the ground. There is a bare spot under the brisket, of the size of a man’s hand, which looks red and inflamed. There is a degree of general fever, and the appetite is dull. The animal rapidly loses condition. The appearance of the maggot soon closes the scene. Where the rotten foot is brought in contact with the side, in lying down, the filthy, ulcerous matter adheres to, and saturates the short wool—it being but a month and a half, or two months, after shearing—and maggots are either carried there by the foot, or they are soon generated there. A black crust is speedily formed round the spot, which is the decomposition of the surrounding structures; and innumerable maggots are at work below, burrowing into the integuments and muscles, and eating up the wretched animal alive. The black, festering mass rapidly spreads, and the poor sufferer perishes, apparently in tortures the most excruciating.
Sometimes but one forefoot is attacked, and subsequently one or both hind ones. There is no uniformity in this particular; and it is a singular fact that, when two or even three of the feet are dreadfully diseased, the fourth may be entirely sound. So, also, one foot may be cured, while every other one is laboring under the malady. The highly offensive odor of the ulcerated feet is so peculiar that it is strictly characteristic of the disease, and would reveal its character, to one familiar with it, in the darkest night.
Hoof-ail is probably propagated in this country exclusively by inoculation—the contact of the matter of a diseased foot with the integuments lining the bifurcation of a healthy foot. That it is propagated in some of the ways classed under the ordinary designation of contagion, is certain. That it may be propagated by inoculation, has been established by experiment. The matter of diseased feet has been placed on the skin lining the cleft of a healthy foot under a variety of circumstances—sometimes when that skin is in its ordinary and natural state, sometimes after a very slight scorification, sometimes when macerated by moisture; and under each of these circumstances the disease has been communicated. The same inference may be drawn, also, from the manner in which the disease attacks flocks. The whole, or any considerable number, though sometimes rapidly, are never simultaneously attacked, as would be expected, among animals so gregarious, if the disease could be transmitted by simple contact, inhaling the breath, or other effluvium.
The matter of diseased feet is left on grass, straw, and other substances, and thus is brought in contact with the inner surfaces of healthy feet. Sheep, therefore, contract the disease from being driven over the pastures, yarded on the straw, etc., where diseased sheep have been, perhaps even days, before. The matter would probably continue to inoculate, until dried up by the air and heat, or washed away by the rains. The stiff, upright stems of closely mown grass, as on meadows, are almost as well calculated to receive the matter of diseased feet, and deposit it in the clefts of healthy ones, as any means which could be artificially devised. It is not entirely safe to drive healthy sheep over roads, and especially into washing-yards, or sheep-houses, where diseased sheep have been, until rain has fallen, or sufficient time has elapsed for the matter to dry up. On the moist bottom of a washing-yard, and particularly in houses or sheds, kept from sun and wind and rain, this matter might be preserved for some time in a condition to inoculate.
When the disease has been well kept under during the first season of its attack, but not entirely eradicated, it will almost or entirely disappear as cold weather approaches, and it does not manifest itself until the warm weather of the succeeding summer. It then assumes a mitigated form; the sheep are not rapidly and simultaneously attacked; there seems to be less inflammatory action constitutionally, and in the diseased parts; the course of the disease is less malignant and more tardy, and it more readily yields to treatment. If well kept under the second summer, it is still milder the third. A sheep will occasionally be seen to limp; but its condition will scarcely be affected, and dangerous symptoms will rarely supervene. One or two applications made during the summer, in a manner presently to be described, will suffice to keep the disease under. At this point, a little vigor in the treatment will rapidly extinguish the disease.
Treatment. The preparation of the foot, where any separate individual treatment is resolved upon, is always necessary, at least in bad cases. Sheep should be yarded for the operation immediately after a rain, if practicable, as the hoofs can then be readily cut. In a dry time, and after a night which left no dew upon the grass, their hoofs are almost as tough as horn. They must be driven through no mud, or soft dung, on their way to the yard, which would double the labor of cleaning their feet. The yard should be small, so that they can be easily caught, and it must be kept well littered down, to prevent their filling their feet with their own excrement. If the straw is wetted, their hoofs will not, of course, dry and harden as rapidly as in dry straw. If the yard could be built over a shallow, gravelly-bottomed brook, it would be an admirable arrangement; for this purpose, a portion of any little brook might be prepared, by planking the bottom, and widening it, if desirable. By such means the hoofs would be kept so soft that the greatest and most unpleasant part of the labor, as ordinarily performed, would be in a great measure saved, and they would be kept free from that dung which, by any other arrangement, will, more or less, get into their clefts.
The principal operator seats himself on a chair, having within his reach a couple of good knives, a whetstone, the powerful toe-nippers already described, a bucket of water with a couple of linen rags in it, together with such medicines as may be deemed necessary. The assistant catches a sheep and lays it partly on its back and rump, between the legs of the foreman, the head coming up about to his middle. The assistant then kneels on some straw, or seats himself on a low stool at the hinder extremity of the sheep. If the hoofs are long, and especially if they are dry and tough, the assistant presents each foot to the operator who shortens the hoof with the toe-nippers. If there is any filth between the toes, each man takes his rag from the bucket of water, and draws it between the toes, and rinses it, until the filth is removed. Each then takes a knife, and the process of paring away the horn commences, upon the effectual performance of which all else depends. A glance at the foot will show whether it is the seat of the diseased action. The least experience cannot fail in properly settling this question. An experienced finger, even, placed upon the back of the pastern close above the heel, will at once detect the local inflammation, in the dark, by its heat.
If the disease is in the first stage—that is, if there are merely erosion and ulceration of the cuticle and flesh in the cleft above the walls of the hoof—no paring is necessary. But if ulceration has established itself between the hoof and the fleshy sole, the ulcerated parts, however extensive, must be entirely stripped of their horny covering, no matter what amount of time and care it may require. It is better not to wound the sole so as to cause it to bleed freely, as the running blood will wash off the subsequent application; but no fear of wounding the sole must prevent a full compliance with the rule laid down above. At the worst, the blood will stop flowing after a little while, during which time no application needs to be made to the foot.
If the foot is in the third stage—a mass of rottenness, and filled with maggots—pour, in the first place, a little spirits of turpentine—a bottle of which, with a quill through the cork, should be always ready—on the maggots, and most of them will immediately decamp, and the others can be removed with a probe or small stick. Then remove every particle of loose horn, though it should take the entire hoof, as it generally will in such cases. The foot should next be cleansed with a solution of chloride of lime, in the proportion of one pound of chloride to one gallon of water. If this is not at hand, plunging the foot repeatedly in hot water, just short of scalding hot, will answer every purpose. The great object is to clean the foot thoroughly. If there is any considerable “proud flesh,” it should be removed with a pair of scissors, or by the actual cautery—hot iron.
The following are some of the most popular remedies: Take two ounces of blue vitriol and two ounces of verdigris, to a junk-bottle of wine; or spirits of turpentine, tar, and verdigris in equal parts; or three quarts of alcohol, one pint of spirits of turpentine, one pint of strong vinegar, one pound of blue vitriol, one pound of copperas, one and a half pounds of verdigris, one pound of alum, and one pound of saltpetre, pounded fine; mix in a close bottle, shake every day, and let it stand six or eight days before using; also mix two pounds of honey and two quarts of tar, which must be applied after the preceding compound. Or apply diluted aquafortis—nitric acid—with a feather to the ulcerated surface; or diluted oil of vitriol—sulphuric acid—in the same way; or the same of muriatic acid; or dip the foot in tar nearly at the boiling point.
In the first and second stages of the disease, before the ulcers have formed sinuses into the sole, and wholly or partly destroyed its structure, the best application is a saturated solution of blue vitriol—sulphate of copper. In the third stage, when the foot is a festering mass of corruption, after it has been cleansed as already directed, it requires some strong caustic to remove the unhealthy granulations—the dead muscular structures—and to restore healthy action. Lunar caustic, which is preferable to any other application, is too expensive; chloride of antimony is excellent, but frequently unattainable in the country drug-stores; and muriatic acid, or even nitric or sulphuric acids, may be used instead. The diseased surface is touched with the caustic, applied with a swab, formed by fastening a little tow on the end of a stick, until the objects above pointed out are attained. The foot is then treated with the solution of blue vitriol, and subsequently coated over with tar which has been boiled, and is properly cooled, for the purpose of protecting the raw wound from dirt, flies, etc. Sheep in this stage of the disease should certainly be separated from the main flock, and looked to as often as once in three days. With this degree of attention, their cure will be rapid, and the obliterated structures of the foot will be restored with astonishing rapidity.
The common method of using the solution of blue vitriol is to pour it from a bottle with a quill in the cork, into the foot, when the animal lies on its back between the operators, as already described. In this way a few cents’ worth of vitriol will answer for a large number of sheep. The method is, however, imperfect; since, without extraordinary care, there will almost always be some slight ulcerations not uncovered by the knife, which the solution will not reach, the passages to them being devious, and perhaps nearly or quite closed. The disease will thus be only temporarily suppressed, not cured.
A flock of sheep which were in the second season of the disease, had been but little looked to during the summer, and as cold weather set in, many of them became considerably lame, and some of them quite so. Their feet were thoroughly pared; and into a large washing-tub, in which two sheep could conveniently stand, a saturated solution of blue vitriol and water, as hot as could be endured by the hand even for a moment, was poured. The liquid was about four inches deep on the bottom of the tub, and was kept at that depth by frequent additions of hot solution. As soon as a sheep’s feet were pared, it was placed in the tub, and held there by the neck. A second one was then prepared, and placed beside it; when the third was ready, the first was taken out; and so on. Two sheep were thus constantly in the tub, each remaining some five minutes. The cure was perfect; there was not a lame sheep in the flock during the winter or the next summer. The hot liquid penetrated to every cavity of the foot; and doubtless had a far more decisive effect, even on the uncovered ulcers, than would have been produced by merely wetting them. The expense attending the operation was about four cents per sheep. Three such applications, at intervals of a week, would effectually cure the disease, since every new case would thus be arrested and cured before it would have time to inoculate others. It would, undoubtedly, accomplish this at any time of year, and even during the first and most malignant prevalence of the contagion, provided the paring was sufficiently thorough. The second and third parings would be a mere trifle; and the liquid left at the first and second applications could again be used. Thus sheep could be cured at about twelve cents per head, which is much cheaper, in the long run, than any ordinary temporizing method, where the cost of a few pounds of blue vitriol is counted, but not the time consumed; and the disease is thus kept lingering in the flock for years.
Some Northern farmers drive their sheep over dusty roads as a remedy for this disease; and in cases of ordinary virulence, especially where the disease is chronic, it seems to dry up the ulcers, and keep the malady under. Sheep are also sometimes cured by keeping them on a dry surface, and driving them over a barn-floor daily, which is well covered with quick-lime. It may sometimes, and under peculiar circumstances, be cured by dryness, and repeated washing with soap-suds.
Many farmers select rainy weather as the time for doctoring their sheep. Their feet are then soft, and it is therefore on all accounts good economy, when the feet are to be pared, and each separately treated, provided they can be kept in sheep-houses, or under shelters of any kind, until the rain is over, and the grass again dry. If immediately let out in wet grass of any length, the vitriol or other application is measurably washed away. This is avoided by many, by dipping the feet in more tar—an admirable plan under such circumstances.
A flock of sheep which have been cured of the hoof-ail, is considered more valuable than one which has never had it. They are far less liable to contract the disease from any casual exposure; and its ravages are far less violent and general among them.
This ailment should not be confounded with a temporary soreness, or inflammation of the hoof, occasioned by the irritation from the long, rough grasses which abound in low situations, which is removed with the cause; or, if it continues, white paint or tar may be applied, after a thorough washing.