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.