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United States. Bureau of Animal Industry.

Special report on diseases of cattle and on cattle feeding online

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outward signs of disease appear. These vary very markedly from case
to case, and observers differ more or less in their accounts of the disease
as they have found it. It usually begins with a chill, followed by high
fever (104 to 107 F). The head droops, the skin is hot and dry, and the
coat staring. Quivering of the muscles in various parts of the body is
frequently observed. Marked dullness passing, according to some
observers, into an almost stupefied condition later on, is quite common.
The secretion of milk stops in the beginning of the disease.

Affections of the eyes are characteristic of this malady. Then- is an
abundant formation of tears, which run down over the face. The lids
are swollen and inflamed, and the animal shuns the light by keeping
them closed. This simple inflammation may be followed by an inflam-
mation of the cornea, which may lead to permanent clouding. Inflam-
mation of deeper parts of the eyes (iris) is occasionally seen.

Inflammation of the mucous membrane of the mouth, nose, and the
sinuses pf the head leads to discharges from the nose and mouth. The
mucous membrane of the nose is reddened, and may be covered later on
with inflammatory deposits. The discharge is at first watery, then
thieker, and occasionally streaked with blood and foul smelling. The
inflammation of the mouth is like this and leads to much dribbling of
saliva. It may extend to the nasal pad and 'to the nose. Inflamma-
tion of the throat, with deposits of a croupousor diphtheritic character,
lends to diilicult breathing. Various noises are produced as the air
Mm > in and out, depending on the place where its passage is partly
obstructed by mucus and exudation. If the obstruction is great signs
of suffocation may appear. According to some observers the horns
become loosened by inflammation and may be knocked off easily by the
,sy, blinded animal.

Tlie bowels are at first constipated; later, diarrhea sets in and thedis-
cli;ii us become soft, offensive, and streaked with blood. Some authors
men I ion flic discharge of exudation in the form of membranous patches,
which have been observed to be to 9 feet long. The kidneys are usu-
ally iniiamed, the urine is passed with difficulty and pain, and contains
abnormal elements (albumen, casts, etc.), indicative of disease. The
vaginal mucous membrane may be affected in a manner similar to ttiat
of the mouth and nose, and occasionally abortion follows.

In connection with these various symptoms there may be much un-
ea-inr>s on the part of the animal, leading in some cases to madness and
furious dclirum, in others to spasms and convulsions or paralysis, llapid
emaciation is quite invariably associated with the disease in all its
grades.

Like other infectious diseases, malignant catarrh pursues a longer or
slimier course in accordance with the severity of the attack. In acute
cases death is said to take place from three to seven days after the ap-
pearance of symptoms. When recovery ensues it may take three or



428 DISEASES OF CATTLE.

four weeks. According to statistics, from 50 to 90 per cent of the
affected animals die.

If animals which have died of this disease be examined, there will
be occasionally found, in addition to the changes of the mucous mem-
brane of mouth and nasal cavities referred to above, shallow ulcers iu
these situations. In severe cases membranous (croupous) deposits are
found in the throat. Similar deposits have been found upon the mu-
cous membrane of the fourth stomach and intestine, which is always in-
flamed. There is more or less inflammation of the membranes of the
brain. In countries where rinderpest occasionally appears it may be
difficult to distinguish between it and malignant catarrh, owing to a
general similarity of the symptoms. In such cases only a trained veteri-
narian who takes into consideration all the different symptoms and
lesions of both diseases should decide.

Treatment. There is no specific treatment for this affection, and the
various symptoms may be dealt with, if desired, according to the meth-
ods given in the first part of this volume. Preventive treatment, which
insists on a removal of the infected animals and a thorough cleaning
and disinfection of infected stables, may prevent the subsequent appear-
ance of the disease. If the floors are low and damp they should be
raised and made dry.

SOUTHERN CATTLE FEVER (TEXAS FEVER).

This disease, which is more commonly known as splenetic or Texas
fever, is a specific fever communicated by cattle which have recently
been moved northward from the infected district, or which is con-
tracted by cattle taken into the infected district from other parts of
the world. It is characterized by the peculiarity among animal diseases
that the animals which disseminate the infection are apparently in good
health, while those which sicken and die from it do not as a rule infect
others.

It is accompanied by high fever, greatly enlarged spleen, destruction
of the red blood corpuscles, escape of the coloring matter of the blood
through the kidneys, giving the urine a deep red color, by a yellowness
of the mucous membranes and fat, which is seen more especially in fat
cattle, by a rapid- loss of strength, and by fatal results in a large pro-
portion of cases.

This disease has various names in different sections of the country
where it frequently appears. It is often called Spanish fever, acclima-
tion fever, red- water, black-water, distemper, murrain, dry murrain,
yellow murrain, and bloody murrain.

The earliest accounts we have of this disease date back to 1814,
when it was stated by Dr. James Mease before the Philadelphia So-
ciety for Promoting Agriculture that the cattle from a certain district
in South Carolina so certainly disease all others with which they mix
in their progress to the North, that they are prohibited by the people



INFECTIOUS DISEASES OF CATTLE. ^ 429

of Virginia from passing through the State; that these cattle infect
others while they themselves were in perfect health, and that cattle
from Europe or the interior taken to the vicinity of the sea were
attacked by a disease that generally proved fatal. Similar observa-
tions have been made in regard to a district in the southeastern part
of Virginia, the eastern portion of North Carolina, nearly the whole
of South Carolina, Georgia, Florida, Alabama, Mississippi, Louisiana,
the southern portion of Tennessee, and a large part of Arkansas,
Indian Territory, and Texas. It was the frequent and severe losses
following the driving of cattle from the infected district in Texas into
and across the Western States and Territories which led to the disease
being denominated Texas fever. It is now known, however, that the
infection is not peculiar to Texas or even to the Gulf coast, but that it
extends far inland and northward almost to the southern line of Mary-
land.

When cattle from other sections of the country are taken into the
infected district they contract this disease usually during the first sum-
mer, and if they are adult animals, particularly milch cows or fat cattle,
nearly all die. Calves are much more likely to survive. The disease is
one from which immunity is acquired, and, therefore, calves which
recover are not again attacked, as a rule, even after they become adult.

When the infection is disseminated beyond the permanently infected
district, the roads, pastures, pens, and other inclosures are dangerous
for susceptible animals until freezing weather. The infection then dis-
appears, and cattle may be driven over the grounds or kept in the
im -Insures the succeeding summer and the disease will not reappear.
There are some exceptions to this rule in the section just north of the
boundary line of the infected district. In this locality the infection
sometimes resists the winters, especially when these are mild. There
is some reason for believing that the infected district is gradually extend-
ing toward (he north, but more careful observations need to be made
before safe conclusions on this point can bo adopted.

In regard to the manner in which the disease is communicated, ex-
IMM i< -IK < shows that this does not occur by animals coming near or in
contact with each other. It is an indirect infection. The cattle from
the infected district first infect the pastures, roads, pens, cars, etc., and
the susceptible cattle obtain the virus second hand from these. Usually
animals do not contract disease when separated from infected pastures
by a fence. If, however, there is any drainage or washing by rains
across the line of fence this rule does not hold good.

The investigations made by the Bureau of Animal Industry demon-
strate that the ticks which adhere to cattle from the infected district
are the chief means of conveying the infection to the l>odies of suscepti-
ble cattle. The infection, so far as we know, is not spread by the
saliva, the urine, or the manure of cattle from the infected district. In
studying the causation and prevention of this disease, attention must



430 DISEASES OF CATTLE.

therefore be largely given to the ticks, and it now appears probable
that if the cattle could be freed from this parasite when leaving the
infected district they would not be able to cause the malady. The dis-
covery of the connection of the ticks with the production of the disease
is so recent that it is impossible to predict at this time the influence
which it may have in preventing its spread. It establishes an essen-
tial point, however, and indicates many lines of investigation which
are likely to yield important results.

Nature of the disease** Texas fever is caused by an organism
which lives within the red blood-corpuscles and breaks them up. It
is therefore simply a blood disease. The organism does not belong to
the bacteria but to the protozoa. It is not, in other words, a microscopic
plant, but it belongs to the lowest forms of the animal kingdom. This
very minute organism multiplies very rapidly in the body of the infected
animal, and in acute cases causes an enormous destruction of red corpus-
cles in a few days. How it gets into the red corpuscle it is not possible
to state, but it appears that it enters as an exceedingly minute body,
probably endowed with motion, and only after it has succeeded in enter-
ing the corpuscle does it begin to enlarge. Concerning the more detailed
description of this micro-organism we must refer the reader to the
forthcoming special report on Texas fever. We shall simply delay in
this place to describe its main characters. Plate XLIII, Fig. 4, illustrates
an early stage of this blood parasite. The red corpuscle contains a
very minute roundish body which is stained blue to bring it into view.
The body is as a rule situated near the edge of the corpuscle. Fig. 5
illustrates an older stage in the growth of the parasite, in fact the
largest which has thus far been detected. It will be noticed that there
are usually two bodies in a corpuscle. These bodies are in general
pear shaped. The narrow ends are always toward each other when two
are present in the same corpuscle. If we bear in mind that the average
diameter of the red blood corpuscles of cattle is from. - 4 -oVo to -^Vo inch,
the size of the contained parasite may be at once appreciated by a
glance at the figures referred to.

The various disease processes which go on in Texas fever, and which
we may observe by examining the organs after death, all result from
the destruction of the red corpuscles. This destruction may be ex-
tremely rapid or slow. When it is rapid we have the acute, usually
fatal, type of Texas fever which is always witnessed in the height of the
Texas-lever season; that is, during the latter weeks of August and the
early weeks of September. When the destruction of corpuscles is
slower a mild, usually non-fatal, type of the disease is called forth which
is only witnessed late in autumn or more rarely in July and the early
part of August. Cases of the mild type occurring thus early usually
become acute later on and terminate fatally.

* The investigations from which the facts in the remainder of this article are taken
will be published in full in a forthcoming report of the Bureau of Animal Industry
byDrs, Theobald Smith and F. L. Kilborne.



INFECTIOUS DISEASES OF CATTLE. 431

The acute disease is fatal in most cases, and the fatality is due not so
much to the loss of blood corpuscles as to the difficulty which the or-
gans have in getting rid of the waste products arising from this whole-
sale destruction. How great this may be a simple calculation will
serve to illustrate. If we take a steer weighing 1,000 pounds, the blood
in its body will amount to about 50 pounds, if we assume that the blood
represents one-twentieth of the weight of the body, a rather low esti-
mate. According to experimental determination at the Bureau Station,
which consists in counting the number of blood corpuscles in a given
quantity of blood from day to day in such an animal, the corpuscles con-
tained in from 5 to 10 pounds of blood may be destroyed within twenty-
four hours. The remains of these corpuscles and the coloring matter
in them must either be converted into bile or excreted unchanged. The
it-suit of this effort on the part of the liver causes extensive disease
of this organ. The bile secreted by the liver cells contains so much
solid material that it stagnates in the finest bile canals and chokes these
up completely. This in turn interferes with the nutrition of the liver
cells and they undergo fatty degeneration and perish. The functions
of the liver are thereby completely suspended and death is the result.
This enormous destruction of corpuscles takes place to a large extent
in the kidneys, where a great number of corpuscles containing thepara-
>ite> arc always found in acute cases. This accounts largely for the
blood-colored urine or red water which is such a characteristic feature
of Texas fever. The corpuscles themselves are not found in the urine;
it is the red coloring matter or hemoglobin which leaves them when they
break np and passes into the urine.

Xymptom*. After a period of exposure to infected soil, which may
vary from thirteen to ninety days, and which will be more fully dis-
1 im-t her on, under the subject of cattle ticks as bearers of the
ver parasite, the disease first shows itself in dullness, loss of
appetite, and a tendency to leave the herd and stand or lie down alone.
A few days before these symptoms appear the presence of r, high fever
may be detected by the clinical thermometer. The temperature i
from a normal of 101Q-103O F. to 10<P and 107 F. There seems to be
little or no change in temperature until recovery or deatli ensues. The
period of high temperature or fever varies considerably. As it indi-
cates the intensity of the disease process going on within, the higher it
is t lie more rapid the fatal end. When it does not rise above 104 F. the
disease is milder and more prolonged.

The bowels are mostly constipated during the fever; towards the end
the tcces may become softer and rather deeply tinged with bile. The
mine shows nothing abnormal during the course of the disease until
near the fatal termination, when it may be deeply stained with the'col-
oring matter of the blood. (Hemoglobinuria; see Plate XLIII, Fig. 3.)
Although this symptom is occasionally observed in animals which
reeo\er. yet it may generally be regarded as an indication of approach-



432 DISEASES OF CATTLE.

ing death. The pulse and respiration are usually much more rapid
than during health.

Other symptoms in addition to those mentioned have been described
by observers, but they do not seem to be constant, and only the above
are nearly always present. As the end approaches emaciation becomes
very marked, the blood is very thin and watery, and the closing of any
wound of the skin by clots is retarded. The animal manifests increas-
ing stupor and may lie down much of the time. Signs of delirium have
been observed in some cases. Death occurs most frequently in the
night.

The course of the disease is very variable in duration. Death may
ensue in from three days to several weeks after the beginning of the
fever. Those that recover ultimately do so very slowly, owing to the
great poverty of the blood in red corpuscles. The flesh is regained but
very gradually, and the animal may be subjected to a second though
mild attack later on in the autumn, which pushes the full recovery on-
ward to the beginning of winter.

In the mild type of the disease, which occurs in October and Novem-
ber, symptoms of disease are well nigh absent. There is little if any
fever, and if it were not for loss of flesh and more or less dullness the
disease might pass unnoticed, as it undoubtedly does in a majority of
cases. If, however, the blood corpuscles be counted from time to time
a gradually diminishing number will be found, and after several weeks
only about one-fifth or one-sixth of the normal number are present. It
is, indeed, surprising how little impression upon the animal this very
impoverished condition of the blood appears to make. It is probable,
however, that if two animals kept under the same conditions, one healthy
and the other at the end of one of these mild attacks, be weighed, the
difference would be plainly shown.

Pathological changes observable after death. In the preceding pages
some of these have already been referred to in describing the nature
of the disease. It is very important at times to determine whether a
certain disease is Texas fever or some other disease, like anthrax, for
example. This fact can, as a rule, be determined at once by a thorough
microscopic examination of the blood. The necessary apparatus and
the requisite qualifications for this task leave this method entirely in
the hands of experts. There is, however, a considerable number of
changes caused by this disease, which may be detected by the naked
eye when the body has been opened. These, put together, make a mis-
take quite impossible. The presence of small ticks on the skin of the
escutcheon, the thighs, and the udder is a very important sign in herds
north of the Texas fever -line, as it indicates that they have been brought
in some manner from the South and carried the disease with them, as
will be explained later. Another very important sign is the thin, watery
condition of the blood, either just before death or when the fever has
been present for four or five days. A little incision into the skin will



INFECTIOUS DISEASES OF CATTLE. 43 &

enable anyone to determine this point. Frequently the skin is so poor
in blood that it may require several incisions to draw a drop or more.

The changes in the internal organs, as found on post-mortem exami-
nations, are briefly as follows: The spleen or inilt is much larger than
in healthy animals. It may weigh three or four times as much. When
it is incised the contents or pulp is blackish (see Plate XLII, Fig. 1), and
may even well out as a disintegrated mass. The markings of the
healthy spleen (Fig. 2) are all effaced by the enormous number of blood
corpuscles which have collected in the spleen and to which the enlarge-
ment is due. Next to the spleen the liver will arouse our attention.
(See Plate XLIII, Fig. 2.) It is larger than in the healthy state, has lost
its natural brownish color (Fig. 1), and now has on the surface a paler
yellowish hue. When it is incised this yellowish tinge or mahogany
color, as it has been called by some, is still moro prominent. This is
due to the large amount of bile in the finest bile capillaries, and as
these are not uniformly filled with it the cut surface has a mere or less
mottled appearance. This bile injection causes in many cases a fatty
degeneration of the liver cells, which makes the organ appear still
lighter in color.

In all cases the gall bladder should be examined. This is distended
with bile, which holds in suspension a large quantity of yellow flakes,
so that when it is poured into a tall bottle to settle fully one-half or more
of the column of fluid will be occupied by a layer of flakes. If mucus
is present at the same time the bile may become so viscid that when it
is poured from one glass to another it forms long bauds. The bile in
health is a limpid fluid containing no solid particles.

If the animal has not been observed during life to pass urine colored
witli blood or red water, the bladder should be opened. This quite
invariably, in acute cases, contains urine which varies in color from a
deep port wine to a light claret. In many cases the color is so dense
that light will not pass through even a thin layer. (Plate XLIII, Fig. 3.)
The kidneys are always found congested in the acute attack. The dis-
ease exerts but little effect on the stomach and intestines beyond more
or less reddening of the mucous membrane. Hence an examination of
these may be safely omitted. The lungs are, as a rule, not diseased.
The heart usually shows patches of blood extravasation on the inside
(left ventricle), and less markedly on the outer surface.

We have observed jaundice of the various tissues but very rarely.
It has been observed by some quite regularly, however.

The cattle tick, Ixode* borix (Riley) Boophilu* borix (Curtice), a* the
carrier of Texan fever. (Plato XLIV.) The cattle tick is, as its name
indicates, a parasite of cattle in the southern part of the United States.
It belongs to the group of Artliropoda and to the, genus Ij-odcs (Boo-
philit*), which is included in the order Acarina. Its life history is quite
simple and easily traced from one generation to another. It is essen-
tially a parasite, attaching itself to the skin suul drawing the blood of
24097 28



434 DISEASES OF CATTLE.

its host. It is unable to come to maturity and reproduce its kind
unless it becomes attached to the skin of cattle, whence it may obtain
its food.

The eggs laid on the ground after the female has dropped from the
host begin to develop at once. When the embryo is fully formed within
the shell it ruptures this and gains its freedom. The time required
from the laving of the eggs to their hatching varies considerably
according to the temperature. In the laboratory in the heat of mid-
summer this was accomplished in about thirteen days. In the late fall
under the same conditions, it required from four to six weeks. The
larva after emerging from the egg is very minute, six-legged, and just
visible to the naked eye. (Plate XLIV, Fig. 3.) If these larvae be kept on
a layer of moist sand or earth in a covered dish they may remain alive
for mouths, but there is no appreciable increase in size. As soon, how-
ever, as they are placed upon cattle growth begins.

On pastures these little creatures soon iind their way upon cattle.
They attach themselves by preference to the tender skin on the escutch-
eon, the inside of the thighs, and on the base of the udder. Yet when
they are very numerous they may be found, in small numbers, on vari-
ous parts of the body, such as the neck, the chest, and the ears.

The changes which they undergo during their parasitic existence
were first studied by Dr. Cooper Curtice in 1889. The young tick
within a week molts and the second or nymphal stage of the parasite's
life is thus ushered in. After this change it has four pairs of legs.
Within another week another molt takes place by which the tick passes
from the nymphal to the sexual or adult stage. Impregnation now
takes place, and with the development of the ova in the body the ani-
mal takes an increased quantity of blood, so that it becomes very much
larger in a Few days. That the rapid growth is due to the blood taken
in may be easily proved by crushing one. The intestine is distended
with a thick tarry mass composed of partly digested blood. When the
female has reached a certain stage of maturity it drops to the ground
and begins to lay a large number of eggs, which hatch in the time given
aboA 7 e.

The life of the cattle tick is thus spent largely on cattle, and although
the young or larva? may live for a long time on the ground in the sum-
mer season they can not mature excepting as parasites on cattle. We
have purposely omitted various details of the life history, including that
of the male, as they are not necessary to an understanding of our pres-
ent subject Texas fever. How this is transmitted we will proceed to
consider.

Southern cattle sent north during the spring and summer months
carry on their bodies large numbers of the cattle tick. These when
matured drop off and lay their eggs on northern pastures. These hatch,



Online LibraryUnited States. Bureau of Animal IndustrySpecial report on diseases of cattle and on cattle feeding → online text (page 50 of 56)