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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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nature which have the power of indefinite multiplication and of setting
free certain peculiar poisons which are chiefly responsible for the nior
bid changes.

This definition might include diseases due to certain animal para-
sites, such as trichina', for example, which multiply in the digestive
tract, but whose progeny is limited to a single generation. Py mininnn
consent the term infectious is restricted to those diseases caused by

371



372 DISEASES OF CATTLE.

the invasion and multiplication of certain very minute unicellular
organisms included under the general classes of bacteria and protozoa.
Nearly all the diseases of cattle, for which a definite cause has been
traced, are due to bacteria. Among these are tuberculosis, anthrax,
black quarter, and tetanus (or lockjaw). Only one, Texas fever, is
traceable to protozoa, and one, actinomycosis, to a fungus. Those dis-
eases, of which the cause is unknown or imperfectly worked out, are
pleuro-pneumonia, rinderpest, foot-and-mouth disease, rabies, cowpox,
malignant catarrh, and dysentery.

Bacteria may be defined as very minute, unicellular organisms of a
plant-like character. Their form is very simple, as may be seen from
an inspection of the various species depicted on Plate xxix. The
description of these figures will be found at the end of this article.
The magnification there given will furnish the reader some idea of
their very minute size. They multiply in two ways. The bacterium
elongates and then divides in the middle to form two daughter cells.
These go through the same process at once and thus four cells are pro-
duced. The division of these leads to 8, the division of 8 to 16, and so
on indefinitely. The rapidity with which this multiplication takes
place depends upon the nature of the bacterium. The bacillus of
tuberculosis multiplies very slowly, while that of anthrax multiplies
with great rapidity, provided both are in the most favorable condition.
Another mode of reproduction, limited to certain classes of bacteria,
consists in the formation of a spore within the body of the bacterium.
Spore formation usually takes place when the conditions pertaining to
the growth of the bacteria become unfavorable. The spores are much
more resistant to destructive agents than the bacteria which produced
them. The anthrax spore may live several years in a dried state, but
the anthrax bacillus perishes in a few days under like conditions.
This matter will be referred to again when we come to discuss the sub-
ject of disinfection.

Of the protozoa which cause disease very little is at present known.
The one which produces Texas fever is pictured on Plate XLIII, in Figs.
4 and 5. These parasites have a more complex life history than bac-
teria, and as they can not be grown in artificial media their thorough
investigation is at present hampered with great difficulties.

The differences in the symptoms and lesions of the various infectious
diseases are due to differences in the respective organisms causing
them. Similarly the great differences observed in the sources from
which animals become infected and the manner in which infection takes
place are due to differences in the life history of these minute organ-
isms. Much discussion has taken place of late years concerning the
precise meaning of the words infection and contagion. But these
words are now wholly inadequate to express the complex processes of
infection, and it may be said that each species of bacterium or proto-
zoon has its own peculiar way of invading the animal body, differing



INFECTIOUS DISEASES OF CATTLE. 373

more or less from all the rest. There are, however, a few broad dis-
tinctions which may be expressed with the help of these old terms.
Infection, as laid down above, refers at present in a comprehensive
way to all microorganisms capable of setting up disease in the body.
Some microorganisms are transmitted directly from one animal to
another, and the diseases produced may be called contagious. Among
these are included pleuro-pneumonia, rinderpest, foot-and-mouth dis-
ease, rabies, cowpox, and tuberculosis. Again, certain organisms are
perhaps never transmitted from one animal to another, but may come
from the soil. Among these are tetanus, black quarter, anthrax, to a
large extent, and perhaps actinomycosis in part. These diseases accord-
ing to some authorities may be called miasmatic. There is a third class
of infectious diseases of which the specific bacteria are transmitted
from one animal to another, as with the contagious diseases, but the
bacteria may, under certain favorable conditions, find enough food in
the soil and the surroundings of animals to multiply to some extent
after they have left the sick before they gain entrance into a healthy
animal.

This general classification is subject to change if we take into consid-
eration other characteristics. Thus tuberculosis wo old not by many
be considered contagious in the sense that foot-and-mouth disease is,
because of the insidious beginning and slow course of the disease. Yet
the bacillus, must come from preexisting disease in either case. The
disease of rabies or hydrophobia is not contagious in the sense that
rinderpest is, because the virus of rabies must be inoculated into a
wound before it can take effect. Yet, in both cases, the virus passes
without modification from one animal to another, though in different
ways.

Again, all the diseases under the second group, which seem to come
from the soil and from pastures, are in one sense contagious in that the
virus may be taken from a sick animal and inoculated directly into a
healthy animal with positive result. Other illustrations may be cited
which show that these old terms are not in themselves satisfactory.
There are so many conditions which enter into the process of infection
that no single classification will give a sufficiently correct or compre-
hensive idea, of it. These statements will be easily understood if the
different infectious diseases in the following pages be studied with ref-
erence to the way or ways in which each disease may be contracted.
Enough has been said, therefore, to show that if we wish to make our-
selves acquainted with the dangers of any given disease we must study
that disease and not rely upon any single word to tell the whole story.

Infectious diseases have, OH a general rule, a period of incubation
which comprises the time elapsing between the infection and the actual
appearance of the disease. This period varies with the malady. The
most common symptom of this class of diseases is fever. The seventy
of the fever is measured by the temperature of the animal and this is



374 DISEASES OF CATTLE.

readily and accurately ascertainable by the clinical thermometer. (See
Plate in, Fig. 1.) The other symptoms are variable and depend upon
the particular organ or organs most implicated. Loss of appetite,
cessation of rumination and milk secretion, and general dullness are
symptoms quite invariably present in most infectious diseases.

Secondary diseases or complications may arise during the course of
infectious diseases which are largely due to bacteria other than those
producing the original malady. These complications are often so severe
as to become fataL In general it may be stated that they are due to
filthy surroundings, and hence cleanliness may become an important
aid to recovery.

The treatment of infectious diseases is given under each malady so
far as this is allowable or advisable. These diseases are not, as a rule,
amenable to treatment. When the symptoms have once appeared the
disease is apt to run its course in spite of treatment, and if it is one
from which animals usually recover, all that can be done is to put them
into the most favorable surroundings. Many infectious diseases lead
sooner or later to death, and treatment is useless so far as the sick are
concerned. But it may be worse than useless for those not yet in-
fected. All animals suffering with infectious diseases are a menace to
all others more or less directly. They represent for the time being
manufactories of disease germs, and they are giving them off more or
less abundantly during the period of disease. They may infect others
directly or they may scatter the virus about, and the surroundings may
become a future source of infection for healthy animals. This leads us
to the subject of prevention, as the most important of all which claim
our attention. In this place only a few general remarks will suffice to
bring the subject before the reader.

The most important thing is to keep disease away from a herd or
farm. To do this all sick or suspicious animals should be avoided. A
grave form of disease may be introduced by apparently mild or trivial
cases brought in from without. It is generally conceded that continual
change and movement of animals are the most potent means by which
infectious diseases are disseminated.

With some cattle diseases, such as anthrax, black quarter, and pleuro-
pueumonia, preventive inoculation is resorted to in some countries. This
may be desirable when certain diseases have become stationary in any
locality so that eradication is impossible. It should not be practiced
in territories where a given disease may still be extirpated by ordinary
precautions. Preventive inoculation is applicable to only a few mal-
adies, and therefore its aid in the control of diseases is a limited one.

When an infectious disease has gained foothold in a herd the course
to be pursued in getting rid of it will depend upon the nature of the
malady. A good rule is to kill diseased animals, especially when the
disease is likely to run a chronic course, as in tuberculosis. The next
important step is to separate the well from the sick by placing the



INFECTIOUS DISEASES OF CATTLE. 375

former ou fresh ground. This is rarely possible, hence the destruction
or removal of the sick, with thorough disinfection of the infected local-
ity, is the next thing to be done. As to the disinfectants to be used,
special directions are given under the various diseases, to which the
reader is referred. Here we will simply call attention briefly to the
general subject.

Disinfection consists in the use of certain substances in solution which
destroy bacteria or their spores, or both. Those which are cheapest and
most available for animal diseases are ordinary freshly slaked lime or
unslaked in powder, chloride of lime, crude carbolic acid, and mercuric
chloride or corrosive sublimate.

(1) Slaked lime is perhaps the most easily procured, but its disin-
fecting power is limited. While it is capable of destroying all bacteria
in their vegetative state, it is unable to destroy spores such as those of
anthrax and black quarter. It is probable, however, that in incrust-
ing spores it may destroy their vitality sooner or later. It is regarded
as safe -practice to use only spore-destroying substances for the virus
of those diseases of which we have no definite knowledge. Neverthe-
less in the absence of other disinfectants lime is very useful. It may
be employed as a whitewash on wood and stone and sprinkled as a
dilute wasli or in powder over yards, manure heaps, and over carcasses
before they are buried and over the ground on which they have lain,
to prevent other animals from carrying the infection away.

(2) Chloride of lime is more efficient than simple slaked or unslaked
lime, since it destroys spores. It is the ordinary bleaching powder of
commerce, and is quite unstable, hence old preparations, unless sealed,
are of little value. A 5 per cent solution is sufficiently strong for all
spore-bearing bacteria (3 ounces in 2 quarts of water).

(3) Crude carbolic acid. The ordinary purified carbolic acid is too
expensive to be used on a large scale, and the crude product is a very
good substitute. This is made more powerful by mixing with it an
equal A'olnme of commercial sulphuric acid. While the sulphuric acid
is being added to the crude carbolic acid much heat is evolved, and if
the glass jar in which the two are mixed together is placed in cold
water the resulting product is said to hare a higher disinfecting power.
The mixture is added to enough water to make a 5 per cent solution
(almut 3 ounces to 2 quarts of water). This is strong enough for all
purposes. It may be kept in wood or glass but not in metal, owing to the
corroding action of the acid. It should be applied freely on woodwork
and on infected floors. It must be borne in mind that it may be inju-
rious to the hands, and to the feet of animals which arc compelled to
walk in it. In most cases where ita application becomes desirable
and this rule Hhould apply to all disinfections the disinfected stables,
stalls, etc., Hhould remain vacant as long as possible before cuttle are
again put in.

(4) Mercuric chloride or corrosive sublimate is a powerful disinfe.e-



376 DISEASES OF CATTLE.

tant but it is likewise very poisonous, hence its uses are limited. A
solution of one-tenth per cent is usually sufficient (1 ounce to 15 gallons
water). It is corrosive, and hence metal pails and dishes are to be
avoided. All solutions should be labeled "poison," and to avoid acci-
dents none should be kept on hand. In general the three first men-
tioned are safer, and Nos. 2 and 3 equally powerful in the solutions
recommended.

In addition to these artificial substances there are several natural
sanitary agents of great importance as destroyers of virus. These are
cleanliness, ventilation, drying, and sunshine. All virus excepting such
as may live in the soil is killed sooner or later by drying and sunshine,
and the importance of these factors in the daily life of animals need not be
insisted on here. Finally, all sanitary measures which contribute to the
healthfulness of animal surroundings are directly or indirectly inimical
to disease germs, and all carelessness in the keeping of animal s may b<J
regarded as an ally of these destructive organisms.

CONTAGIOUS DISEASES.

(Description of Plate XXIX.)

The bacteria on this plate are partly from tissues, partly from cultures, and stained
artificially with aniline colors (fuchsin or methylene blue). Figs. 6 and 7 are
copied from Friinkel and Pfeiffer's atlas. All but Fig. 7 are magnified 1,000 times;
Fig. 7, 500 times.

Fig. 1. Bacteria from pneumonia in cattle. These are also the cause of Wild-
seuche and Riuderseuche in Europe, and are closely related to swine-plague bacteria
These bacteria were drawn from a piece of spleen-pulp (rabbit).

Fig. 2. Micrococci (staphylococcus) which produce inflammation and suppuration,
also pyaemia.

Fig. 3. Micrococci (streptococcus) which produce inflammation of the liniug mem-
branes of the abdomen, thorax, heart, brain, and joints. Frequently associated
with the preceding bacteria in abscesses.

Fig. 4. Bacilli of black quarter. The pale oval bodies as well as the light spots
in cue end of the bacilli represent spores.

Fig. 5. Bacilli which produce tetanus or lockjaw. The light spot in the enlarged
ends of the rods represent a spore.

Fig. 6. Bacilli of tuberculosis. Microscopic sections of a pearly nodule from the
lining membrane of the chest cavity. The bacilli are stained red and appear as
small straight rods within the cells of the nodule or tubercle.

Fig. 7. Bacilli of anthrax. Bacilli from the spleen of a mouse inoculated with a
culture. The bacilli were obtained from the blood of a cow which died of anthrax
in Mississippi. The bacilli appear as rods stained blue. The round bodies are blood
corpuscles, also stained artificially.

CONTAGIOUS PLEURO -PNEUMONIA.

Definition and history. This disease has been eradicated from the
United States, and it is not probable that it will ever be seen in this
country again. As, however, much interest has been manifested in re-
gard to it for a number of years, and as our cattle are still prohibited
from some foreign markets on account of its recent existence here, the
subject is treated at greater length than would otherwise be necessary.



INFECTIOUS DISEASES OF CATTLE. 377

Thecontagiouspleuro-pneumoniaof cattle is a specific epizootic disease
which affects bovine animals, and from which other species are exempt.
It is characterized, when the disease results from exposure in the usual
manner, by an inflammation of the lungs and pleurae, which is generally
extensive, and which has a tendency to invade portions of these organs
not primarily affected, and to cause death of the diseased portion of the
lung. This disease is frequently called the Jung plague, which corre-
sponds with its German name of Lungenaeuche. In French it is spoken
of as the peripneunwnic contagicuse.

The history of the contagious pleuro-pueumonia of cattle can not be
traced with any certainty to a period earlier than the beginning of the
eighteenth century. 2fo doubt it existed and ravaged the herds of
Europe for many years and perhaps centuries before that time, but
veterinary knowledge was so limited that the descriptions of the symp-
toms and post-mortem appearances are too vague and too limited to
admit of the identification of the maladies to which they refer. It has
been supposed by some writers that certain passages in the writings of
Aristotle, Livy, and Virgil show the existence of pleuro-pneumonia at
the time that their works were composed, but their references are too
indefinite to be seriously accepted as indicating this rather than some
other disease.

As early as 1713 and 1714 it seems quite plain that pleuro-pneumonia
existed in Suabia and several cantons of Switzerland. Even clearer
accounts are in existence of its prevalence in Switzerland in 1732,
1743, and 1765. In 17G9 a disease of cattle was investigated in
Franche-Cointe by Bourgelat which was called murie, but which un-
doubtedly was identical with the pleuro-pueuinonia of to-day. From
that period we have frequent and well-authenticated accounts of its
existence in various parts of Europe. During the period from 1700 to
1812 it was pread throughout a large portion of the continent of
Europe by the cattle driven for the subsistence of the armies, which
marched and countermarched in all directions. It was generally prev-
alent in Italy in 1800. It appears to have been unknown, however, in
the department of the Nord, France, until 1820, but during the years
from 1820 to 1840 it penetrated into most parts of that country. Dur-
ing the same period it wan introduced into and allowed to spread over
Belgium and Holland.

This contagion is said to have been carried to Ireland from Holland
in 1839, and is reported as existing in Kngland in 1842. The disease
was brought to the United States at several different times. Probably
the first introduction of the contagion wa.s with a diseased cow sold
in Brooklyn, N. Y., in 1843. It came to New Jersey by importing
affected animals in 1847. Massachusetts was infected in the same
way in 1800.

South Africa was infected by a bull brought from Holhuul in 18T>4,



378 DISEASES OF CATTLE.

and Australia likewise received the contagion with an English cow in
1858. It is also reported as existing in various parts of the continent
of Asia, but the time of its first appearance and the extent of its dis-
tribution are very uncertain.

Some countries, which had only been infected for a short time, such
as Norway, Sweden, and Denmark, have succeeded in eradicating the
disease without much difficulty by slaughtering all affected and exposed
animals. Other countries long infected, and in which the contagion
was thoroughly established, like Australia, South Africa, Italy, France,
Belgium, and parts of Germany, have labored long, in some cases mak-
ing no progress, and in others being only partially successful. Holland
was one of the first of the thoroughly infected countries to free itself
from the contagion.

In the United States, Massachusetts eradicated pleuro-pneumonia
during the period from 1860 to 1866. New York and New Jersey made
an attempt to eradicate it in 1879, but were not successful. Late in
1883 the contagion was carried to Ohio, probably by Jersey cattle pur-
chased in the vicinity of Baltimore, Md., to which place it had extended
previous to 1868. From the herd then infected it was spread by the
sale of cattle during 1884 to a limited number of herds in Illinois, to
one herd in Missouri, and to two herds in Kentucky. The alarm caused
among the stock-owners of the United States by this widespread dis-
semination of a disease so much dreaded led to the adoption of active
measures for its control and eradication. By cooperation between the
United States Department of Agriculture and the authorities of the
affected States it" was found possible to prevent the further spread of
the contagion and to eradicate it after a few months' delay.

In 1886 pleuro-pneumonia was discovered in some of the large dis-
tillery stables of Chicago, and among cows on neighboring lots. This
led to renewed efforts to secure the complete extirpation of this disease
from the country. Congress, in 1887, enlarged the appropriation avail-
able for this purpose, and gave more extended authority. During the
same year the disease was stamped out of Chicago, and has not since
appeared in any district west of the Allegheny Mountains.

The work of eradication was at the same time commenced in all of
the infected States. Before the end of the year 1889 Pennsylvania,
Delaware, Maryland, the District of Columbia, and Virginia had been
freed from the disease. More difficulties, however, were encountered
in the States of New York and New Jersey, on account of the larger
territory infected and the density of the population. The long strug-
gle was crowned with success, however, and the last animal in which
the disease appeared in the State of New York was slaughtered early
in 1891, and the last one affected in New Jersey met the same fate early
in the spring of 1892.

During these same years a supreme effort has been made to stamp
out this lung plague from Great Britain. From the official reports it



IM.ATK XXIX



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WHICH iM/nnrcK IMSKASH IN'CATTLK



INFECTIOUS DISEASES OF CATTLE. 379

s

appears that the number of infected districts and of diseased animals
have rapidly diminished, and there is good reason to believe that if the
work is continued for a sufficient time it will meet with success. The
chief obstacle appears to be in connection with Ireland, where the con-
tagion is believed to be widely disseminated and where the activity of
the authorities is not so manifest as in England and Scotland. If the
contagion is allowed to linger in Ireland it is very plain that Great
Britain can never long remain free from it.

The other infected European countries, though they maintain a vet-
erinary sanitary service, are not making satisfactory progress in eradi-
cating the disease. This is due partly to delays in carrying out the
provisions of the laws and partly to mistaken ideas as to the measures
which are necessary to accomplish the object. The United States was
the last of the countries, having old infected districts, which undertook
to stamp out this contagion, and, excepting Holland, it is the first to
reach success.

The cause (etiology) of pleuro-pnenmonia. This is a contagious dis-
ease, and on the American continent, at least, it only arises by contagion
from a previously affected animal. It is, consequently, never seen here
except as the result of importing affected animals from the Old World.
When thoroughly stamped out it does not reappear, and if imported
animals continue to be properly inspected and quarantined we have
every reason to believe that pleuro-pneumonia will never again be seen
affecting the cattle of this country.

The exact nature of the virus or contagion of lung plague has never
been determined. Efforts have been made by the methods now common
in bacteriology to cultivate and isolate the pathogenic germs, but up
to the present these have not been successful. Various investigators
have from time to time claimed the discovery of the specific germs of
the disease, but in every case these claims have proved to be unfounded*
The methods now in use for such investigations do not appear proper
for the discovery of these germs. They do not multiply in any of the
substances which are used to cultivate other disease germs, and they
are not revealed by the most advanced methods of microscopical
research. That this disease is caused by microorganisms of some kind
appears certain from our knowledge of the cause of other contagion*



Online LibraryUnited States. Bureau of Animal IndustrySpecial report on diseases of cattle and on cattle feeding → online text (page 43 of 56)