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 UNIVERSITY OF ILLINOIS

 Agricultural Experiment Station




 BULLETIN NO. 152




 CONTAGIOUS ABORTION OF COWS

 BY W. J. MACNEAL IN COÖPERATION WITH HERBERT W. MUMFORD




 [Illustration]




 URBANA, ILLINOIS, NOVEMBER, 1911




SUMMARY OF BULLETIN NO. 152


1. The existence of a specific contagious disease causing abortion in
cows has been recognized for a long time, and it is certain that the
disease known abroad as infectious or contagious abortion is also
prevalent in the United States.

2. The infectious agent is a bacterium first described by the Danish
investigators, Bang and Stribolt. This microörganism has been isolated
from aborting cows in various European countries and in the United
States.

3. Bacteriological examination of afterbirths from aborting cows at this
Station revealed the presence of this germ.

4. To eradicate the disease from a herd, the affected cows should be
isolated, and their genital passages cleansed once or twice daily with
an antiseptic solution until all discharge has ceased, when they may be
returned to the herd; all infectious material (afterbirth and
discharges) should be burned; infected stalls should be cleaned and
disinfected; the sheath of the herd bull should be cleansed with a
disinfectant solution before and after service, and a separate, clean
bull should be used for heifers and clean cows.




CONTAGIOUS ABORTION OF COWS

BY W. J. MACNEAL, ASSISTANT CHIEF IN BACTERIOLOGY, IN COÖPERATION
WITH HERBERT W. MUMFORD, CHIEF IN ANIMAL HUSBANDRY




INTRODUCTION


The premature discharge of the products of conception from the uterus is
a not infrequent occurrence among domestic animals, and doubtless
various factors may from time to time operate in its causation. For a
long time, however, practical husbandmen have recognized an epizoötic or
contagious kind of abortion, a definite transmissible disease in which
the loss of the fetus is the most prominent characteristic. The
transmissibility of contagious abortion of cows appears to have been
demonstrated experimentally for the first time by Brauer. Experimental
transmission has been performed by a number of investigators
subsequently, the work of Nocard (1886) furnishing conclusive evidence
upon this point.

It is certain that a disease, or possibly more than one disease, of this
nature is a source of serious loss to the live stock industry in the
United States, and there can no longer be any doubt that a considerable
part of this loss is due to the definite specific disease prevalent on
the continent of Europe and in England, and known as Contagious,
Infectious, or Epizoötic Abortion. The purpose of this bulletin is the
brief presentation of some of the facts concerning the cause, prevention
and restriction of this disease, which have been established by modern
investigation, for the information of men engaged in live stock
production.


BACTERIOLOGICAL INVESTIGATIONS ELSEWHERE

Nocard carried out the first extensive bacteriological investigation of
contagious abortion. In microscopic preparations of the diseased
placenta he was able to recognize numerous short bacilli and micrococci.
These were also found in the amniotic fluid. He obtained pure cultures
of these two organisms, but failed to induce abortion upon inoculating
these cultures into other animals. Neither of the germs obtained in
culture could therefore be regarded as the causative agent in the
disease.

In 1895 Bang and Stribolt undertook the investigation of this disease,
and their results are now generally regarded as the most important of
all the contributions to the study of this subject. A cow showing all
the symptoms of impending abortion was purchased and slaughtered. The
unopened uterus was removed to the laboratory where it was opened with
special precautions to avoid all contamination. An abundant, grayish
yellow, odorless exudate was found between the ovum and the inner wall
of the uterus. Upon standing this exudate separated into two layers, a
reddish yellow serum above, and a grayish yellow partly solid layer
below. In microscopic preparations of this exudate, stained with
Loeffler's methylene blue, numerous very small bacilli were found,
apparently in pure culture, some of them lying free, but large numbers
of them crowded together inside cells. These latter appeared at first to
be micrococci, but more careful examination proved them to be really
short rods. Bang and Stribolt were able to cultivate this organism in
tubes of a gelatin-agar-serum medium, the germ developing only in a
particular zone beginning about 5 mm. beneath the surface of the medium
and extending downward 10 to 15 mm. After considerable work with
cultures, they concluded that the bacillus is neither an aerobe nor an
anaerobe, in the ordinary sense, but exhibits a very peculiar behavior
in respect to oxygen, requiring for its development a partial pressure
of oxygen somewhat less than that present in the atmosphere. They were
unable to obtain growth of the germ in the presence of the ordinary
atmosphere, nor in the absence of oxygen (Pyrogallol method). Curiously
enough, by placing their tube cultures in an atmosphere of pure oxygen,
they obtained cultures developing in two zones, one near the top and the
other near the bottom of the tube, indicating that there are two optima
in the oxygen requirement of the organism. This very interesting
character of the organism received great attention at their hands, but
nevertheless Bang points out that typical development such as he has
pictured was not always obtained, a number of factors seeming to cause
variation in the position and extent of the developmental zones in these
tube cultures. By exhausting the air above the medium in the tube, the
growth was made to extend to the surface. In this way they were able to
obtain growth of the bacillus on plates, but they did not work out a
reliable plate method, preferring to employ the dilution tube cultures
for separation in all their work. Bang and Stribolt subsequently
examined pieces of placenta from a large number of cases of contagious
abortion, and found the bacillus microscopically in practically all
cases. Sometimes they were abundant, in other instances very scarce.
Most of this material was badly contaminated, yet, from that sent in
during the colder season they successfully isolated the bacillus in pure
culture in a majority of the cases. In three fetuses the bacillus was
found in the intestinal contents in pure culture; in one fetus it was
isolated from the blood. Two cows with mummified fetus _in utero_ were
examined _post mortem_. These fetuses had been dead 9 months and 5
months respectively but the surrounding exudate still contained the
abortion bacillus and pure cultures of it were obtained from each case.
Uterine exudate kept in the refrigerator still contained living abortion
bacilli after seven months.

Having found the same bacillus microscopically in a series of cases of
abortion, and having obtained it in pure culture from a number of them,
it now remained for Bang and Stribolt to produce the disease by
inoculation of these cultures into healthy animals. Four pregnant cows
were obtained without knowledge of their previous history. Two of them
were inoculated by intravaginal application of pure cultures, and two by
intravaginal application of pieces of afterbirth from aborting cows. No
abortion resulted in any of the cows and at slaughter 19 to 29 days
after inoculation, there was no evidence of the disease. This result was
surprising, as Brauer had induced abortion by the second of the
above-mentioned procedures in from 9 to 21 days, Lehnert in from 12 to
20 days, and Trinchera in 9 to 13 days. The authors thought that the
animals may have been immune on account of a previous attack of the
disease, or that possibly the interval between innoculation and
slaughter (19 to 29 days) may have been too brief for the disease to
have developed. For the next experiment two cows were purchased from a
region where abortion was unknown. Pregnancy began January 14 and
January 16, 1896. On April 14, a rich culture of the abortion bacillus
was injected well up into the anterior end of the vaginal canal of each
of these cows. The inoculation was repeated in the same way on May 23,
and again on June 4. One cow aborted June 24, the fetus evidently having
been dead some days. The abortion bacillus was isolated from the
afterbirth. The other cow showed the signs of impending abortion on June
23, and was slaughtered on June 24. The condition inside the uterus
resembled in every respect that observed in the cow from which the
original culture had been isolated, and the bacillus was present in pure
culture. In these cows the disease had appeared 10 weeks after the first
inoculation. A third cow was inoculated by intravaginal application
January 19, 1897, and subcutaneously March 6, in both instances with
pure cultures of the bacillus. Premature delivery of a living calf
occurred April 9, 80 days after the first inoculation. Abortion was also
caused in sheep by intravaginal application and by intravenous injection
of pure cultures. Inoculation by the latter method proved to be more
certain in these animals, and the incubation period after intravenous
injection was only 7 days in one case and 12 days in another.
Intravenous inoculation of a mare resulted in a premature delivery after
28 days. In all these cases the bacillus was recovered from the
afterbirth.

In 1902, Preisz at Budapest isolated the same bacillus from two cases of
contagious abortion in cows. He confirmed the findings of Bang in
respect to the oxygen requirements of the organism, and was able to
obtain cultures by a variety of methods on ordinary media. Apparently
his cultures were less vigorous than those of Bang, for they soon died
out, their resistance to germicides was slight, and all his
inoculations into animals, including two pregnant cows, two pregnant
guinea pigs, and one pregnant rabbit, as well as a number of other small
animals, were without positive result. Preisz named the organism
"_Corynebacterium abortus endemici (s. infectiosi)_."

In 1908, Nowak at the University of Krakau in Austria made a very
important contribution to the study of this disease. He found the
culture method of Bang and Stribolt very useful for the identification
of the organism when obtainable in pure culture, and when the
contaminating bacteria were few in number. When other bacteria were
numerous, as is frequently the case in material obtained for
examination, he found this method difficult. The pyrogallol method of
Preisz also proved to be unreliable in his hands. Eventually he devised
a method of plate culture which proved to be very useful. Ordinary agar
was melted and cooled to 50° C. then mixed with about one fourth its
volume of naturally sterile blood serum, and poured into sterile Petri
dishes where it was allowed to solidify. The piece of placenta or other
material to be examined was then streaked over several of these plates
in succession, and the plates were incubated for 24 hours at 37° C., to
allow contaminating bacteria to develop. The plates were next placed in
a glass jar together with a culture of _Bacillus subtilis_, one square
centimeter of culture surface of the latter organism being provided for
each 15 cc. capacity of the jar. The jar was sealed and placed at 37° C.
for three days, at the end of which time excellent surface colonies of
Bang's bacillus were obtained. By the application of this method Nowak
has succeeded in isolating the bacillus from the blood and intestinal
contents of a number of fetuses, and from uterine discharge, when other
methods failed. He has also observed that one could gradually decrease
the amount of culture surface of _B. subtilis_ employed in succeeding
cultures and eventually get the bacillus of Bang to grow in the presence
of atmospheric air, altho the cultures were relatively poor ones. Nowak
also confirmed Bang by obtaining cultures in an atmosphere of nearly
pure oxygen, as well as in ordinary air under a pressure of three
atmospheres. His cultures were evidently vigorous for some of them were
successfully transplanted after two years. Nowak used ordinary agar as a
medium with considerable success, and found glucose agar to be almost as
favorable to the growth of the bacillus. For the detection of the germ
in pathological material, however, these media proved to be inferior to
the serum-agar mixture in several cases. Cultures were obtained in broth
and in milk without coagulation, contrary to the statement of Preisz. No
gas was produced in sugar broth. Nowak inoculated a number of pregnant
laboratory animals, and produced abortion with great regularity in
guinea pigs and rabbits by subcutaneous, intravenous and intraperitoneal
injection. He did not succeed in producing abortion by intravaginal
application nor by feeding. No tests were made upon larger animals much
to his regret, as in his opinion the experiments of Bang upon cows still
left something to be desired in the way of experimental evidence.

McFadyean and Stockman (1909) have investigated the contagious abortion
of cattle in Great Britain, and have found it to be identical with that
studied by Bang in Denmark. They were able to produce the disease in
cows by intravenous injection of natural virus and of active pure
cultures, without a failure in eight experiments. By intravaginal
application they caused the disease twice with cultures and three times
with natural virus, but also failed to obtain any result in three trials
with the natural virus. Subcutaneous inoculation was successful three
times in five trials. By feeding they produced the disease three times
in four trials. These authors consider ingestion to be an important mode
of contracting contagious abortion in nature.

Zwick (1910) has made a preliminary report of the bacteriological
investigation of contagious abortion at the German Imperial Health
Office. By a comparative study of cultures, the unity of the disease in
Denmark, Germany, England, and Holland has been established. Certain
individual differences were detected in the various culture strains
examined, and it was found that the bacillus could be readily cultivated
upon various ordinary laboratory media, and that it could also adapt
itself to an aerobic existence, thus confirming the work of Nowak. In
one instance the bacillus grew aerobically immediately upon isolation
from the animal body. Abortion was induced in sheep, goats, and rabbits
by intravenous injection, intravaginal application, and also by feeding.
Work upon the use of abortin (analogous to tuberculin) for diagnosis,
and upon the agglutination and complement fixation tests, was in
progress at the time the report was made.


BACTERIOLOGICAL OBSERVATIONS AND EXPERIMENTS AT THIS STATION

In the United States contagious abortion is widespread, and has been
recognized for a number of years by practical husbandmen as an important
economic factor in animal industry. Epidemiological studies have
recently been reported from Arizona and Connecticut. At the Illinois
Agricultural Experiment Station the beef cattle herd has suffered
considerable loss from abortion for several years past, and the presence
of contagious abortion had been recognized by Professor Mumford, altho
this diagnosis was disputed by other authorities. In order to settle the
question it seemed best to undertake a bacteriological study of the
disease. This seemed the more desirable because, so far as we have
ascertained, there was no known microörganism generally recognized and
accepted as the cause of the disease in this country, the bacillus
described by Bang having been found only in Europe and his work having
failed to be confirmed by American investigators.

Altogether eighteen parturient cows have been examined
bacteriologically. Ten of these calved at term and the births appeared
to be normal. The abortion bacillus was not found in any of these. Eight
were cases of premature delivery, and of these, six appeared clinically
to be cases of contagious abortion. Placental tissue from two of these
cases was examined by the Nowak plate method and a bacillus isolated,
apparently identical with that isolated by Bang in Denmark and by Nowak
in Austria.

The organism is a very small short rod, usually oval in shape, from 0.8µ
to 2.0µ long by 0.7µ wide, practically always single, rarely in short
threads of two to four cells. It is not motile, and does not form
spores. It stains with moderate rapidity with the ordinary anilin dyes,
and is decolorized by Gram's method. The colonies on serum-agar are
raised, with smooth circular borders, appearing almost like drops of
dew. They are transparent and very clear, with a bluish gray color by
transmitted light. Under the microscope a few coarse granules may be
seen near the center of the colony but the greater part of it appears
very homogenous and almost water-clear. The appearance of the colony is
really a very characteristic feature of the organism and enables one to
distinguish readily the colony of the abortion bacillus from other
colonies on the serum-agar plates.

The behavior toward oxygen is another character upon which considerable
reliance may be placed in the identification of strains recently
isolated from the animal body. This is tested by transplanting the
colonies from the serum-agar plates to two series of agar streak
sub-cultures, of which one series is incubated in the atmospheric air
and the other in the closed jar together with cultures of _B. subtilis_.
Unless the growth under the latter condition is much better than the
growth outside the jar, the culture may be discarded as one not
belonging to this species.

A final important test in identification is that of pathogenicity. Nowak
induced abortion in pregnant guinea pigs with great regularity by
subcutaneous, intraperitoneal, and intravenous injection of pure
cultures of the abortion bacillus. So far, four pregnant guinea pigs
have been inoculated subcutaneously with the pure cultures isolated by
us, and the inoculation has been followed by premature evacuation of the
uterus with death of the fetuses in 3-½ 8, 6, and 7 days
respectively. In the first guinea pig the two fetuses were practically
fully developed and covered with hair. In this instance the abortion
bacillus was isolated only from the subcutaneous tissue of the mother
at the point of inoculation, the cultures from the uterus, the placenta,
and the fetuses remaining negative. In the other three cases the fetuses
were undeveloped and the condition was that of a true abortion. In these
instances the abortion bacillus was demonstrated by culture tests at the
point of inoculation in pure culture in two, in mixed culture in the
other one; in the interior of the uterus in pure culture in all three;
in each of the four placentæ of two cases in mixed culture, as these
placentæ had been passed some time before they were found, and in the
three placentæ of the other case in pure culture; in the livers of all
three fetuses of the one case in pure culture, but not in the other four
fetuses; in the heart blood of the mother in pure culture in one case,
but not in the other two cases. In all these tests the mother guinea pig
was killed by chloroform soon after the abortion had occurred.

From the results of these tests we have concluded that the bacillus
isolated by us from aborting cows is identical with that isolated by
Bang and by Nowak. Further, the investigations of Bang, Preisz, Nowak,
McFadyean and Stockman, and Zwick, seem to justify the acceptance of
this organism as the infectious agent in the contagious abortion of
cattle.

The principles of bacteriological nomenclature have not as yet been
universally adopted, and most of the investigators quoted in this paper
have avoided the use of a specific name for the abortion bacillus. Bang
himself seems not to have given it a binomial designation, but he
repeatedly employed the term "Abortusbacillus" as a specific term.
Chester (1901) has named the organism "_Bacterium abortivum_" with the
synonym "Bacillus of contagious abortion in cows, Bang." Preisz (1902)
suggested the name "_Corynebacterium abortus endemici (s.
infectiousi)_." This generic name Corynebacterium appears to be
incorrect, as the organism is very different from those to which this
name has been previously applied. It would seem best to employ the more
general term Bacillus (or Bacterium) as a confessedly temporary generic
name until a more definite generic nomenclature of bacteria shall have
been developed and generally adopted. In determining the specific name
it would seem that the term "Abortusbacillus" employed by its
discoverer as early as 1907 should receive first consideration. We[1]
have therefore suggested the name _Bacillus_ (or _Bacterium_)
_abortus_, Bang, for this organism. The term "_abortus_," being in the
genitive case, may be employed with either generic term.

FOOTNOTE:

[Footnote 1: MacNeal and Kerr, 1910.]


RESTRICTION AND ERADICATION OF THE DISEASE

Reliable methods for restricting the spread of contagious abortion and
for eradicating it from a herd may be expected as the result of more
complete and accurate knowledge of the nature of the disease and its
mode of spread. Some of these methods, such as that of artificial
immunization, are being tested experimentally by the Departmental
Committee appointed by the British Board of Agriculture and Fisheries to
inquire into Epizoötic Abortion. Until these methods have been developed
beyond the experimental stage, the older more or less empirical methods
will have to be relied upon. Fortunately these older methods can now be
subjected to careful scrutiny in the light of modern knowledge of the
disease, and they have been studied in this way by the British Committee
mentioned above. The following summary has been copied, with only slight
abridgment and very few alterations, from the report of this Committee.

"The methods which have been relied upon in the past for the prevention
of abortion and its eradication from a herd are:--

(1) Periodical spraying of the external genital organs and hind quarters
with disinfectant solutions.

(2) Isolation of animals as soon as they show the premonitory signs of
abortion.

(3) Internal administration of carbolic acid to animals supposed to be
infected or exposed to infection.

(4) Irrigation of the genital organs of animals which have aborted with
antiseptic solutions.

(5) Removal and disposal of animals which have aborted.

(6) The keeping of a special bull for serving animals which have
aborted, or, what is based on the same idea, the disinfection of the
external genital organs of the bull with antiseptic solutions after he
has served such a cow.

(7) Destruction of the abortion membranes, and disinfection of the parts
of the buildings, litter, etc., with which the infective material has
come in contact.

(8) The keeping of a goat, especially a male goat, in a byre with the
cows."

It cannot be said of the above measures that either singly or
collectively they have brought about any material improvement in the
general condition of our herds in relation to abortion. According to
reports, decided improvements have been effected in individual herds by
the adoption of isolation and disinfection, while in others very little
has been accomplished. Some of the above methods are founded on nothing
more than ignorant empiricism, while others are based upon pathological
and physiological considerations which are only partially correct in
their applications. Since most of them have obtained a certain amount of
hold, at least on the minds of stockowners, it may be useful to discuss
each measure separately in the light of our recent investigations.

_Spraying of the External Genital Organs._--This is a procedure which
probably has little or no value. (_Abridged._)

_Isolation of Animals as soon as they show Signs of Abortion._--The
necessity for this measure is obvious, and its importance cannot be too
much insisted on. An infected animal only becomes infective to others
immediately before the act of abortion, and may remain so for some weeks
afterwards. However, only a proportion of the affected animals show
premonitory signs, and quite a number may abort amongst their companions
without warning. Under such conditions, then, measures of immediate
isolation lose much of their undoubted theoretical value, owing to the
difficulty in the way of carrying them out in practice. There is not
likely to be any serious difficulty in diagnosing the bacterial disease
after an act of abortion, even in an isolated case, if the membranes are
available in a reasonably fresh state. (_Abridged._)

Isolation of the affected animals, however, must be complete before and
after the act to be of any real value. Having regard to what appears to
be the most common form of infection, viz., by ingestion, we do not
think that anything material is to be gained by merely putting all the
cows about to abort and those which have aborted at the lower end of a
byre, so that the infective discharges may not come in contact with the
external genital organs of their fellows, unless we assume that
infection frequently takes place by an animal licking virulent material
from a part of its body where it has been deposited by flicks of the
tail which has been contaminated by lying in the gutter behind the
stalls.

_Internal Administration of Carbolic Acid._--The uselessness of carbolic
acid and other antiseptics as curative agents has already been referred
to. As a preventive agent by internal administration we believe carbolic
acid to be equally useless. Even if it were possible to administer very
large doses of this poisonous substance, one could not expect to be able
to give enough to destroy the bacilli which have been swallowed and
mixed with the contents of the enormous stomachs and intestines, and it
would be equally hopeless to expect to destroy in this way the bacilli
which have already reached the womb. This alleged measure of prevention
must be regarded as an absurdity which has gained a certain amount of
support owing to observations carelessly collated and carelessly
interpreted.

_Irrigation of the Genital Passages after Abortion._--With the act of
abortion the greater part of the uterine exudate is immediately ejected.
That some of it remains behind for a short period is certain, since we
were able to demonstrate abortion bacilli in material obtained from the
vagina of a heifer three days after she had aborted. On the other hand,
no abortion bacilli could be found in the uterus of another heifer a
month after she had aborted. It seems probable that, as a rule, the
genital organs cleanse themselves by natural means a comparatively short
time after abortion has taken place. Almost immediately after abortion
and expulsion of the membranes the uterus contracts, and its internal
surfaces come into apposition. Its condition is such that it would not
be possible to force fluid into it with a pump from the vagina. Apart
then, from the probability that disinfection of the uterus by
antiseptics is not necessary to rid the organ of abortion bacilli, we
are of opinion that it is futile to attempt it by irrigation methods. So
long as a discharge continues to come from the genital passages, we
think that for hygienic and therapeutic reasons they ought to be
cleansed once or twice by the intravaginal injection of tepid antiseptic
solutions, such as a 2 per cent solution of carbolic acid or a 1 in
3,000 solution of corrosive sublimate, but not on the ground that the
injections will disinfect the uterus. We are of opinion that it will
seldom be necessary to continue the injections for more than a month,
and that after three months there should be small risk in putting the
cow to the bull, provided she is afterwards protected from fresh
infection.

_Removal and disposal of Animals which have aborted._--It is quite a
prevalent custom to feed for the butcher cows which have aborted. It is
also customary to sell such cows alive in the open market. The second
custom we consider likely to introduce disease to other establishments,
unless the animals have ceased to discharge; they should, we think, be
kept for at least three months after abortion before being sent for
sale.

The first custom is less objectionable than the second, but we think
that a breeder will be more likely to get rid of abortion from his herds
by keeping such animals than by disposing of them and bringing in new
ones before his entire herd is free from the disease. There can be no
doubt that in most cases an attack of the disease greatly increases an
animal's resistance to future attacks, and that in a large proportion of
the affected, probably in the majority, this resistance is sufficient to
fortify them against infection during their next pregnancy. It is beyond
doubt that a considerable proportion may abort twice in succession, but
it is not improbable that inoculation methods may now be successfully
employed to exalt their resistance. In the midst of infection there is
no better guarantee against the disease than the possession of an immune
stock, and for this reason we consider that on infected premises the
animals which have already aborted are to be looked upon as valuable
assets for purposes of eradication, much more valuable than the new and
susceptible animals brought in. We find, however, that a small
proportion of cows will not hold to the bull for an indefinite period
after abortion, and it may be found better to fatten off such animals,
unless they are of high value.

_The Keeping of a Special Bull for Cows which have aborted._--We have
already stated that we do not consider the bull a factor of the first
importance in the dissemination of abortion but that infection by means
of a contaminated bull must be looked upon as a distinct possibility. We
think, therefore, that there is something to be said in favor of keeping
a bull for the service of cows which have aborted, and, when that is not
possible, of disinfecting the external genital organs of the bull after
he has served such cows. Of course, if the cows can be immunized the
same bull might be used for all. We do not think that cows from a clean
establishment should be sent even to a clean bull on infected premises,
and it is also inadvisable that cows from infected premises should be
sent to a bull on a clean establishment.

_Destruction of Virulent Material and disinfection of everything
contaminated by it._--The immediate disinfection of the virulent
materials and contaminated objects is of great importance, more
especially as it appears that the natural virus may remain active for a
long time outside the body. The soiled litter, dung, exudate, membranes,
and fetus should all be removed at once, preferably after they have been
treated with caustic lime. After removal they should be soaked in
paraffin and burned, or buried in a deep pit, preferably the former. On
no account should the fetus and membranes be fed to pigs or dogs. When a
fetus is aborted alive, as sometimes happens, it seldom survives long,
and it is advisable to kill and destroy it, since it may excrete
abundance of virulent material from its intestines if allowed to live.
If, however, it be decided not to kill it, it should immediately be
isolated. The walls of the stall and the floor should be washed or
strewn thickly with caustic lime, or drenched freely with boiling water.
The temperature necessary to kill the bacillus is not great, and this
simple method of disinfection should prove efficacious. Lastly, the
boots, clothing, and hands of attendants should be disinfected by making
use of any reliable disinfectant, such as 3 or 4 per cent solution of
carbolic acid.

_The keeping of a Goat amongst the Cows._--This, we believe can only
have had its origin in ignorant superstition, but we feel bound to
mention it, as the question of its efficacy has quite frequently been
seriously put to us. We would point out that goats themselves can be
infected with cattle abortion, and that both male and female goats were
on our premises during the greater part of the time occupied with the
cattle experiments, and their presence did not prevent animals from
aborting.

_Preventive Inoculation._--This is still in the experimental stage and
definite results are hoped for. (_Abridged._)

The Committee refrained from making any recommendations in regard to
measures to be taken by the Board of Agriculture and Fisheries for the
prevention of the disease.

Experience in connection with the beef cattle herd at the Illinois
Agricultural Experiment Station with the methods of isolation, careful
disposal of infected material, cleaning and disinfection of infected
stalls, antiseptic irrigation of the genital passages of cows which had
aborted, and antiseptic irrigation of the bull before and after service,
together with the use of a special bull for heifers and clean cows, has
been very satisfactory. These measures were applied under the direction
of Professor H. W. Mumford and Mr. H. O. Allison. During the year
previous to the inauguration of these measures a large percentage of the
calves were lost by abortion. A decided improvement in respect to the
number of calves saved was coincident with the use of the procedures
mentioned above. They were applied to each case of abortion as it
occurred, until in the course of two years abortions have become very
infrequent and the herd is now considered free from the disease. It
should be noted, however, that those cows which had aborted were not
necessarily disposed of, but after local irrigation treatment until the
discharge had ceased, they were bred again. Some of the improvement in
the herd has, therefore, doubtless been due merely to the retention of
relatively immune cows.

Altho the experience here has been rather fortunate and the results
obtained seem to bear some relation to the employment of the measures
deemed worthy by the British Committee, we hesitate to state that there
was any necessary relation between them, because cattle men have
observed somewhat similar improvement in herds without the use of any
treatment at all. In other words, there appears to be a tendency for the
disease sometimes to die out in a herd or to become quiescent for a year
or two. On the other hand, the recommendations of the British Committee
supported as they seem to be by our local experience, certainly warrant
the recommendation of these measures for use in combating contagious
abortion. In any event good results cannot be expected without
intelligent, careful, and painstaking work, and it may be that some of
the failures in applying these measures have resulted from lack of
efficiency in applying them rather than from insufficiency of the
measures themselves.




References

1. =Bang.= Die Aetiologie des seuchenhaften ("infectiösen") Verwertens.
Ztschr. f. Thiermed. 1: 241-278. 1897.

2. =Board of Agriculture and Fisheries= (Great Britain). Report of the
Departmental Committee to inquire into Epizoötic Abortion. Part 1.
Epizoötic Abortion in Cattle. London, 1909.

3. =Chester.= A Manual of Determinative Bacteriology. 1901.

4. =McFadyean and Stockman.= Epizoötic Abortion. Report. Dept. Com. Bd.
Agr. and Fisheries. (Gt. Brit.), Appendix to Part I, 1909. Review in
Expt. Sta. Record =22=: 584-586. 1910.

5. =MacNeal= and =Kerr=. Bacillus abortus of Bang, the cause of
contagious abortion in cattle. Jour. Infect. Diseases =7=: 469-475
(1910).

6. =Nocard,= Review by =Bang=. Ztschr. f. Thiermed, =1=: 243-246. 1897.

7. =Nowak.= Le bacille de Bang et sa biologie. Annales de l'Institut
Pasteur =22=: 541-546. 1908.

8. =Preisz.= Der Bacillus des seuchenhaften Verwerfens. Centralbl. f.
Bakt. etc., I Abt. Orig. =33=: 190-196 (1903).

9. =Zwick.= Ueber den Erreger des infectiösen Abortus des Rindes.
Centralbl. f. Bakt. etc., Beilage zu I Abt. Ref. =47=: 219-220. 1910.


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End of Project Gutenberg's Contagious Abortion of Cows, by Ward J. MacNeal