This follows the same general course as does the disease in cows. In
certain American outbreaks (Kilborne and Th. Smith) it has been traced
to a bacillus like the colon bacillus, propagated in the womb and
genital passages, and which produced suppurating vaginal catarrh in cows
and mares on which it was inoculated. It is liable to occur, without
premonitory symptoms having been observed, and to be followed by no
marked sequelæ, so that, as in most cases in the cow, it may be looked
on as a purely local infection. In England, Penberthy, found it to occur
not earlier than the fourth month of gestation, yet he adduces several
cases in which the first case in a breeding stud occurred in four weeks
after the introduction of an infected mare from an aborting stud. In
America on large breeding farms the introduction of the infection has
proved ruinous, as many as 70 or 80 per cent. of the mares having
aborted in the same season.
The conclusion is inevitable, that as in the case of cattle, the sire
may become the means of transmission, and that the same measures of
prevention are demanded. The fact that the affection is less widely
spread or injurious, than in cattle, is largely due to the usual
presence of but one, two or three breeding mares on a farm, so that
there is little opportunity for a rapid extension of the infection.
Multiply and encrease our studs of breeding horses, as cows have been in
our dairying districts, and abortion, once introduced, would prove
equally infective, spreading and injurious.
_Therapeutics_ are useless in contagious abortion as the disease usually
runs its course before any danger is suspected. If premonitory symptoms
are observed, the abortion may sometimes be warded off for a time by
secluding the animal in a quiet place and seeking to obviate labor pains
by opiates and ounce doses of viburnum prunifolium.
_Prevention._ This is to be sought along two principal lines: 1st. The
protection of a sound herd against the infection: and 2nd. The
extinction of infection in a herd already diseased.
_Protection of a sound herd._ This requires the greatest possible care,
because the infected animal usually presents the general appearance of
perfect health, and there is no ready means of testing the presence or
absence of the abortion bacillus. In purchasing a cow or mare in a
public market the new owner may find her affected with this bacillus,
and a serious danger to his whole herd. To protect the latter he must
learn that the herd from which she came has had no abortions for several
years before, and that the offspring for the different years are present
in numbers corresponding to the dams. In the absence of this a
certificate, and guarantee against infection of other animals by the one
purchased, may well be demanded of the seller. A certificate from the
veterinarian attending the herd furnishing the animal, may also be
sought as evidence of the absence of abortion from the locality.
Imported animals should be safeguarded in the same way but with even
greater care, lest the microbian sources of new types of abortion,
should be brought into the country. A guarantee of this kind might well
be demanded by the Federal Government in the case of all breeding
animals imported.
In case of failure to secure the most perfect guarantee with the
purchased animal it would be worth the purchaser’s while to seclude it
from his valuable herd, and not to breed it with the other animals of
his herd until it has been proved to be entirely free from infection. If
bought for a sire it should be subjected to a course of disinfection of
the sheath and penis: if for a dam and unimpregnated, antiseptic
irrigation of the vagina may be made daily for a week, and the external
parts, hips and tail daily washed with antiseptics. If very important to
have her bred, secure, if possible, a male that is not to be used on
other animals. If this is impracticable, let the sheath and penis, and
surrounding skin be thoroughly disinfected as soon as the service has
been had.
If the newly acquired female is pregnant, keep her by herself until
parturition and, even if this takes place at full term, irrigate the
womb daily for a week with a disinfectant, delay having her served for a
month, and if she must go to the sire of the herd, subject him to
thorough disinfection after service. It may be that she still carries
the germ but has become tolerant of it.
_Extinction of Contagious Abortion in a Herd._ 1. Two separate stables,
or compartments, not having a common gutter should be provided, one for
the sound animals, and one for those that are known to be affected, or
that are open to suspicion.
2. The cow or mare that shows symptoms of abortion, or that has aborted,
should at once be removed to the quarantine stable, and her stall,
including the gutter and drain leading from it thoroughly disinfected.
The whole stable should be whitewashed.
3. The aborted fœtus with its membranes, should be at once removed and
burned, or boiled, or deeply buried after it has been thickly sprinkled
with chloride of lime or other active disinfectant.
4. The manure from the infected stable should be taken into an enclosure
into which no animals have access, and freely watered with a solution of
sulphate of copper (6:100).
5. All in the quarantined stable and even those left in the general
stable, should have the external generative organs, the hips, and the
whole length of the tail washed once or twice a day with an antiseptic
solution. Carbolic acid or creolin (2 or 3:100) makes a very safe and
convenient agent, but copper sulphate (6:100) or mercuric chloride
(2:1000) may be substituted. The colorless mercuric solution though
effective and inodorous, has an element of danger in it, when left in
barns in large quantities.
6. Cows or mares that have just aborted, should have the uterus
irrigated daily for a week with a disinfectant solution. Carbolic acid
(1:100 with 1 sodium carbonate) or creolin (1 to 2:100) or mercuric
chloride (1:1000 with 1 hydrochloric acid) are good examples. Use a long
rubber tube and funnel. They should not be bred until all discharge has
ceased.
7. It is a good practice to keep a separate sire for the aborting and
quarantined suspected animals, but the bull for each herd should, after
each service, have his sheath injected with the disinfectant liquid, the
orifice being held and the liquid pressed into all parts and finally,
the skin around the sheath must be well washed with the same.
8. All cows or mares in an aborting herd, or one from which aborting
animals have been removed within a year, should, after delivery, be
injected with a disinfectant for one week exactly as if they had just
aborted. This will guard against the danger from animals that carry the
germ, but have become so tolerant of it that they no longer themselves
abort.
9. New born animals brought in from other herds should be sponged all
over with one of the above-named disinfectant solutions before being
added to the herd.
10. In case the breeding animals go to pasture, separate fields should
be furnished for the aborting and suspected ones and those supposed to
be sound.
11. Breeding ewes, goats and sows should be excluded from all pastures
occupied by suspected herds or those under treatment. The fields should
further be cleared of rabbits as being susceptible to the infection and
capable of keeping it up and transmitting it.
12. It is important to reserve the herd sires for the exclusive use of
the home herds. Where this cannot be done, disinfection of the sheath
and penis should be practised immediately after each service.
Attempts have been made at different times to destroy the bacillus by
subcutaneous or intermuscular disinfectant injections. Bäuer used in the
cow a 2 per cent. solution of carbolic acid, of which he injected two
Pravaz syringefuls under the skin of the flank every fortnight from the
fifth to the seventh month. It was rather unreasonable to expect much
from 10 minims of carbolic acid once a fortnight, even apart from the
fact that this agent is converted into the inert sulphophenic acid in
the body.
Lignieres followed in the same line by injecting into the bodies of the
cervical or other muscles 10cc. (2½ drams) of a mixture of terpinol one
part, olive oil nine parts. This was injected during pregnancy every
second day for the first three months, every third day for the second
three months, and every fourth day for two months. The claim for success
is based on the alleged prevention of second and third abortions in the
same animals, and this becomes rather shadowy when we consider that the
rule with cows is that they do not abort a second or third time. We have
met with veterinarians who claimed a splendid success with the single
injection of the terpinol. Lignieres claims no such success with his
long continued treatment, as he had a percentage of abortions in every
herd treated, and from first to last almost every animal in each herd
aborted once, or was sold nymphomaniac. It is to be feared that the
apparent immunity depended mainly on that tolerance which comes early in
nearly every case to the aborting cow.