A complete bacteriological study was made of the genital tracts of
fourteen normal young veal calves (six to twelve weeks old), four mature
fertile bulls, and sixteen mature bulls, either sterile or impotent to
some degree. Together with these, the tracts of eleven aborted fetuses,
seven calves dying from calf infections (scours or pneumonia), and
sixteen bulls slaughtered at an abattoir were studied bacteriologically.
Occasionally, studies were made of individual seminal vesicles or
testes, when these parts alone were brought or sent in. The history of
the abattoir animals was, of course, quite indefinite or entirely
negative. On the killing floor, many tracts could be studied for
pathological changes, but in the bacteriological work it was difficult
to care for more than two tracts on each visit.
The results of the bacteriological examinations are given in the
appended tables, in which the tracts are divided into six groups. The
results in Group I. consisting of normal veal calves, indicate that the
genital organs of young male calves are, under normal conditions, free
from bacteria. Carpenter (9) obtained like results in examining the
genital tracts of heifer calves. The cultures made from the seminal
vesicles and testes of all these veal calves were, with two exceptions,
negative. Both seminal vesicles of one tract and one of another yielded
cultures of _Staphylococcus albus_.
Adult bulls of known fertility were naturally difficult to obtain, only
the four animals in Group II being available for examination. Two of
these (Nos. 1 and 2) were from the experimental herd kept by the
department, and at all times had a good breeding history. The other two
were good breeders, but were slaughtered because of poor pedigrees. Bull
1, raised in the department herd, had a severe attack of scours when a
few weeks old, while the calfhood history of the other is not known, he
having been purchased after reaching sexual maturity. The cultures from
the genital organs of the former (Bull 1) were entirely negative, except
those from the left epididymis and scrotal sac, which yielded growths of
_Streptococcus viridans_. All the organs of the tract from this animal
were normal, except for the fact that numerous strands of connective
tissue extended from the serous covering of the tail of both epididymes
to the adjacent part of the parietal layer of the tunica. The tract of
the other failed to show any organisms. The only evidence of any
abnormality was the presence of the same connective tissue strands on
the tail of the epididymis, as in the first tract. The other two bulls
gave negative cultures from all parts.
Of the sixteen bulls in Group III, slaughtered at abattoirs, and in
which no history was available, eight failed to show the presence of any
organisms in their genitalia. Of the others, the vesicles yielded
cultures of _Staphylococcus albus_ nine times, and _streptococci_ four
times. _Staphylococcus albus_ was recovered once from the prostate, and
once from Cowper’s glands. The testes gave cultures of staphylococci in
two cases, and _Bact. abortum_ in one. No observable anatomical changes
accompanied the presence of the Bang bacillus in this case. The
epididymes showed growths of staphylococci five times, and streptococci
on three occasions. _Streptococci_ were isolated from the scrotal sacs
of eight testes.
The results in Group IV (aborted fetuses) show that bacteria are often
present in the seminal vesicles or testes of these animals. As a rule,
however, the organisms are identical with those isolated from the blood
or other parts of the animal. This is to be expected, however, for
because of the feeble resistance of the fetus to any infection, the
organisms circulating in the blood may be isolated, as a rule, from many
different organs and tissues. All samples of blood set with _Bact.
abortum_ antigen were negative, irrespective of whether or not the
organism was recovered from the blood or other tissues. This is in
accordance with the findings of Carpenter in the female fetus,—the
resistance is so feeble that few or no antibodies are formed to combat
any existing infection. _Bact. abortum_ was recovered in two cases from
the vesicles, and in four cases from the testes, but in each instance
the same organism was present in the blood or other tissues of the body.
The results from the tracts of the calves dying of calf infections are
given in Group V, and show that five were negative. The other two showed
_B. coli_, staphylococci, and streptococci, in the organs indicated by
the chart.
In Group VI, the mature infertile or sterile bulls, there was a
comparatively wide variation in the type of organisms encountered, but
streptococci and micrococci were the most common invaders. In the order
of the frequency of infection, the organs would be enumerated as
follows: Vesicles, epididymis (usually the tail), scrotal sac, testes,
prostate, and Cowper’s glands. The first three parts mentioned usually
contained bacteria. A streptococcus was the usual invader of the scrotal
sac, and very probably was the cause of the connective tissue tufts and
strands so frequently seen. The vesicles and epididymes gave, in the
order of the frequency of their occurrence, staphylococci, streptococci,
_B. coli_, and _Ps. pyocyaneus_. The streptococci were usually of the
viridans group, though a few were hemolytic, and two strains were
indifferent to blood. The testes gave growths in only eleven
instances,—staphylococci eight times, streptococci two times, and an
unidentified rod once. The prostate yielded staphylococci twice and
Cowper’s gland once.
As emphasized previously, the vesicles and tail of the epididymis are
most subject to infection and degenerative changes. At the same time,
they are intimately connected with the secretion of the semen. Once the
epididymis becomes infected, there is nothing to prevent the organisms,
together with inflammatory products, from being mixed with the semen and
ejaculated during coitus. Also in the vesicles, unless the inflammation
is so severe as to occlude the excretory duct, the organisms are mixed
with the vesicular secretion, which is emptied into the urethra during
ejaculation. Carried along with the bacteria, are, of course, toxic
products, degenerated cells, and the otherwise altered secretion of the
glands. One interesting case noted was that of a bull that had passed
from a state of fertility to that of complete sterility during a period
of two months. The semen was semi-fluid, greenish yellow in color, and
contained a very few non-motile spermatozoa. Post mortem examination
showed that the vesicles had undergone abscess formation and that they
contained yellowish green material similar to that which had been
discharged during copulation. _Streptococcus hemolyticus_ and _Ps.
pyocyaneus_ were isolated from both vesicles, and from the semen.
_Micrococcus albus_ was isolated in nearly all cases of vesiculitis and
was often associated with _Streptococcus viridans_ or _hemolyticus_.
Bacteriological studies of the semen are, on the whole, more or less
unsatisfactory, due to the present difficulty in obtaining samples free
from any chance of contamination. In most of the abnormal bulls,
bacteria of various types were isolated from the semen, most of which
agreed culturally with those later isolated from the internal genital
organs of the same tracts. The method of culturing consisted of douching
the prepuce of the bull and vagina of the female with sterile saline
solution before breeding. Samples of vaginal mucus were taken before
service, and the flora compared to that after douching. This method of
douching produced vaginal samples relatively free from bacteria, at
least so much so that the post coital fluid demonstrated that many
organisms must have been introduced from without. Whether or not they
came in with the semen is problematical, but in all probability this was
the method of introduction.
I have so far failed to obtain _Bact. abortum_ from the tract of an
adult animal, either by direct culture or guinea pig inoculation, except
from the testicle of one abattoir bull. The agglutination tests with
_Bact. abortum_ antigen were all negative, except for two abattoir
bulls. The results so far obtained would seem to indicate that, in
accordance with the findings of other workers, the Bang organism seldom
invades the male genital tract, or does not thrive there after its
introduction. Schroeder (12) and others, have, however, on various
occasions, recovered the organism from the bull, and the former author
even states that it invades the vesicles and is eliminated with the
semen.