58 A TEXT-BOOK OF VETERINARY OBSTETRICS
in drawing in the fluid by contracting during coitus and relax-
ing afterwards, so causing an aspirating action. The sperma-
tozoa have been found in the uterus of the sheep, mare, and
bitch a few minutes after copulation. Semen is often found
in considerable quantity in the vagina of the cow and mare.
Probably the spermatozoon travels forwards along the uterus
to the horn, and even to the Fallopian tube, and there fecun-
dates the ovum. That it must sometimes travel so far
forwards as the Fallopian tube is evident from the occurrence
of extra-uterine—ovarian or tubal—gestation. In the former
case the spermatozoon must have even reached the ovary.
The time taken for the spermatozoon to travel forwards and
fertilize the ovum varies with individuals and species from
some minutes to a few days. Since ovulation occurs generally
towards the end of oestrus, it is probable that service is more
likely to be successful when it takes place towards the end of that
period. v If the ovum is not fertilized, it perishes or is ejected.
Injuries during Coition.
Sometimes when a mare is not at the proper stage of
oestrus, and is approached by the stallion, she attempts to
kick at him, and may even cause fracture of certain bones ol
the limbs. This is avoided by first trying the mare, to find if
she is at the proper stage to take the horse, and by hobbling
her during the act.
False copulation, or entrance of the penis into the rectum
instead of the vulva, occasionally occurs in the mare, more
rarely in the cow and sow. It is caused by restlessness of the
female, contraction of the vulva, and sometimes as the result
of carelessness on the part of the groom in handling the stallion.
The effect is highly dangerous. Sometimes the rectum is
ruptured and the peritoneum is opened, particularly if hard
fasces are present in the rectum; in this case a fatal peri-
tonitis usually results. Where the rupture occurs in the last
foot of the rectum, and the peritoneum is not opened, the
animal may recover. The diet should be sparing and laxative,
the faeces should be frequently removed from the wound cavity,
and the latter cautiously washed out twice daily with a mild
antiseptic lotion. The healing of the wound, if it does occur,
is slow.