Finally, it may happen that castration does not prevent the recurrence of œstrum. The ovarian pedicle may have been divided too close to the glandular tissue, a fragment of which has remained adherent to the pedicle.
Certain other operative complications are also possible in dealing with cows suffering from nympho-mania which have developed cysts, tumours, or abscesses of the ovaries. It is then necessary to enlarge the incision in the vagina and take particular precautions not to rupture the cysts or abscesses in the peritoneal cavity. The operator must proceed cautiously and modify his technique according to circumstances.
CASTRATION OF THE SOW.
Castration of the sow has been practised since very ancient times. The operation is performed on animals intended for fattening, and at all ages between six weeks and maturity.
Anatomical Arrangement of the Genital Organs.—Before performing ovariotomy in the sow it is indispensable to understand the special arrangement of the genital organs. The uterine horns are very long and folded on themselves, forming convolutions which give them somewhat the appearance of small loops of intestine. Nevertheless they can readily be distinguished by the touch, for they are much smaller in size than the latter.
In young sows, two to three months old, they are of about the thickness of a small pencil. Differentiation is more difficult in sows that have borne litters, but as the ovaries alone are withdrawn, leaving the horns of the uterus uninjured, this distinction is unimportant.
The horns of the uterus are suspended in the peritoneal cavity by means of very extensive, well-developed, and very lax ligaments, and, as the horns of the uterus lie at a very acute angle one to the other, the ovaries are very close to the median line of the abdomen. The length and yielding character of the parts and the close apposition of the ovaries explain why the latter can be found and extracted through a single incision in the flank, either on the right or left side.
An ordinary convex bistoury or a special knife and two artery forceps are the instruments employed.
Manual Technique.—The animal is cast on the right or left side, preferably on the right, so that the right index finger can be employed. Full-grown sows should always be muzzled. In the case of young animals, the limbs should be grasped by assistants, the hind limbs being crossed one over the other and drawn backwards.
Antiseptic applications are highly desirable, although they are usually neglected when a layman directs the operation.