SECTION XI.. Operations.

OPERATIONS.

CHAPTER I: CONTROL OF ANIMALS.

CONTROL OF OXEN.

The safe and efficient performance of surgical operations renders it necessary that the animal should first of all be placed under complete control. This precaution, therefore, is the first to merit attention. Animals are either secured completely or to a more or less limited extent, according to circumstances. The ox, for example, may be secured by the head, one or more limbs may be fastened, or, by being placed in a trevis, the whole of the animal may be secured.

PARTIAL CONTROL.

(1.) The simplest method of securing the ox is to grasp the nostrils or lower extremity of the septum nasi between the thumb and index finger of the right or left hand (Fig. 57).

(2.) This method may be rendered more complete by the assistant passing his arm from behind forward over the animal’s head between its horns, and then grasping the nostrils as above described, whilst one of the horns is firmly held with the other hand (Fig. 58).

(3.) A third method consists in fixing the head to a post, tree, fence, or other solid body, by passing a rope round the base of the horns and tying it to the object selected.

CONTROL OF THE LIMBS.

To prevent the animal kicking or moving about during an operation it is sometimes necessary to fix the limbs. A front leg may be lifted as for shoeing, or may be kept lifted by means of a rope passed around the fetlock, over the withers, downward between the front legs, outside the forearm, in front of the chest and inside the pastern, after which one or more turns may be made around the pastern to prevent the rope slipping.

A hind limb may be secured in a simple way by passing the end of the tail round it in front of the hock (Fig. 284); any violent and extensive movement of the limb is then necessarily painful to the animal owing to the tension of the tail.

Greater security, however, is given by passing a rope backward and forward around the hind legs, above the hocks, in the form of a figure of eight (Fig. 285). This does not prevent all movements of the hind limbs, but it limits them and secures both animal and operator from danger.

Should it become necessary to examine the hind foot or interdigital space, it is useful at times to pass a loop of cord round the leg in the region of the tendo-Achillis, and to twist and tighten this loop by a short, stout stick passed through it; this is the leg twitch described in Dollar’s “Operative Technique,” p. 7.

For such examinations, however, the animal is usually placed in the trevis, or is secured to the side of a long waggon (Fig. 286).

To secure the limbs beneath the abdomen a strip of webbing or a rope is fastened round the pastern, passed between the fore limbs, then in front of the shoulder of the opposite side, over the withers and beneath the elbow of the same side, being secured with a slip-knot.

For castration in the standing position a hind and a fore limb may be fastened together, as shown in Fig. 287.

In examining the sole of the hind claws, the animal’s head may be secured to a tree, and the hind limb lifted by a strip of webbing or rope fixed to the body of a waggon (Fig. 288).

GENERAL CONTROL.

General control in the standing position can only be made really effective by using the trevis, in which both the head and the fore and hind limbs are secured.

The practitioner, however, is often content with much less perfect methods, using either the so-called “bulldogs” or the nose ring, which may usually be so manipulated as to control all but the most dangerous animals. The nose ring is seldom employed except for bulls, which are usually ringed at an early age; the “bulldogs” can be employed and removed at will.

In inserting a nose ring the head is securely fixed, the centre line of the muzzle is grasped with the left hand, and the septum nasi is pierced with a straight bistoury, the cutting edge being turned in a backward direction; the aperture being thus prepared, the ring is introduced and fixed. Some operators prefer to use a trocar, slightly exceeding in diameter the ring to be worn; in that case the manual technique is the same. The puncture is made, the trocar alone is withdrawn, and the canula remains in situ; one extremity of the ring is then inserted into the canula, and both are drawn through the septum together. There is no difficulty in thus inserting the ring, though puncture with the trocar is perhaps rather less convenient than with the bistoury.

Relative control without casting may also be effected by attaching the end of the tail to the base of the horns or the head to the cannon bone of a front or hind limb. These methods, however, are of little value except to prevent animals at grass from escaping entirely during operation.

CONTROL BY CASTING.

Oxen should always be cast on a thick straw bed to avoid fracturing the horns.

The simplest method consists in using hobbles and ropes, as for the horse.

Another, though less practical, method consists in using two long ropes, each fixed to the base of the horns and passed first between the front, then the hind limbs, round the hind pasterns from within outwards and then brought forward (Fig. 292). When the ropes are drawn tight by assistants standing in front of the animal, the latter usually falls on its hocks and rolls over to the right or left, according to the direction given to it.

A third method is particularly useful in young or feeble animals. It consists in fixing around the horns a rope about eight to ten yards in length, the free end of which is carried along the upper margin of the neck and back. A loop is formed embracing the base of the neck, a second behind the shoulders in the region occupied by the girth, and a third around the flanks (Fig. 293). By pulling in a backward direction the rope is drawn tight, and the animal first backs and afterwards falls on its hocks, subsiding either to the right or left, as in the case previously mentioned.

In using either of these two methods it is very important, as soon as the animal falls, to secure the limbs in a certain way, according to the nature of the operation to be performed. This can be effected with hobbles and ropes passed round the hocks, above the knee, etc.

CONTROL OF SHEEP AND GOATS.

The above animals may be secured, whilst standing, by grasping the head and neck or, when cast by crossing the front and hind limbs in the form of an =X= and tying a soft rope or piece of webbing round the crossing of the limbs.

CONTROL OF PIGS.

No difficulty is usually experienced in controlling young pigs, either when standing or cast, only one or two assistants being required, but aged animals are more difficult and more dangerous to deal with, and by their tusks sometimes inflict severe wounds.

In the standing position they can be partially fixed by passing a running loop behind the canine teeth of the upper jaw, but should the examination to be carried out prove to be of a difficult character it is best to cast the animal.

A strong assistant grasps one of the hind limbs by means of a running loop, fixed, for example, above the right hock. He rapidly slides his left knee towards the front of the left side of the chest, passes his left hand over the withers, and by the combined use of his knees and arms throws the animal on its left side, controlling as far as possible the struggles of the right front and hind limbs, which he grasps with his hands.

The animal is then further secured by rapidly passing a thin rope in figures of eight around the front and hind limbs. If necessary all four legs may be brought together and fastened by a rope passed round the region of the pastern; a muzzle can afterwards be applied to prevent biting.

ANÆSTHESIA.

Oxen rarely receive general anæsthetics, though in certain obstetrical cases they may be necessary. Ether and chloroform are given by inhalation, and chloral of 10 to 20 per cent. strength by intravenous injection. In utilising the latter method the injection should be made slowly, the pulse and heart being closely scanned to prevent cardiac syncope. The dose of chloroform varies with the size of the animal, 2 ounces often sufficing for a full-grown ox. The same methods may be used for sheep, goats, and pigs, the doses being suitably altered. (For fuller particulars see Dollar’s “Operative Technique,” pp. 44 to 70.)

Most frequently, however, the surgeon contents himself with producing local anæsthesia by the injection of a 4 to 10 per cent. solution of cocaine.