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.
CHAPTER II.
CIRCULATORY APPARATUS.
BLEEDING.
Bovine animals are usually bled from the superficial jugular, or the mammary vein.
Bleeding from the Jugular.—The animal having been suitably fixed, the jugular is raised by means of a cord drawn tightly round the base of the neck, and the vessel is opened with a fleam about the middle of the neck.
The skin of the ox being thick, a long-bladed instrument is necessary. When the bleeding ceases, the cord is removed: some practitioners take no precautions as regards the wound; it is better to insert a pin suture.
Bleeding from the jugular may also be performed with the trocar, particularly in animals with fine, thin skin.
Bleeding from the Mammary Vein.—The mammary vein may be opened with the fleam, the straight bistoury, or the lancet. The head is firmly fixed and the hind limbs controlled by a rope passed in a figure of eight above the hocks.
In bleeding on the left the operator places himself at an angle to the animal’s side, opposite the hypochondriac region, with his back towards the animal’s head, and holds the fleam in his right hand. To operate on the right-hand side the fleam is held in the left hand.