PASSING THE PROBANG.
Passage of the probang is called for in cases of marked tympanites, suspected dilatation or contraction of the œsophagus, and accidental obstruction. Special or improvised instruments may be used, according to circumstances.
The animal is secured in a standing position with the head extended on the neck and in a straight line with the body. A gag is placed in the mouth and the tongue is grasped and withdrawn by an assistant, whilst the operator, having carefully oiled the probang, passes it through the gag towards the back of the pharynx. Violence should be avoided, the probang being gently slid along the centre of the vault of the palate. When the animal makes swallowing movements, the apparatus is slowly pushed onwards.
This manipulation, though simple, requires some dexterity, because at the moment when the instrument enters the pharynx the animal often thrusts it to one side or the other with the base of its tongue, bringing it between the molar teeth, and so crushing, or at least injuring it.
The passage of hollow probangs gives comparatively little relief in cases of tympanites, because the probang is almost always obstructed by semi-digested material from the rumen, or plunges into the semi-solid masses of food contained therein.
When the œsophagus is dilated at a point within the thorax, the progress of the probang is checked by the accumulated food material, and it becomes possible to determine approximately the place where the dilatation occurs. In the same way, should a slender probang be arrested at a given point in the œsophagus, this indicates that there is contraction of the tube at that point.
In cases of obstruction the cupped probang is always arrested by the foreign body. Efforts to thrust the latter onwards should always be made with great caution, otherwise the œsophagus may be greatly distended or its walls even ruptured.
CRUSHING THE FOREIGN BODY.
No attempt should be made to crush a foreign body within the cervical portion of the œsophagus unless it is quite certain that that body is of comparatively soft character. Crushing may be performed by lateral pressure with the fingers within the region between the two jugular furrows, or mechanical means may be adopted.
In the latter case a small piece of board is applied to one side of the neck behind the foreign body, whilst gentle blows are given from the opposite side with a little wooden mallet. Whatever precautions may be taken, however, this method cannot be recommended.