190 THE HORSE IN HEALTH AND DISEASE 



must be broken down in a skilful manner to make the operation a 



success. 



DOCKING 



Draft horses are sometimes subjected to this inhuman opera- 

 tion, which is rapidly falling into disrepute and is now unlawful 

 in most states. Thirty years ago fashion demanded docking for 

 heavy harness horses in order to make them appear "smart." In 

 cases where tumors occur on the tail, or the animal switches and 

 kicks a great deal, it may be removed either by the surgeon's 

 knife or by the docking shears designed especially for this purpose. 

 Restraint is accomplished by the twitch and the side-line. 



NICKING 



Under this term may be mentioned the operations for correct- 

 ing curvature of the tail, and the prevention of the gripping of 

 the reins by the tail. The first operation is the simpler, and 

 consists in simply cutting across the levator or extensor muscles 

 of the side toward which the tail is curved. It is performed sub- 

 cutaneously under the control of the twitch and side-line. If the 

 operation is successful, the tail will be carried in a normal manner 

 after the wound heals. The operation to prevent gripping the 

 reins is more extensive and usually requires that the animal be 

 thrown. It consists in dissecting out and removing about 5 inches 

 of the depressor muscle on each side of the inferior surface of the 



tail. 



UNNERVING 



Unnerving is performed to reUeve pain in a part, to prevent 

 lameness in a limb, or to stop motion, as in the "cribbing" opera- 

 tion. The operation is technically termed neurotomy, and consists 

 in severing or actually removing a portion of a sensory nerve. It 

 should always be performed under either local or general anes- 

 thesia for it is painful. 



Neurotomy should be the last resort for the relief of lameness. 

 When the part is deprived of sensation there is always danger of 

 breakdown in the limbs; besides, if an injury occurs, the animal 

 is not aware of it and serious results follow which may jeopardize 

 the life of the animal. 



The commonly performed neurotomies are digital neurotomy, 

 which has for its object the relief of navicular lameness in cases 

 where plantar neurotomy is not deemed necessary or advisable; 



