160 HORSESHOEING. 



because a renewal of the coronary crack will be followed by a 

 low crack. 



In order to remove these cracks it is sufficient merely to shoe 

 the horse. Upon shod horses they may be prevented by using 

 properly punched shoes and thin nails. The lower border of 

 the wall near the crack should be reheved of pressure by cutting 

 out a half-moon-shaped piece of horn. To prevent the crack 

 from extending farther upward we may burn a transverse slot at 

 the upper end of the crack, in as far as the leafy layer of the 

 wall, or cut such a slot with a small hoof-knife. 



2. Clefts. 



An interruption of continuity of the wall, at right angles to the 

 direction of the horn-tubes, is called a oleft. 



Clefts may occur at any part of the wall ; yet they occur most 

 often upon the inner toe and inner side, as a result of injury 

 from sharp, improperly placed heel- calks (see page 138). How- 

 ever, suppurating corns, or other suppurative processes situated 

 at the coronet or which find their point of escape at the coronet, 

 may from time to time lead to separations of continuity and the 

 formation of horn-clefts. 



Horn-clefts, though the result of lesions which are often very 

 injurious and interfere with the use of the horse, are of them- 

 selves not an evil which can be abolished or healed by shoeing, 

 although, in many cases, proper shoeing would have prevented 

 them. A horn-cleft is not a matter for consideration by the 

 shoer until it has grown down so far that it comes within the 

 region of the nails. 



In order not to disfigure the hoof unnecessarily, the horn 

 below the cleft should be kept in place as long as possible by 

 shortening the wall at that point, to remove shoe-pressure, and 

 by driving no nails into it. If, however, the horn is loose and 

 about to come away, it should be removed and the defect filled 

 with grafting-wax or, still better, with Defay's patent horn- 

 cement. 



