102 The Diseases of Animals 



In most cases cracks in the' walls of the hoof are 

 due to a dry, weakened condition of the walls. Severe 

 exertion, especially fast work on hard roads, tends to 

 split the hoof. Cracks may also be caused by an injury 

 to the coronet, where the horny wall is secreted; this 

 interferes with the growth of horn, and a crack results. 

 Excessive growth of the wall in unshod horses may 

 cause cracks. 



Quarter-crack may cause severe lameness. The hoof 

 spreads as the animal steps on it and the soft tissues 

 are often pinched in the crack as the foot is picked up 

 and the crack closes, thus causing 

 the parts to bleed. Sand and 

 gravel may get into the crack and 

 cause trouble, or "proud flesh" may 

 form that interferes with the heal- 

 ing. In some cases there is no 

 lameness, and unscrupulous horse- 

 traders sometimes hide the cracks 



Fig. 25. Quarter-crack by fiHi ng w [th SOap, in Order to 



closed by nails. . to 



dispose or the horse. 



The crack is to be neatly cleaned out; if "proud flesh" 

 exists, it is to be destroyed with a caustic, antiseptics 

 applied to the crack, and then pine tar, to keep out dirt 

 and assist in healing. The crack should be drawn 

 together by a shoeing nail driven across the crack, 

 drawn tightly together and clinched (Fig. 25). It may 

 be necessary to drill the holes for the nails, but in most 

 cases a good shoeing smith can drive them. Small clips 

 are made for this purpose, which can be fitted into 

 grooves on each side of the crack, and closed by large 



