156 



HORSESHOEING. 



coronary cracks; those which are limited to the lower border of 

 the hoof are sometimes designated low cracks ; while those which 

 are continuous from one border to the other are called complete 

 cracks. If the crack passes through the entire thickness of the 

 wall to the sensitive tissues underneath, it is called a deep or pene- 

 trating crack, in contradistinction to the superficial crack (Fig. 135). 

 Causes. — There are many. Besides wounds of the coronet, 

 everything that impairs the elasticity of the horn, weakens the 

 hoof, and causes an overloading of one-half of the hoof. Fur- 

 thermore, great dryness and excessive work on hard streets. 



Prognosis. — This will depend upon the age, kind, and location 

 of the crack. A low crack is without significance unless it is the 

 remnant of an old coronary crack which has grown down. Coro- 

 nary cracks, on the contrary, are more serious because of the 

 lameness which often accompanies them, and especially on ac- 

 count of the long duration of the healing process. 



The borders of the crack never grow together, and healing 

 can only take place through healthy, unbroken horn growing 

 down from the coronary band. 



(a) Treatment of Coronary and Bar-Cracks. — If practicable, 

 allow the affected horse to go barefoot ; otherwise, the use of 



the bar-shoe for all cracks is ad- 

 vised, because it will continuously 

 protect the diseased section of wall 

 from pressure by the shoe. If there 

 are present still other diseases of the 

 hoof (corns, contraction, flat or full 

 hoof), the addition of a leather sole 

 with packing will be most beneficial, 

 not only in favoring the healing of 

 the crack, but also in improving 

 the form of the hoof and in favoring 

 the cure of the other lesions. In all coronary cracks it is of 

 advantage to assist healing by fastening or immobilizing the 

 borders of the crack by one of the following methods : 



Fig. 135. 



Hoof exhibiting a coronary crack, a 

 plantar or low crack, and a complete 

 deep crack, the latter with a nail ready 

 to be clinched. 



