HORSESHOEING. 



163 



5. Thrush of the Frog. 



When the horny frog is ragged and fissured, and an ill-smelling, 

 dark-colored liquid collects in the lacunse of the frog, it is affected 

 with thrush. When thrush exists uninterruptedly for several 

 months the perioplic band is irritated and forms rings of periople 

 which assume an ir- 

 regular course and 

 cross the rings of the 

 middle layer of the 

 wall and each other 

 at various angles (Fig. 

 139). 



The causes are : un- 

 cleanliness, too little 

 exercise in fresh air, 

 excessive paring of 

 the frog, the use of 

 shoes with calks by 

 which the frog is per- 

 manently removed 

 from the ground, and the use of frog-pads which are kept on 

 from month to month. 



The consequences are, besides contraction of the hoof, soreness 

 in travelling, a shortening of the step, and, occasionally, well- 

 marked lameness. 



Treatment. — Removal of all greasy horn from the frog, and of 

 the prominent overgrown angles of the buttresses (see page 85), 

 thorough washing of the frog once or twice daily, abundant 

 exercise, and shoes without calks. 



Hoof "ivlth irregular superficial rings resulting from thrush 

 of the frog. 



