FORM AND ACTION OF THE FOOT. 17 



Gro-wth of Hoof. 



Like every otlier part of an animal body, the hoof is 

 constantly changing. Wear and tear cause waste of the 

 horn, which is replenished by growth. When wear 

 exceeds growth the foot becomes denuded of horn, and 

 lameness results. When growth exceeds wear, the hoof 

 becomes disproportionately long, and some parts suffer 

 by the overgrowth of others — for instance, whenever the 

 heels are unduly high, the f rog'becomes small and weak. 

 In a state of nature, the horse's foot keeps itself of pro- 

 portionate form. On hard ground, the hoof is worn 

 away as quickly as it grows. On soft ground, it may, 

 for a time, become overgrown, but this is rectified by 

 the soft horn becoming fractured and broken off. In 

 enclosed, cultivated grounds, the movements of the horse, 

 even on grass land, are too limited to ensure a propor- 

 tionate form of hoof. When horses are turned out 

 without shoes, the feet should not be left to take care of 

 themselves, unless the pasture is of large area and the 

 time at grass extends for several months. 



In a hoof which is overgrown — and all shod feet 

 become overgrown in four or five weeks — there is ai3par- 

 ently a greater excess of horn at the toe than elsewhere. 

 This is due to the oblique direction of the wall at the toe, 

 and to the fact that the horn fibres of the hoof do not 

 grow down vertically, but obliquely forward. When 

 the natural wear of the hoof is prevented, the effect of 

 growth is to lengthen the toe and carry forward the 

 bearing surface of the foot. Now, this bearing surface 

 has a proper relative position to the limb above it. 

 Therefore a disproportionate foot must injuriously affect 

 both the action and position of the whole limb. 



The rate at which the wall grows varies greatly in 

 different horses, and is affected by external conditions. 

 The good average wall grows nearly one inch in three 

 months, and the whole hoof is rejjlaced in from ten to 

 fifteen months. The hoof grows more rapidly when a 

 horse is actively exercised than when he is confined in a 

 box. Febrile diseases check growth, and irregularities 



