RATE OF GROWTH. 103 



regard the average growth as 8 millimetres (^^ inch) per 

 month, the length of time required for complete renewal of 

 the hoof at any point is easily reckoned. But, as before stated, 

 the rate of growth is not always the same. Luncrwitz studied 

 this question somewhat closely and formulated his results as 

 follows : — 



1. The growth of the horny wall is slow and averages about 

 8 millimetres (t% inch) per month. 2. Unshod hoofs grow more 

 rapidly than those shod. 3. Hind hoofs grow more rapidly 

 than fore. 4. The wall grows slower in stallions than in other 

 horses. 5. Growth takes place to an equal extent round the 

 entire hoof. 6. There is no connection between the colour and 

 rapidity of growth of the hoof. 



Growth is favoured by the horse going barefooted. The 

 following case is given in the Hufschmied, v. p. 38 : — 



A horse, the normal growth of whose front hoofs was 3 

 millimetres monthly, was sent to grass without shoes for three 

 months. A light cantharides blister was applied around the 

 coronet. During this period the growth rose to 8*9 millimetres 

 per montli. 



In horses which are shod, growth is favoured by free move- 

 ment on moderately soft ground, by careful shoeing which 

 provides for the expansion of the foot, by regularly shorten- 

 ing the wall, by nourishing diet, normal state of health, and by 

 all factors which increase local circulation. Growth is retarded 

 by want of movement, ill health, low condition, exercise on hot 

 sand or on stones, drought, excessive length of the hoof, unequal 

 distribution of wei2;ht in the two limbs, and by continued 

 standing on one foot. 



Wear depends to some extent on the pace. Thus at a full 

 gallop or fast trot the heels seem to wear most, at a walk or 

 slow trot the toe. That is to say, that at a fast pace the foot is 

 brought liat to the ground or even with the heel first, but at a 

 walk the toe strikes the ground first. It is worthy of note 

 that draught horses usually wear the outer quarter more than 

 the inner. 



The question of how the hoof grows cannot well be answered 

 by direct inspection of the parts, and requires a careful study 

 of the formation of the specialised corium, which produces the 

 horn, of the microscopic appearances of the horn itself, and of 



