200 THE HORSE IN HEALTH AND DISEASE 



old should usually have the shoes set every three weeks, while an 

 aged horse may go four weeks or longer. When the shoes are left 

 on too long corns may develop, or the nails work loose and injure 

 the feet. 



The horseshoe in common use is machine turned, so must be 

 fitted to the foot before being nailed on. There are shoes for front 

 and hind feet and for right and left feet. They should be no 

 heavier than will suffice for about one month's wear. The fuller- 

 ing is the groove on the lower surface of the shoe. It aids to pre- 

 vent slipping and has the nail holes punched in it. Chps are ear- 

 like projections drawn up at the toe and quarters to more firmly 

 attach the shoe to the foot and take the strain off the nails. Calk- 

 ings are placed at the toe and heels. They are useful to prevent 

 slipping. The heel calk is turned at a right angle to the bar of the 

 shoe. Somtimes the outer calk is turned horizontal to the bar. 

 Summer shoe calks are blunt. Winter calks are sharp. Four- 

 calked shoes are used to bring about certain kinds of toe action. 

 Never-slip calks are useful for horses driven on city streets. They 

 are objectionable, for the reason that they may break off or cause 

 serious calk wounds. Their advantages are the quickness and con- 

 venience of application and sharpening. If calks are turned at the 

 heels only, the toe of the shoe must be left thicker than the branches 

 to avoid disturbing the normal setting down of the foot as little 

 as possible. 



The bar-shoe is used extensively in the cities. It is especially 

 adapted for heavy draft horses with brittle walls and heels that 

 are weak, low, or contracted. The bar rests on the frog and thus 

 affords frog pressure. For horses which habitually pull their 

 shoes oif, either by getting them caught or by stepping on them, 

 this shoe is best. It should not be used if navicular disease 

 is present. On the other hand, it is the most suitable for many 

 other forms of disease of the feet. 



The snow-shoe is one well beveled on the inner border of the 

 ground surface to prevent snow-balling. It is especially useful 

 when the snow is damp and packs easily. 



A shoe to prevent mud slinging is made in a similar fashion. It 

 is used on light harness horses which have a tendency to sling mud. 



The nail plate is made of two pieces of sheet steel riveted to a 

 C-shaped strip of tarred canvas. The latter is interposed between 

 the hoof and the shoe, so that the metal comes in contact with the 



