DETERMINING THE AGE OF STOCK 169 



At 7 the "clips'' or marks begin to disappear from the 

 lateral permanent incisors. 



At 8 the "cups" or marks begin to disappear from the 

 corner permanent incisors. 



The wearing-away process is shown more particularly 

 in the "cups" or dark, oval rings in the teeth. This at 

 first extends clear across the face of the tooth, but as 

 the tooth wears down the ring draws in until finally it 

 almost disappears. It is as if there were a small dark- 

 colored inverted cone in the tooth. As this cone wears 

 down the diameter of the base gradually lessens until it 

 becomes a mere dot or point. 



The feed given a horse has much to do with the wear- 

 ing away of the teeth. There is a tremendous difference 

 in this respect between horses raised in an alfalfa coun- 

 try where very little or no corn is fed and those raised 

 in a corn-growing region, the latter showing far more 

 wear on the teeth. In Arizona we used to think that 

 as between two horses, one born and raised in the 

 mountains and the other in the sandhill ranges, the 

 latter showed a great deal more wear on his teeth, 

 due to the grinding effects of the sand picked up in 

 grazing. 



However, after eight or nine years the determination 

 of the age of a horse is more or less a matter of guess- 

 work, as the teeth furnish no sure evidence of the animal's 

 age. 



The supra-orbits or soft places above a horse's eyes 

 are one test most commonly used. In the young horse 

 the skin here is nearly level with the rest of the fore- 

 head. With advancing age it begins to hollow out until 

 in a horse over ten or twelve the cavities are very deep. 

 Also the ears offer another means, as with age they begin 



