CHOOSING A COW 189 



each pair is up and in full wear may be estimated as 

 follows : — 



First or middle pair of permanent teeth 18 months 



Second or first intermediate pair of permanent teeth . . 27 months 



Third or second intermediate pair of permanent teeth . . 36 months 



Fourth or lateral pair of permanent teeth 45 months 



If there is a variation for this table, the cow is likely to be 

 older rather than younger than the teeth indicate according to 

 the ages. In fact, some authors say the first pair of permanent 

 teeth appear at two years of age ; the second pair at three ; the 

 third pair at four ; and the fourth pair at five years of age. 



The permanent teeth of the cow differ in many respects from 

 those of the horse. After they are up and in wear there is com- 

 paratively little change for a few years. They are never firmly 

 fixed in the jaw, as are the peritianent teeth of the horse. 



As the animal grows older the teeth become narrower, and 

 by the ninth year there is much space between them. They 

 shrink away from each other and often become more or less 

 discolored and finally drop out one by one. 



Examination of the horns. — The horns of cattle are often 

 used in estimating the age. During the first two years the horns 

 grow rapidly, and in this time they make approximately their 

 entire growth. After two years of age, the growth is slow, and 

 each year's addition is marked by a more or less distinct ring. 

 The first ring does not make its appearance until the animal is 

 approximately three years old. The age is estimated, there- 

 fore, by adding two to the number of rings present. 



CHOOSING A DAIRY COW 



The dairy cow is desired for her ability to secrete milk at a 

 profit. In estimating the value of a dairy cow there is no 

 method so satisfactory as the actual record of her performance 

 as determined by the scales and the Babcock test. Having 



