242 MANUAL OF FABM ANIMALS 



production, although a few individuals may show marked 

 improvement. This will prove the skill and patience of the 

 breeder. 



Continued judicious selection the means of improvement. — 

 The few individuals of the second generation that show the 

 marked improvement are the ones to be relied on to carry 

 the herd forward in the improvement. Their female offspring 

 will in turn show many inferior to themselves, with only a few 

 superior ones. It is the continued and judicious selection from 

 the high-producing and the discarding of the low-producing 

 that improves the general average of the herd. As generations 

 come and go, characteristics of the pure-bred sire will become 

 more and more fixed and uniform. Reversions towards the 

 low production of the common-bred ancestors will be less and 

 less frequent. The herd will be practically pure-bred from the 

 standpoint of the capacity of the individual animals to re- 

 produce their characteristics, although they can never become 

 eligible to registration in a herd-book. 



This plan of grading-up has been successfully practiced in the 

 improvement of a large number of herds of dairy cattle, and is 

 entirely within the reach of any one. As an example of this 

 plan there is shown in the table (p. 243) the improvement that 

 was secured in the case of a herd descending from a single in- 

 ferior cow. 



The table shows a very rapid improvement for the first two 

 generations, and for the next three it just about holds its own. 

 There are two reasons why the third, fourth, and fifth genera- 

 tions do not equal the second : first, because they contain many 

 heifers which have not yet reached maturity and serve to pull 

 the general average down ; and second, there are a large number 

 of animals taken into account. 



While the plan has been applied to the improvement of a herd 

 starting with a common cow, it should be remembered that the 

 same principles apply equally well to any herd. There are very 



