Cooperative Work with Columbia University 



307 



to tlie bisexual reproduction, a dairy cow that will " breed abso- 

 lutelv true " is practically impossible to obtain ; but that we can 

 approach much nearer to this ideal than we have in the past has 

 been demonstrated in the last few years. 



To illustrate this principle by a practical example of what we 

 should strive for in the selection of our breeding cows and sires, 

 it is easiest to consider the animal's pedigree. It is not enough 

 that her sire has produced good offspring or that her dam pro- 

 duced a large amount of milk, but we should also know what her 

 sisters are producing, and what the ancestry for several generations 



Fig. 556.— The Dairy Type 



have produced. This is no longer impossible, since wc have the 

 advanced registry records. If the production has been uniformly 

 good throughout a number of generations, we have much more 

 reason to expect that the individual we are considering will be a 

 good one than if she came from a high-producing animal whose 

 relatives were poor producers. 



We should not overlook in a discussion of animal breeding the 

 great improvement that has been accomplished by what we know 

 as ^' grading," that is, by the use of pure-bred sires on grade or 



