MILK PRODUCTION 239 



sent the average for the whole country. A few years ago, 

 in Illinois, a careful study was made of the production of 

 36 dairy herds containing 554 cows. Of this number the best 

 fourth yielded a profit of $31.32 for each cow, while the 

 lowest fourth gave a return of only 77 cents per cow. On 

 this basis, it would take forty poor cows to yield the same 

 profit as one good one. 

 The foundation herd may be gradually improved by elimi- 



Ayrshire Cow 



nating low-producing cows (using the Babcock test and milk 

 records), and by applying the principles of grading. When 

 grading the herd a well-bred sire will make an improvement 

 even in the first generation. The influence of the sire is 

 illustrated by the following examples. A scrub cow, whose 

 best record was 3534.3 pounds of milk and 190.29 pounds of 

 butter fat, produced a daughter with a record of 5137.7 



