300 ILLINOIS DAIRYMEN'S ASSOCIATION. 



ing city. With this thought in mind, let us study his problem to 

 see if there is any necessity on his part to determine the individ- 

 ual capacity of his own cows. If for convenience we assume 

 that the cost of food was uniform, then the return per cow for 

 milk at $1.15 per hundred varied from $39.40 to $102. 15 per 

 year. Between these extremes there are all gradiations of pro- 

 duction from a cow that hardly pays expenses for food to those 

 that are decidedly profitable. It is not to be supposed that the 

 cost of feeding the different cows was uniform, it being larger 

 perhaps in cases of liberal production, yet it should be understood 

 that the cost was not in proportion to the production, which fact 

 goes to emphasize the difference in the ability of certain cows to 

 use food economically. In this herd, then, some cows were not 

 producing as much milk from a given amount of food as 

 were others, consequently, the only rational procedure was to 

 find out which they were and to replace them by individuals that 

 use food to better advantage. Hence the necessity for weigh- 

 ing the milk and testing for butter fat in order to keep the quali- 

 ty up to requirements. Whether used for direct consumption 

 or buttermaking a knowledge of the butter fat content of milk is 

 imperative. 



The results obtained by testing herd No. 21 show clearly 

 the necessity of "spotting the robber cow." By removing a few 

 individuals of low capacity the return from the remaining cows 

 may be largely increased as shown in Table 8, Herd No. 7. In 

 Herd No. 21, cow No. 7 is decidedly profitable, but such cows as 

 No. 11 do not contribute very rapidly to the dairyman's wealth. 



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