DAIRYING. 39 



three cows giving 4,000, 6,000, and 8,000 pounds of milk, each 

 testing 3.5 per cent, fat, the value of this milk on a butter basis 

 may be calculated as follows: 



4,000X3.5:= 140XU6=162 



6,000X3.5=210X1-16=243 



8,000X3.5=280X1.16=325 



Value of the Skim milk : 



4,000X80 per cent, equals 3,200X30 cents, equals $ 9.60 

 6,000X80 per cent, equals 4,800X30 cents, equals 14.40 



8,000X80 per cent, equals 6,400X30 cents, equals 19.20 



102. Subtracting the value of the skim milk in each case from 

 the $50 which represents the cosj; of keeping each cow a year, 

 leaves $40.00, $35.58, and $30.80. Dividing these figures so obtained 

 by the pounds of butter produced in each case gives the cost of the 

 butter per pound as 24.9 cents, 14.6 cents, and 9.4 cents. On this 

 basis the cost to the owner of the butter sold from the cow produc- 

 ing 4,000 pounds of milk is nearly 25 cents per pound, the one pro- 

 ducing 6,000 pounds of milk, 15 cents per pcfund, and the one pro- 

 ducing 9,000 pounds of milk, 10 cents per pound. 



103. The difference in the values of the three cows on a butter 

 basis may be shown- in another way. If the butter sells at 25 cents 

 per pound, in each case, then the cow producing 4,000 pounds of 

 milk and 162 pounds of butter pays for her keeping and nothing 

 more. On this basis, all cows giving less than 4,000 pounds of milk 

 per year are kept at a loss to the owner. The cow giving 6,000 

 pounds of milk from which 243 pounds of butter may be made is 

 considerably better than the cow giving 4,000 pounds of milk. 

 Subtracting 162 pounds of butter contained in the milk of the latter, 

 from the 243 pounds of butter of the cow producing 6,000 pounds of 

 milk leaves 81 pounds of butter. If this can be sold at 25 cents per 

 pound it amounts to $20.25. Adding to this, the value of the skim 

 milk in excess of the skim milk contained in the 4,000 pounds of 

 milk produced by the first cow, it would be $14.42 minus $9.60 or 

 about $5, giving a total of about $25.00 as the value of the cow 

 producing 6,000 pounds of milk over that of the cow producing 4,000 

 pounds of milk. A similar calculation of the cow giving 8,000 

 pounds of milk and 324 pounds of butter shows 324 niinus 162 

 pounds of butter equals 162, which at 25 cents per pound amounts 



