New York Agricultuiial Experiment Station:. 89 



(6) Between tlie limits of 3.3 aud 4.2 per eeiit of fat in milk, 

 the amount of cheese made for one pound of fat in milk varied 

 between the limits of 2.80 and 2.60 pounds, which is equivalent 

 to an average decrease of 0.02 pound of cheese for one tenth of 

 a pound of fat in milk. 



1. Milk-Fat as a Basis for Measuring Cheese Production. 



We have seen that, while milk-fat is not an absolutely strict 

 measure of the cheese-producing value of milk, it is in reality a 

 fair and practicable guide in enabling us to learn the relative 

 values of different milks for cheese production. It is probably 

 true more often than not that milk containing three per cent of 

 fat will make somewhat more cheese for a pound of fat than will 

 milk containing four or more per cent of fat. The practical phase 

 of the question which at once presents itself is this: Is the differ- 

 ence in the cheese-producing value of milk poor in fat and milk 

 richer in fat so great as to destroy the value of milk-fat as a basis 

 for measuring cheese i>roduction ? How great a difference can be 

 expected to exist usually? The data secured with 50 separate 

 herds of cows during one factory season enable us to ascertain 

 very closely what average variations exist in the cheese-produc- 

 ing power of milk-fat contained in milks of different composition. 



We find, taking the average of our whole season's work, that, 

 when two milks differ in fat by one per cent, the one containing 

 the smaller amount of fat contains one-tenth more of a pound of 

 casein for a pound of fat than does the richer milk. To illustrate, 

 milk containing 3 per cent of fat usually can be expected to con- 

 tain 2.10 per cent, of casein or 0.70 pounds of casein for one pound 

 of fat; while milk containing 4 per cent of fat will rarely, under 

 normal conditions, contain less than 2.40 per cent of casein or 

 0.60 pounds of casein for one pound of fat. We shall, in our 

 further discussion, use for convenience the limits 3 and 4 per cent 

 of milk-fat. It is important to bring out clearly what makes 

 the difference in relative cheese yield between milk poor in fat 

 and milk rich in fat. 



