332 ILLINOIS STATE DAIRYMEN'S ASSOCIATION 



6. Changing the rate of inflow of milk into the separator 

 bowl. 



Richness of the Milk Separated. Other conditions being the 

 same the richer the milk that is separated the higher will be the 

 butter fat test of the cream. At a given speed a certain amount 

 of cream will pass through the cream outlet of the separator. If 

 the milk is poor in butterfat there will be less fat in the cream 

 and consequently it will have a lower test than if the milk is rich 

 in fat. The more fat in the milk the heavier will be the cream if 

 the speed is the same. As the quantity of cream does not change, 

 when the amount of fat increases it must raise the test of the 

 cream. 



Dairymen who are fortunate enough to be members of a 

 cow-testing association have soon learned, if they did not know 

 it before ,that milk is subject to more or less frequent change in 

 butterfat, depending upon certain conditions. 



1. When a cow is excited by rough treatment either by 

 the milker or by being chased by dogs she will give less butterfat 

 in her milk; consequently her test will drop; the same cause will, 

 of course, produce the same result in a whole herd. 



2. As the lactation period advances, other conditions being 

 normal, the test goes up. 



3. Sudden change of feed, as from dry feed to grass in 

 spring, will cause a drop in the milk test. Any one or all these 

 causes will be sure to raise or lower the cream test as the test of 

 the milk goes up or down. 



Changing Speed of Separator. Increasing the speed of the 

 separator forces out a large quantity of skimmilk; therefore 

 there will be a smaller amount of cream and it will be richer in 

 butterfat. Likewise reducing the speed of the separator in- 

 creases the amount of cream and lowers its test. Care must be 

 taken to keep the speed up to the proper point and keep the speed 

 uniform. A little carelessness in this matter will cause such sur- 

 prising variations in the cream test that the patrons should be 

 better able to explain than the creamery buttermaker, who has 

 no way of knowing how the separator was handled. 



