VALUE OF TESTS 387 



ware should be washed thoroughly as soon as the test is 

 completed. 



286. The Value of Testing Milk. A farmer cannot tell 

 accurately the richness of a cow's milk unless he uses the 

 Babcock test. He is much more likely to be wrong in a 

 guess than even when he " guesses " about the quantity of 

 milk. The amount of cream on the milk is not a safe 

 guide, because some cream contains twice the butter fat 

 that is found in other cream seemingly as rich. Cows, 

 even of the same breed, differ widely in the amount of fat 

 in the milk. We have spoken above of the need of weigh- 

 ing each cow's milk, to know how much she gives. It is 

 equally needful to test each cow's milk occasionally, or to 

 have it tested at the creamery or school, to know what 

 kind of milk she gives. 



If a cow in a herd gives 6000 pounds of milk in a year, 

 she is pretty sure to be considered a very good cow. 

 Her milk, however, may test only 3 per cent for butter 

 fat. Another cow giving only 4000 pounds may test 

 5 per cent. The second is decidedly the more profitable 

 cow. 



The farmer, then, who uses the scales for quantity, and 

 the Babcock test for quality, can tell which of his cows 

 pay for their keep, and which are "boarders" and cost 

 more than tljey return to the milk pail. Many a farmer, 

 by adopting these devices, has learned that he has been 

 paying for the privilege of milking some of his cows 

 700 times a year. Weighing and testing make it possible 

 to weed out the poor cows and to select the good ones 

 wisely. And weeding ranks with breeding and feeding in 

 the work of grading up the herd. 



287. Testing has a Value also for the Farmer's Patrons. 

 The buyer of milk has a sure means of protecting himself 

 against skimming or watering by the milkman. Cities, 



