CHAPTEE IX. 

 TESTING MILK ON THE FARM. 



155. Variations in milk of single cows. The variations 

 in the tests of milk of single cows from milking to milk- 

 ing or from day to day, are greater than many cow- 

 owners suspect. There seems to be no uniformity in this 

 variation, except that the quality of the milk produced 

 generally improves with the progress of the period of 

 lactation; even this may not be noticeable, however, 

 except when the averages of a number of tests made at 

 different stages during the lactation period are compared 

 with each other. When a cow gives her maximum 

 quantity of milk, shortly after calving, the quality of her 

 milk is generally poorer (by one per cent, of fat, or less) 

 than when she is drying off. Strippers' milk is therefore 

 as a rule richer in fat than the milk of fresh cows. 



156. By testing separately every milking of a number 

 of cows through their whole period of lactation, the 

 results obtained have seemed to warrant the following 

 conclusions in regard to the variations in the test of the 

 milk from single cows, and it is believed that these 

 conclusions allow of generalization. 1 



1. Some cows yield milk that tests about the same at 

 every milking, and generally give a uniform quantity of 

 milk from day to day. 



2. Other cows give milk that varies in an unexplain- 

 able way from one milking to another. Neither the 



i Illinois experiment station, bulletin No. 24. 



