CHAPTER IX. 

 TESTING MILK ON THE FARM. 



159. Variations in milk of single cows. The varia- 

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

 milking 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 maxi- 

 mum quantity of milk, shortly after calving, the qual- 

 ity of lier 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. 



160. 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 con- 

 clusions allow of generalization.^ 



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. 



* Illinois experiment str.tlon, bulletin 24. 



