ILLINOIS STATE DAIRYMEN'S ASSOCIATION. 237^ 



Variations in Milk and Milk Productions 



PROFS. E. DAVENPORT AND W. J. ERASER. 



The yield of milk from different cows under the same conditions 

 differs greatly, and that from the isame cow variesi widely from day to- 

 day. 



The composition of milk is highly variable; the ratio of fat to other 

 solids, and that of solids to water, are not constant as between different 

 cows or for the same cow on successive days. 



The percentage of fat, or of other solids, is not always highest in 

 the smaller yields, but cows that give milk with a high per cent of solids 

 generally show a low total yield. 



Fat is the most variable constituent of milk, and its variations are 

 independent of those of the other solids; therefore the yield of milk is 

 a better index of the other solids than it is of the fat. 



As regards the first and last milk drawn, the proportion of solids 

 not fat is higher in the first, but the proportion of fat is decidedly 

 greater in the last. 



When the milking periods are unequal the longer period will gen- 

 erally, though not always, give the larger yield of milk, of fat, and of 

 solids not fat; but the difference in yield does not correspond to the 

 difference in time; that is, the secretion calculated per hour is greater 

 during the shorter period. 



Neither day time nor night time is shown to be superior as a milk_ 

 producing period. 



