FACTORS THAT AFFECT COMPOSITION OF MILK 49 



Daily Variation in Milk and Fat from Individual Cow 



June 30 

 July 1 

 July 1 

 July 1 

 July 2 

 July 2 



Date 



Milking 



P.M. 

 A.M. 



Noon 



P.M. 

 A.M. 



Noon 



Lb. Milk 



3.0 

 12.0 



7.1 



7.6 

 13.2 



6.9 



Per Cent 

 Butter-fat 



2.7 

 3.1 

 3.1 

 3.0 

 6.7 

 4.2 



Lb. 

 Butter-fat 



.083 

 .372 

 .199 



.228 

 .884 

 .290 



Variation of fat-content in different portions of milk drawn from 

 the udder. 

 It is a well-known fact that different portions of the milk 

 drawn from the udder contain varying percentages of fat. The 

 first milk drawn (the fore-milk) normally is very low in fat. 

 As the milking progresses, the fat-content increases till the last 

 portion (the strippings) is reached, which is much richer in fat. 

 This increase between the first and last milk usually amounts 

 to several per cent. The following figures, reported by Van 

 Slyke, 1 illustrate the general rule that the first milk drawn 

 contains least fat, the milk last drawn being the richest 

 in fat: 





Per Cent of Fat in Milk 





Cowl 



Cow 2 



Cow 3 



First portion drawn .... 

 Second portion drawn . . . 

 Third portion drawn .... 

 Fourth portion drawn (strip- 

 pings) 



0.90 

 2.60 

 5.35 



9.80 



1.60 

 3.20 

 4.10 



8.10 



1.60 

 3.25 

 5.00 



8.30 



1 Loc. cit. 



