DAIRYING 



percentage of solids-not-fat in the milk serum explains the 

 difference between the skimming efficiency of milk from a fresh 

 and from a stripper cow. Late in the milking period the fat 

 globules are small, and although the milk may be rich as is usual 

 with an old milking cow, the cream does not separate so well as 

 earlier in the milking period, because of the change in size of 

 the fat globules. 



218. Dean reports results from setting milk in cans in ice 

 water in which the skim milk from fresh cows contained .4% fat; 

 at the middle of the milking period, .6% fat; and late in the 

 milking period, .7% fat. Another investigation on the influence 

 of the size of the fat globules on cream separation showed that 

 the richness of the skim milk increases as the number of the 

 small fat globules increased. Each lot of milk was examined 

 with a microscope and graded according to the percentage of 

 fat globules having a diameter of .003 millimeters. These were 

 skimmed with a separator and the following results reported : 



This shows that when only one-third or 33.6 per cent, fat, the 

 skim milk tested about one-half as much as when three-fourths or 

 74.0 per cent, of the fat globules were the diameter mentioned, 

 and the whole milk tested 2.54 per cent. fat. 



