MILK 



analytical statements of the composition of milk by three prominent 

 analysts are as follows: 



TABLE 3 



Chemical Composition of Skim-milk and Whey. Van Slyke gives 

 the percentage composition of milk skimmed with a separator as: 

 water 90.30, total solids 9.70, butterfat 0.10, casein 2.75, albumin 0.80, 

 sugar 5.25 and ash 0.80. His percentages for whey are: water 93.40, 

 total solids 6.60, butterfat 0.35, casein 0.10, albumin 0.75, sugar 4.80 and 

 ash 0.60. 



The Composition of Milk in Detail. From the average composi- 

 tion of milk it is well to pass to a consideration of its principal compo- 

 nents and the extent to which they may be expected to vary. 



Colostrum. The secretion of milk is preceded by that of colostrum. 

 For a little while before and a short time after parturition the udder 

 yields this fluid which is small in amount, viscous, of a yellow color, a 

 slimy appearance and a pungent taste. Its specific gravity varies from 

 1.046 to 1.079 and its composition, according to Engling is that given in 

 Table 4. 



TABLE 4. THE PERCENTAGE COMPOSITION OF COLOSTRUM (ENGLING) 



Average 



Water. . . 76.60-67.43 71.69 



Fat ,'. . 1.88- 4.68 3.37 



Casein 2.64- 7.14 4.83 



Albumin 11.18-20.21 15.85 



Sugar 1.34- 3.83 2.46 



Ash.. 1.18- 1.23 1.78 



The function of the colostrum is not known. Some are of the opinion 

 that it furnishes nourishment to the newborn calf, not so dissimilar from 

 that it received through the placenta as to make the change in food violent. 

 Others surmise that colostrum starts up digestion in the calf and that it 

 has laxative properties that serve to rid the digestive system of meconium. 



The change from the secretion of colostrum to that of milk is gradual 

 and the time it takes to make it varies with different animals. The 

 nature of the changes is indicated in Table 5. Usually 4 days after 

 calving the milk may be sold as market milk, or be made into butter 

 and cheese, but it often is 2 or 3 weeks before the milk is entirely normal. 



