322 



COLOSTRUM INFLUENCE OF BREED 



contains less of the volatile fatty acids than ordinary milk fat. The 

 sugar present is largely grape sugar. Urea has been found in colos- 

 trum. The ash differs from that of normal milk in the smaller amount 

 of potash and the much larger quantity of phosphorus pentoxide (up 

 to 41*4 per cent). The liquid secreted by a cow gradually changes, 

 day by day, until in four or five days it approaches normal milk in 

 composition, though the " colostrum granules " can be detected in the 

 milk for fourteen days or more after calving. The rapidity with which 

 colostrum gradually passes into normal milk is well shown by the 

 following analyses by Bugling : 



Variations in Composition. 



Influence of breed. Great variations, especially in the . proportion 

 of fat, are shown by the milks of different races. The following 

 numbers were obtained at the New York Experiment Station in 1891 1 : 



AVERAGE COMPOSITION OF MILK. 



Vieth 2 gives the following averages : 



1 Vide Report of Director, p. 141. 



2 Quoted by Richmond, Dairy Chemistry, p. 125. 



