82 MANUAL OF MILK PRODUCTS 



produces 29 units of yellow in their fat. If this is true, then the 

 following proportion would be a true one, i.e. : 



42 : 29 : : 30 : 18 



The product of the means is not quite equal to the product of the 

 extremes, but gives the result, 



870 = 756 



If the amount of fat produced is taken into consideration and 

 each side of this equation is multiplied by the corresponding 

 amount of fat, we have the result, 



870 X 1.3 = 756 X 1.6 

 or 1131 =1210 



or 1 = 1.07, which is very near unity. 



The relation between the breed of the cow and the color of the 

 fat under two different conditions of feeding is well illustrated 

 by the tables. The color of the fat produced by cows No. 34 

 and 208 is given under both heavy and moderate pigment feed- 

 ing. The data in the second table were obtained a number of 

 weeks after those in the first table. The figures show that the 

 change from heavy to moderate pigment feeding caused the color 

 of the milk-fat of the Jersey cow to drop 50 per cent, while a 

 similar change in the feed of the Holstein cow caused a color drop 

 of only 35 per cent. 



The pigments of the fat from colostrum milk (Palmer and 

 Eckles). 



It is a well-known fact that the first milk drawn after parturi- 

 tion always has a high yellow color. It is not generally known, 

 however, that this high color is usually due entirely to the 

 suspended fat globules. We have many times observed, not 

 only in connection with this study, but also in connection with 

 numerous studies dealing with the chemical composition of milk, 

 that when the fat is entirely removed from colostrum milk the 

 skim milk has the appearance of ordinary skim milk, and the 



