412 FEEDING FARM ANIMALS 



Because of the difficulty in obtaining samples, but few 

 analyses of sow's milk have ever been made. At the Wis- 

 consin station the ^average of nine samples gave the fol- 

 lowing in 100 pounds of milk: Dry matter 19.65 pounds, 

 protein 6.4 pounds, carbohydrates 4.75 pounds and ether 

 extract 8.24 pounds. 



The protein is found in the above tables as casein and 

 albumen, the proportions being as about 5 to i. When the 

 casein is coagulated, as by the use of rennet, it forms curd 

 which is made into cheese. The greater portion of the fat 

 also enters into the curd. The albumen does not coag- 

 ulate, and in making cheese, along with the milk sugar, 

 passes into the whey. 



The carbohydrates are formed as milk sugar, which in 

 chemical composition closely resembles cane sugar, but is 

 not equal to the latter in sweetening power, and it is less 

 soluble. It is thought to have about the same feeding 

 value as an equal weight of starch. When milk sours 

 coagulation is caused by some of the milk sugar being 

 changed to lactic acid. 



The ether extract, which is simply fat, exists in the 

 form of minute globules, which are essentially a mixture 

 of several fats. These are exceedingly minute, so much so 

 that their number is almost incredible. When the milk is 

 left at rest, these rise to the surface and form cream. They 

 are also separated by what is known as the centrifugal 

 system, which subjects the milk to a rapid whirling motion, 

 at least soon after it is drawn from the cow. By 

 churning the cream thus gathered, butter is obtained. 



Whole milk is also rich in mineral matter. Were it 

 otherwise, it would not furnish sufficient material for the 

 further development of the bony structure in young ani- 

 mals. Cow's milk contains about seven-tenths of a pound 

 of mineral substance in each 100 pounds of milk, spoken 

 of as ash. It consists chiefly of phosphates and chloride of 

 potash, soda and lime. 



