CARE AND FEEDING OP DAIRY CATTLE. 31 



PURCHASING FEEDING-STUFFS. 



The farmer does not need to be a chemist to purchase feeds intelligently. He 

 needs to know the functions of the main constituents of feeding-stuffs protein, fat, 

 carbohydrates, fibre, and ash. Knowing this, and having the analysis before him, 

 he is well able to valuate and compare different feeds. 



PROTEIN. 



This part of a food goes to form the tissues and organs of the body, the blood, 

 hide, hair, horns, and the curd of milk. Lean meat, blood, and the white of eggs 

 are nearly pure protein and water. The main element in protein is nitrogen. 

 Hence we say that the protein is the nitrogenous part of a food. It will be readily 

 seen what an important part protein plays in the growth of the body, the repair 

 of the wear and tear constantly going on in the body, and also in milk production, 

 since milk is a very nitrogenous product. 



CABBOHYDRATES. 



Starch and sugar, made up of carbon, hydrogen, and oxygen, are pure carbo- 

 hydrates. Other similar substances are included under this name. Carbohydrates 

 are used in the animal body to produce heat and energy, and, where plentiful, to 

 produce body-fat as well. 



FATS OR OILS. 



These form body-fat and the fat in milk. Fats or oils also produce heat and 

 energy in the animal body, and for this purpose they have a value two and a quarter 

 times as great as starch or carbohydrates. 



FIBRE. 



This constituent is the least valuable of the nutrients in a food. In composition 

 and function it is similar to carbohydrates, but is of less value to the animal, because 

 more or less of it is indigestible and cannot be used. Moreover, this indigestible 

 part of the fibre has to be moved through the intestines. So that the more indigest- 

 ible or woody fibre a food contains, the less valuable it is. 



ASH. 



This is the mineral matter taken from the soil the crop grew upon. It is 

 composed chiefly of lime, magnesia, potash, and soda, combined with phosphoric 

 and other acids. All the cells of the body contain some mineral matter and the 

 bones are largely phosphate of lime. 



IMPORTANCE OF PROTEIN AND FAT. 



A farmer usually has enough home-grown fodder to supply all the carbohydrates 

 and fibre needed. He usually buys feeding-stuffs for the protein and fat they con- 

 tain, and generally the protein is the most important to him. 



We will suppose that he is offered bran at $1.35 and linseed-meal at $2.10 per 

 100 Ib. He finds from the analysis given in the table that good bran contains 15.4 

 per cent, crude protein and 4 per cent, of fat, a total of 19.4 Ib. of protein and fat 

 in 100 Ib. bran. From the analysis of the linseed-meal (which should be on every 

 sack) he finds that it contains 37.5 per cent, crude protein and 2.7 per cent, fat, 

 or a total of 40.2 Ib. of protein and fat in 100 Ib. linseed-meal. By dividing the 

 price per 100 Ib. by the above totals $1.35 -f- 19.4 and $2.10 -=- 40.2 he arrives at 

 the conclusion that for each pound of protein-fat in bran he must pay 7 cents, while 

 he can buy a pound of protein-fat in linseed-meal at 5 cents, at the above prices. 

 Furthermore, owing t<5 bran containing more indigestible fibre than the linseed-meal, 



