CARBOHYDRATES AND PAT 35] 



come largely from the protein which these feeds contain in greater 

 abundance than most of the feeds grown on the farm. 



The word "protein"* is used to designate a large number of sub- 

 stances that differ from each other more or less in chemical composi- 

 tion. These substances are alike in one particular — they all contain 

 nitrogen. So the term protein has come to be applied to any nitrog- 

 enous substance, whether animal or vegetable.** 



As far as we are at present able to determine, the proteids of the 

 body are built up only by the animal assimilating the nitrogenous pro- 

 teids already existing in the plant tissues which are consumed in its 

 daily ration. Unlike plants, the animal cannot manufacture its own 

 protein for flesh or milk forming. All it can do is to modify the plant 

 protein and utilize it to form its body tissues, milk solids, and egg 

 albumen. This is why, from the view point of the feeder, protein is 

 such an essential part of corn or any other plant. Besides the part 

 it plays in building up the tissues, protein has a stimulative effect 

 upon the animal functions. It has been found by the Geneva, New 

 York, Experiment Station that protein may be manufactured by the 

 animal into body fat. It may also be used to supply heat and energy 

 to the animal. 



Carbohydrates and Fat.*** All plants contain fat chiefly in the 

 form of vegetable oils. The oils of the corn germ, of linseed, 

 of cotton seed, and the olive, occur in such quantities that they are 

 pressed out or extracted and have a chemical value greater than they 

 would have as feeds for our domestic animals. All plants contain 

 starch (the corn kernel may sometimes contain as high as 70 per 

 cent) ****sugars and vegetable gums. The starches, sugars, and gums 

 are called carbohydrates. The carbohydrates, through a process of 

 oxidation very similar to burning of wood in an engine or stove, sup- 

 ply the energy that the animal requires to masticate, digest, and as- 



*About 16 per cent of most protein substances has been found to consist of nitrogen. In 

 determining the amount of protein present in corn or other grain the amount of nitrogen 

 it contains is iirst obtained, then by multiplying the amount of nitrogen present in the 

 feed by 100-16, or 6 1-4, we obtain an estimate of the protein present. 



**Thus lean meat freed of fat and connective tissue is protein. The white albumen of egg 

 is protein ; so is the gluten of wheat flour. The protein of corn is found principally in the 

 germ and horny gluten, as well as in smaller amounts in the stalk and other portions of 

 the plant. It supplies the flesh forming materials and repairs the wastes of the animal 

 body. It is also one of the indispensable factors in milk production. It is from this 

 substance that the cow makes the casein and albumens for her milk and that the hen 

 manufactures the white albumen for her eggs. 

 ***In determining the percentage of fat, anhydrous ether is used to extract this substance 

 from the water-free plant tissues. Ether dissolves small amounts of vegetable gums 

 and similar substances other than fats; so in the tables of analyses, fats, gums, etc. 

 are classed as "ether extract." In calculations, however, the figures in the columns 

 under "ether extract" may be used as indicating the percentages of fat. In the tables 

 that follow the soluble carbohydrates are found under the heading of ' 'nitrogen free 

 extract." In the analysis of a grain or fodder the nitrogen free extract is determined 

 by difference. That is, in a weighed sample of a grain or fodder the percentage of all 

 of the other constituents, water, ash, protein, fat, and crude fib^r, are first determined 

 and the sum of these subtracted from 100. The difference is called nitrogen free ex- 

 tract or in some tables, carbohydrates. 

 t***rrj,ig starch which is also found largely in the fodder is not affected greatly by cold 

 water, therefore 'ittle of it is carried oft by leaching. 



