THE FEEDING STUFFS 



573 



fat is small and includes much besides true fat. The nitrogen- 

 free extract, along with more or less starch and sugar, includes a 

 great variety of less familiar carbohydrates and of other sub- 

 stances whose nutritive value is problematical. By far the 

 larger proportion of the roughages in common use is supplied 

 by two classes of plants, the grasses (Gramineae), including 

 maize, and the legumes (Leguminosae). Furthermore, crops 

 belonging to both these classes may be used for fodder when 

 but partially mature (hay, maize forage), or they may be al- 

 lowed to ripen, the grain may be removed, and the residue 

 (straw, stover) used for feeding. 



679. The grasses. The larger share of the hay crop and 

 of the pasturage of the United States is supplied by plants known 

 in a restricted and popular sense as grasses, such as timothy, 

 blue-grass, red- top. To these must be added, as a most impor- 

 tant source of forage in the United States, maize, or Indian 

 corn, which botanically is a grass, although not commonly so 

 called. The forage supplied by these plants has a very wide 

 range of nutritive value, depending on a variety of conditions. 

 Chief among these is the stage of maturity at which the crop 

 is utilized. In young, growing vegetation the cell walls are 

 thin and consist of nearly pure cellulose, while the cells are 

 filled with active protoplasm whose chief ingredients are pro- 

 teins. Hence, forage cut at this stage shows a relatively low 

 percentage of crude fiber and a high percentage of proteins. 

 Young and tender pasture grass, relatively rich in protein and 

 low in crude fiber, may even approach the concentrates in value, 

 as illustrated by the following comparison of the dry matter of 

 a sample of young pasture grass with that of average oats : 



TABLE 162. COMPARISON OF PASTURE GRASS AND OATS 



