THE FEEDING STUFFS 579 



bohydrates, whose exact nutritive value is still uncertain. 

 There are also present in roots, and particularly in fruits, 

 more or less organic acids whose nutritive value is low. In 

 consequence of their succulent and tender nature, tubers, and 

 especially roots, have a high degree of digestibility and may be 

 presumed to require little energy for their digestion. They 

 are therefore a valuable source of carbohydrate material, even 

 though some of their ingredients are of somewhat inferior 

 value. In general, the dry matter of tubers is more valuable 

 than that of roots. On the other hand, the dietetic effects of 

 roots are especially prized, but the considerable amount of labor 

 required for their cultivation tends to restrict their use. 



3. THE CONCENTRATES 



686. Comparison with roughage and with roots. The con- 

 centrated feeding stuffs, or " concentrates," as their name im- 

 plies, are those which contain a large amount of nutriment in 

 a small weight and bulk. They stand in contrast, on the one 

 hand, with roughage, in which the real nutriment is accom- 

 panied by a large proportion of woody fiber and other indiges- 

 tible matter which adds to the weight and bulk without mate- 

 rially increasing the nutritive value. On the other hand, they 

 excel the roots and tubers because, while the dry matter of the 

 latter is very valuable, it is largely diluted, so to speak, with 

 water. The concentrates are therefore the main reliance for 

 the rapid, intensive production of meat, milk or work. The 

 concentrates may be subdivided into farm products and the 

 by-product feeding stuffs. 



Farm products 



687. The cereal grains. The grains were, until compar- 

 atively recent times, the main reliance of users of concentrates, 

 and indeed are still in many sections of the United States. 

 Corn, oats, barley, rye, peas, beans, rice and at times even 

 wheat, are feeding stuffs whose value needs no advocate. These 

 seeds contain, stored away for the use of the young plantlet, 

 proteins, fats and carbohydrates of the most valuable character 

 and " representing the highest type of vegetable food." Their 



