COMPOSITION OF PLANTS AND FEEDS 389 



Conditions of Growth. The stage of growth, as we have 

 already seen, affects the composition of the plant. Plants grown 

 wide apart give coarser fodder than those sown thickly. Soil and 

 manures also affect the nutritive values of plants, especially in 

 meadows, where acidity or unfavorable soil conditions may 

 promote the growth of plants not well suited for pasturage. 

 Liming and drainage may encourage growth of clovers, vetches, 

 and sweet grasses. Addition of nitrogenous manure may cause 

 increased percentages of protein. Weather conditions also 

 affect the quality of the plants. In wet years, the plant grows 

 larger and is more woody. In dry season, the plant is short and 

 compact. 



Composition of Feeding-Stuffs. The composition of feeding- 

 stuffs shown in the various publications represents the average of 

 variable analyses. 1 The average composition varies with differ- 

 ent sections of the country, and for information in regard to the 

 composition of local feeds, the student should consult the re- 

 ports and Bulletins of his State Experiment Station. Reports of 

 Feed Control officials also show the composition of concentrated 

 feeding stuffs, while the guaranteed analyses are printed on the 

 package, or a tag attached to it. 



Concentrates. The concentrates used in feeding are largely 

 by-products from the manufacture of various articles. These 

 feeding stuffs may be grouped according to their chemical com- 

 position or according to their origin. They are distinguished from 

 roughages by being rich in protein or nitrogen-free extract, and 

 low in crude fiber. 



Classes of Concentrates. Concentrated feeds may be arranged 

 in six groups, according to their content of protein: 



I. Protein 30 to 50 per cent. Cottonseed meal, gluten meal, 

 linseed meal, dried distiller's grains, peanut meal. 



II. Protein 20 to 30 per cent. Malt sprouts, gluten feed, cot- 

 tonseed feed, dried brewers' grain, germ oil meal, whole pressed 

 cottonseed. 



1 Bulletin 11, Office Exp. Sta. 



