6 PRINCIPLES OF FEEDING FARM ANIMALS 
whose exact composition has not yet been ascertained. For our 
present purpose they may, however, be conveniently considered as 
belonging to a few groups of substances which can be readily deter- 
mined by chemists. These groups of components are separated in 
the customary chemical analysis of feeding stuffs, and the per- 
centage quantities present in each are ascertained. For the pur- 
poses of chemical analysis and for our discussions we may thus 
consider plant materials composed of— 
I. Water. 
II. Dry substance. 
The dry substance of plants is of either (1) mineral or (2) so- 
called organic origin. The former components are known as 
mineral matter or ash; while the organic matter is composed of 
the following groups of substances: Protein, fat, nitrogen-free 
extract, and fiber. The last two belong to a group of substances 
known as carbohydrates. 
The schedule given below will help to make clear these various 
groups of plant components: 
Plants contain— Composed of the elements 
Ty Water sc. sacsantg ccawlasieien $44:6.6.0:66 0 Oxygen, hydrogen. 
Potassium, sodium, calcium, 
magnesium, sulfur, chlo- 
rin, iron, phosphorus, 
silicon, etc. 
II. Dry substance: 1. Mineral matter (ash) 
Carbon, oxygen, hydrogen, 
2. Protein............ | nitrogen, sulfur (and 
sometimes phosphorus). 
Be Fates cca ste x ees 
4. Nitrogen-free exact} Carbon, oxygen, hydrogen. 
5. Fiber.............. 
COMPOSITION OF PLANTS 
Water is found in all plants and plant materials, ranging in 
amount from 5 per cent to 95 per cent in extreme cases. Some 
factory by-products which have been artificially dried contain less 
than 10 per cent, in some cases as low as 5 per cent of water. Hay: 
and dry coarse feeds generally contain from 10 to 20 per cent, 
while corn fodder (stover) and some kinds of hay, as alfalfa, will 
occasionally contain as much as 30 per cent of water when im- 
perfectly cured or exposed to damp or rainy weather. The cereals 
and most concentrated feeds contain about 12 per cent water ; 
green forage crops from 70 to 90 per cent; silage, 70 to 80 per 
