8 PRINCIPLES OF FEEDING FARM ANIMALS 
in the soil where the plant grew. The elements found in the mineral 
matter are present in one or two forms: Hither in inorganic form, 
in combinations of two or more of the elements, as sulfates, phos- 
phates, nitrates, chlorides, or silicates, combined with bases, as 
_ potassium, sodium, calcium, magnesium, and iron; or in organic 
form, as constituents of organic compounds. Especially in the case 
of seeds of plants the ash materials are present largely in the 
latter form. 
_ Ordinary feeding stuffs contain, as a rule, only relatively small 
amounts of mineral matter, viz.: Less than 5 per cent, except in 
the case-of some factory by-products and dry forage, in which 
the ash content may go even above 10 per cent. Leafy plants con- 
10 20 30 40 50 60 70 8 90 100 HO 120 130 140 150 160 170 180 
ALFALFA HAY 
COTTON-SEED MEAL 
CLOVER HAY 
WHEAT BRAN 
LINSEED MEAL 
DRIED BEET PULP 
TIMOTHY HAY 
DRIED BREWERS’ GRAINS 
OATS” 
CORN 
6LUTEN FEED 
POTATOES 
SE RSE SS RE RO 
2 Se ee 
a a 
(SN A 
Fra. 2.—Mineral matter in a ton of common feeds, in pounds. 
tain relatively large percentages of ash, like all parts of plants in 
which a considerable evaporation of water takes place. On the 
other hand, by-products in manufacturing processes where the raw 
materials are treated with large quantities of water, as gluten feed, 
brewers’ grains, etc., have comparatively small ash contents (Fig. 2). 
Protein is a general name for nitrogenous organic compounds 
of a very complex chemical structure. They contain carbon; oxygen, 
hydrogen, and nitrogen, with a small percentage of sulfur and, in 
some cases, phosphorus. The name protein was given to these sub- 
stances by Mulder, a German chemist, and means the first or the 
most important. This term is justified from a physiological point 
of view, inasmuch as protein is absolutely essential to animal life. 
The protein substances are characterized by the fact that all 
contain the element nitrogen, which is not found in the other groups 
