56 Animal Husbandry 
It is customary to group together all the substances of a food 
except the water, and to speak of them collectively as dry-matter, 
and not with respect to their total weight. Ash is also eliminated, 
and the remaining three constituents are called nutrients. — 
104. Water. — Water is present in all foods, even the driest. 
It varies widely in different foods, running as low as 8 or 10 per 
cent in the case of grains or concentrates, such as corn, oats, or 
cotton-seed meal, and dried brewers’ grains, to 85 or 90 per cent 
in the more watery foods, as silage, roots, tubers, and the like. 
Even dry hay varies considerably in this respect, alfalfa containing 
as low as 9 per cent and some clovers as high as 20 per cent. Water 
not being a nutrient, its presence or absence is an important 
factor in determining the usefulness and therefore the value of 
food. 
105. Ash.— Ash or mineral matter is present in all plant 
food, although it forms but a small part, shelled corn containing 
only 1.5 per cent, and alfalfa, one of the highest, containing only 
8 per cent. The leaves and the region of the germ in grain contain 
the most ash. The animal secures the ash from the food directly 
by transfer. Most plants contain sufficient ash to meet the needs 
of the animal, corn and certain prepared foods being the only 
exceptions. In young animals, because of the rapid growth of 
bone that is taking place, in milk cows and egg-production hens 
and the like, it is of special importance to have sufficient mineral 
matter supplied by the food. 
106. Protein.— Of the three nutrients — protein, carbohy- 
drates, and fats — the protein is considered to be the most im- 
portant. This is perhaps due to two factors: first, protein is 
absolutely: essential to the animal body, and second, the percentage 
of protein is relatively small in most plants. Like the other 
nutrients, the protein group contains carbon, hydrogen, and 
oxygen, and in addition it also contains nitrogen, which is the 
characteristic element of the entire group. It is on the element 
nitrogen that the importance of this group depends. Protein 
