40 BULLETIN 1151, IT. S. DEPARTMENT OF AGRICULTURE. 
KINDS OF FEED. 9 
For maintenance and growth three substances are necessary — pro- 
teins, fats, and carbohydrates. 
Proteins. — Strictly lean meat, from whatever source derived, af- 
fords fuel in the form of protein. The leanest meat is fish. From 
ibones gelatine and pure protein are obtained, the latter, however, 
not in all respects equivalent to that of meat. Milk and eggs are 
particularly valuable for their protein content. Feeds in the protein 
class include horse meat, beef, mutton, veal, pork, rabbit, squirrel, 
chipmunk, woodchuck, chicken, pigeon, various kinds of fish, lobster 
bodies, packing-house offal (such as hearts' livers, spleens, tripe, 
tongues, trimmings, and lungs), eggs, milk (whole, separated, con- 
densed, and evaporated), ground alfalfa, oats, wheat, and corn. 
Fats are found to a greater or lesser extent in all kinds of meat. 
Feeds classed as fats include milk (especially valuable for its fat), 
eggs, suet, cracklings, oil meal, and fish meal. 
Carbohydrates are contained in wheat, oats, corn, and other grains 
and to some extent in all kinds of fruits and vegetables. Feeds 
classed as carbohydrates include bread, cracker waste, shredded 
wheat waste, rice, ground wheat, corn meal, oatmeal, bran, mid- 
dlings, homemade and manufactured biscuits, apples, raisins, grapes, 
onions, and carrots. 
Minerals are most easily supplied in a mixed ration. Feeds con- 
taining iron, calcium, and phosphate are milk, dried blood, tankage, 
fish meal, and ground raw bone. Water, while not strictly a food, 
contains some mineral matter, but its chief functions are to help regu- 
late the concentration of the food elements, making possible the trans- 
portation of various materials to the tissues by holding them in solu- 
tion, and to facilitate the removal of waste through the excretory 
system. 
Aside from the fuel feedstuff's, mineral constituents, and water, 
there are substances existing in minute quantities in some feeds and 
not in others that exercise a profound influence on nutrition. Only 
recently have these been studied, and their exact nature is still under 
investigation. They are spoken of as vitamins, or accessory food 
substances. Fresh i'eeds and whole milk, together with some varia- 
tion from time to time in kinds of feed, will supply these accessories 
in sufficient quantity for all the elements contributing to good 
nutrition to be represented. 
A ration composed of a variety of feeds will give better results 
than a very simple fare, even though trie latter supplies the proper 
proportion of proteins, carbohydrates, fats, and minerals. This 
does not imply changes in the ration from day to day. The meat 
part of the ration especially should be varied as widely as possible. 
Some ranchers feed foxes entirely on meat and, to obtain variety, 
give beef one day. horse meat the next, liver the next, etc. The de- 
sire* I end is not thus attained, for the food constituents are prac- 
tically the same. 
•All the feeds mentioned have been actually fed on ranches in the United States and 
Canada, 
