ROOTS, TUBERS, AND OTHER SUCCULENT FEEDS 137 
red or yellow varieties impart a rich color to the milk, owing to the 
coloring matter (carotin) which they contain, and produce a yellow 
cream and butter, making the use of artificial coloring in butter- 
making quite unnecessary. Stock carrots will yield 10 to 20 tons 
per acre, according to the character of the soil, or still more under 
favorable conditions.. They contain, on the average, about 12 per 
cent of dry matter, of which the greater portion is sugar (sucrose 
and glucose). They may be used to replace a portion of the oats 
in the ration of horses that are hard worked, feeding about six to 
eight pounds per head daily. 
Potatoes (Solanum tuberosum) are used extensively for stock 
feeding by European farmers, but only to a small extent in this 
country. The growing of this crop for the purpose of furnishing 
feed for farm animals cannot be recommended, on account of the 
relatively low yields obtained (average, 200 bushels at 60 pounds, 
or six tons) and the expense of production; but on most farms a 
supply of cull potatoes is available, and in potato-growing districts 
large amounts of such potatoes may be profitably used for feeding 
farm animals. 
Potatoes are primarily a fattening feed and are used especially 
.. for feeding swine. ‘They may also be fed to advantage to other 
classes of stock,—horses, wethers, and milch cows, as a partial 
substitute for grain. ‘They are generally cooked for swine, and are 
fed sliced, mixed with grain feed, to other classes of farm animals. 
Potatoes contain about 20 per cent of dry matter, of which over 
80 per cent is composed of carbohydrates, largely starch. Like all 
roots and tubers, they are low in fat; the high starch content places 
them among our foremost starchy feeds and renders them especially 
valuable for fattening purposes. Danish feeding experiments have 
shown that four pounds of boiled potatoes are equal to a pound of 
mixed grain for feeding swine, and that for dairy cows it takes 
six pounds of raw potatoes to equal a pound of mixed grain (1 feed 
unit, p. 79). 
Unripe potatoes contain a poisonous nitrogenous compound 
called solanin, which also accumulates in considerable quantities in 
the sprouts; in feeding old sprouted potatoes the sprouts must, 
therefore, be carefully removed to prevent accidents. 
During recent years machinery for drying potatoes has been 
greatly perfectéd in Germany, and dried potatoes in the form of 
flakes or chips are now a regular article of commerce in Europe. 
It takes, on the average, about 3.8 tons of raw potatoes to make 
a ton of dried potato flakes. These are pronounced “much cheaper 
