Corn Proteins.-The proteins of Indian corn, according to Osborne, are composed of about 10 per cent zein (a characteristic alcohol-soluble protein), 30 per cent glutelin, 22 per cent albumen, globulin and proteose, and 6 per cent protein insoluble in alkali.? While little is known so far regarding the specific nutritive properties of the different protein substances, it seems evident that the special corn proteins possess important advantages over those of the wheat or the oat plant. Investigations conducted during a series of years at the Wisconsin station have shown that corn is the only one of the three cereals which can properly nourish dairy cows for long periods and keep them in a strong, healthy condition so that they will yield a normal production and give birth to normally-developed, vigorous calves.” It has not been established that this difference in the nutritive effects of the three plants fed by themselves is due to differences in the composition of the protein compounds, but, with our present incomplete knowledge of this subject, it seems most likely that the phenomena brought to light in the important investigations referred to are in some way connected with the differences in the amino-acids making up the proteins in these crops.3a

Oats are a highly-prized feed for farm animals, especially horses cows, sheep and young stock. Next to corn, they are the most important cereal for feeding livestock in the l'nited States. Their cost frequently makes them rather expensive for feeding other stock than horses, but, when not too costly, there is no better concentrated feed for the animals mentioned. Oats vary greatly in their percentage of hulls; a good quality of oats contain, on the average, about 30 per cent hulls, while light oats may contain considerably over 40 per cent hulls (or 16 per cent fiber). Oats contain more fiber and protein and nearly as much fat as Indian corn, as will be seen from the analyses given below:

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* Science, 1913, p. 185; Jr. Biol. Chem., 1913, xxxi, No. 2; Proc. Soc. Prom. Agr. Sc., 1914, p. 24.

The hulls serve a similar purpose as corn cobs in grinding the grain, making the meal lighter and more easily digested. Oats are generally fed whole, however, except in the case of old or very young animals that cannot masticate their feed thoroughly. Ground or rolled oats are to be preferred for feeding such animals. The favorable effect of oats on horses has long been known, and it has been held that no other grain or feed is equal to oats for them. It has been stated by various scientists that oats contain a special stimulating principle not found in other grains, but the matter has not yet been fully settled. In 1883 Sanson, a French chemist, claimed to have discovered a characteristic nitrogenous alkaloid in oats called “avenin," having a stimulating effect on the motor nerves of the horse, but subsequent investigators have been unable to verify the presence of such a compound. The careful and exhaustive studies by Osborne have shown that the proteins of the oat kernels are made up of glutenin (about 11 per cent) and a small amount of a globulin called avenalin (1.5 per cent). It is very likely that the digestive ferments found in oats are of importance in the digestion of this grain. The mechanical effect of oats in inciting a free flow of digestive juices may also be a factor in bringing about the favorable results which oats doubtless produce in the feeding of horses.

New oats must be fed with care to horses, as they have a decided loosening effect on the bowels. The change in this respect that takes place in oats in storage also, in all probability, comes as a result of the action of the oat enzymes on some of the constituents of the oats.*

Digestibility of Oats.—The following summary of digestion coefficients shows the extent to which the different classes of farm animals can digest oats:

Horses are evidently able to digest the dry matter of oats, as well as the protein and nitrogen-free extract, better than do ruminants, while these animals digest the fiber and fat better than do horses.

Oats do not have quite as high digestibility as Indian corn, so far as fiber and nitrogen-free extract are concerned, due to the higher percentage and the more woody character of the fiber in oats than in corn. The coefficients for protein and fat in the two grains, on the other hand, are about similar. The high fat contents of these two grains are doubtless important factors in making them palatable stock feeds. Oats, as a rule, have a somewhat lower feeding value than corn, although this depends largely on the combination in which they are fed. In general, a mixture of the two grains gives better results than either fed alone. This rule does not hold good, however, in the case of oats for horses (p. 287).

Corn and Oats (“ Ground feed ”).-Mixtures of corn and oats are ground together and sold in immense quantities in eastern and central States as “ground feed” or “ground corn and oats.” This is used for feeding horses and dairy cows, especially the former, for which purpose it is well adapted. A good grade of corn and oats

A makes a valuable horse feed, but low-grade materials, like oat hulls, refuse from oatmeal factories, ground corn cobs, etc., are often added in making the feed, and its purchase cannot be recommended outside of States which have feed inspection laws on their statute-books, where the feed may be bought on definite guarantees of protein, fat, and maximum fiber contents. The wholesome effect of feed inspection laws has been strikingly illustrated in the quality of the ground feed sold in a State before and after the passage of such protective laws."

Ground oats and corn are generally sold on a guarantee of 9 to 10 per

cent protein, 3 to 4 per cent fat, and 7 to 9 per cent maximum fiber, according to the proportions of the two grains entering into the feed. These may vary from one of corn to three of oats, hy weight, to three of corn and one of oats. The market price of the two grains determine largely the proportions used of each, more corn being used when this grain is the cheaper, and vice versa. Since corn contains only about 2 per cent fiber, and oats, on the average, about 10 per cent, mixtures of the two grains will not be likely to contain over 7 per cent fiber. A fiber content of over 9 per cent is evidence that the ground feed is either adulterated, or that a very poor grade of light oats was used in its manufacture.

Barley is mainly used for stock feeding on the Pacific coast in * Wisconsin Circular 30, p. 83, January, 1912.

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this country, but in middle and northern Europe it is one of the common grain feeds for farm animals. It makes an excellent feed for horses and dairy cows, and, fed with dairy by-products, produces a fine quality of pork. It is generally fed ground, cracked, or rolled. The last method of preparation is considered preferable, because fine-ground barley forms a pasty mass in the mouth of animals and is more likely to give rise to digestive troubles than when rolled, as is the case with fine-ground corn or corn and oats for horses. There is a prejudice among some farmers against feeding barley to milch cows, but this is doubtless unfounded, for its value for milk production has been fully established. In an experiment at the California University Farm a cow that received green alfalfa or alfalfa hay and only rolled barley in addition, 10 pounds daily as a maximum feed, produced an average of 60 pounds of milk for over three months, and not only did better on this feed, but kept up better in her milk flow than during any previous lactation period.

Barley is higher in protein and carbohydrates than oats, and lower in fat, containing, on the average, 12.0 per cent protein, 1.8 per cent fat, 4.2 per cent fiber, 68.7 per cent nitrogen-free extract, and 2.5 per cent ash. It has a high digestibility.

Percentage Digestibility of Barley

While it is considered that rain or foggy weather during ripening injures the quality of barley for brewing, this does not affect its feeding value in any way, and barley unfit for brewing can often be obtained for feeding purposes at a low figure.

Rye is less used for stock feeding in America than the three cereal grains considered in the preceding. Its value for this purpose is, however, well established. It is the common bread grain in northern Europe, and is also fed to stock when its price is not too high. Rye does not differ greatly from barley in the composition or feeding value. Its average composition is: 11.3 per cent protein, 1.9 per cent fat, 1.5 per cent fiber, 74.5 per cent nitrogen-free extract, and 2.1 per cent ash. Its average digestion coefficients, as determined with cows, are: Protein, 80 per cent; fat, 86 per cent, and nitrogen-free extract, 80 per cent.

Report 1914-15, p. 33; See Farmers' Bul, 968; Jr. Biol. Chem. 35, p. 61.

Rye makes a valuable feed for horses and fattening swine; it is often fed soaked to the latter farm animals, and is preferably fed ground and mixed with other concentrates to other classes of livestock. Rye was found to have about the same feeding value as barley in extensive Danish swine-feeding experiments, and the quality of the pork produced was satisfactory. The best results were, however, obtained with mixtures of the two cereals.

Wheat is too high-priced, as a general rule, to be used for feeding farm animals. In exceptional cases it may be advisable to use it for this purpose, however, and it is well, therefore, to understand its nutritive value and main characteristics, especially since the lower grades of wheat can generally be used for stock feeding to advantage, even at present-day market prices for grains.

Wheat stands close to barley in composition and feeding value. It is of slightly lower value as a feed for fattening animals, but is superior to this cereal in nutritive effect for young and growing animals and for dairy cows. It is lower in fat but somewhat higher in protein and carbohydrates than corn; its digestibility is as high as that of the other cereals except oats, which, as stated, have a somewhat lower digestibility than these on account of their relatively high fiber content.

Wheat is generally ground before feeding. On account of its large content of gliadin and glutenin, it forms a sticky paste when chewed, and for this reason is preferably fed in mixtures with more bulky concentrates, like oats or wheat bran.

Damaged wheat (salvage wheat from elevator fires, etc.) is at times obtainable at a low cost; the better grades make a valuable feed, only slightly inferior to an average grade of wheat.

Grain screenings are mixtures of broken or shrunken grain, weed seeds, chaff, pieces of straw, dirt, etc., which are obtained in the cleaning of grain in elevators. They vary considerably in their chemical composition and feeding value, according to their origin and the character of the impurities contained in the grain. On account of the large proportion of different weed seeds in screenings, they are expensive feeds at any price to farmers who wish to keep their land as free as possible from noxious weeds. Many of the weed seeds in screenings will pass through the animals uninjured and will germinate when the manure is put on the land, thus rendering cultivation more expensive and reducing the yield of cultivated crops through the growth of weeds. Many farmers do not, therefore, wish to buy screenings under any condition, and this

? Vermont Bulletins 131 and 138.