586 NUTRITION OF FARM ANIMALS 



plant growth, containing a high percentage of nitrogen, much of 

 it in the form of non-protein, and a low percentage of crude fiber. 



Brewers' grains. The next step in the process is the mash- 

 ing of the ground malt and other grain with warm water. In 

 this process, the diastase of the sprouted barley acts on the 

 starch of the grain, transforming it into sugar. In the manu- 

 facture of beer or ale, the resulting liquid is drawn off and fer- 

 mented separately, leaving a residue known as brewers' grains, 

 which is used extensively as a dairy feed. In the fresh state it 

 is valuable, but is subject to the disadvantage of fermenting or 

 souring very readily, and tending in this state to injure the 

 quality of the milk. Somewhat recently, economical pro- 

 cesses for drying it have been perfected, and the dried brewers' 

 grains constitute a valuable feed which can be shipped like 

 any other dried feed. 



Distillers' grains. In the preparation of distilled liquor or 

 alcohol, the liquid is fermented in contact with the grains and 

 the alcohol then distilled off, leaving a residue known as dis- 

 tillers' grains or distillery slop. This residue is much wetter 

 than brewers' grains, but is less subject to fermentation, since 

 the sugar has been more completely removed. Large quantities 

 of it are now put on the market in the dried form, both under 

 its own name and various trade names, some of which contain 

 no suggestion of the real nature of the material. It constitutes 

 a valuable source of stock feed. The grains produced from rye 

 are regarded as the poorest and those from maize as of the best 

 quality. 



In all these processes the object is to convert the starch of 

 the grain as completely as possible into sugar and then into 

 alcohol. This results in increasing the percentage of all the other 

 ingredients in the residues. They contain accordingly a high 

 percentage of protein with also a somewhat greater percentage 

 of crude fiber than the ordinary grains. They serve, therefore, 

 not only to supply digestible matter as a whole but also to 

 correct a deficiency of protein in the ration. 



696. By-products of oil extraction. The extraction of com- 

 mercial oils from various oil-bearing seeds leaves by-products, 

 called oil cake or oil meal, some of which have a high feeding 

 value. Of these, cottonseed and linseed meal are the only ones 

 extensively used in the United States and are typical of the 



