The Bulletin. 13 



dition, and as this destroys the characteristic appearance of the 

 ingredients it is very easy to adulterate them with finely ground 

 rice chaff, corncobs or peanut hulls. All of these substances have 

 characteristic elements which are readily distinguished under the 

 microscope. 



For example, if a mixed feed contains 15 per cent of fiber it would 

 not be considered low grade, provided it is made from good materials ; 

 but if the microscopic examination shows that part of this fiber 

 is furnished by rice chaff or corncobs it would be considered a very 

 low-grade feed. 



DESCRIPTION AND COMPOSITION OF THE BY-PRODUCTS USED 



FOR FEED. 



The materials used for commercial feeds are usually the by- 

 products of other industries, such as the by-products from flour mills, 

 oil mills, etc. The composition of these materials varies somewhat 

 with the season in which they are grown, the method of milling, 

 etc.; but within reasonable limits the standard grades of these by- 

 products have a very similar composition. The following general 

 descriptions of these products, with the average analyses, compiled 

 from a large number of analyses 1 , will show what the compositions 

 of each one of these products should be. 



WHEAT PRODUCTS. 



Bran. — This consists of the outer portion or covering of the wheat 

 grain. It contains the greater portion of the fibrous material of the 

 grain, but is also rich in protein and fat. Average analysis : Protein, 

 15.03 per cent; fat, 4.52 per cent; fiber, 8.36 per cent; nitrogen-free 

 extract, 56.15 per cent; water, 9.33 per cent; ash, 6.61 per cent. 



Middlings or Shorts. — These terms are used, generally, inter- 

 changeably in the trade and are used to describe the various products 

 intermediate between bran and flour, some being composed largely 

 of the starchy matter, while others contain more of the fibrous tissue 

 of the grain. 



Average analysis of goods sold under the name middlings or shorts : 

 Protein, 16.53 per cent; fat, 5.04 per cent; fiber, 5.50 per cent; 

 nitrogen-free extract, 59.90 per cent; water, 8.79 per cent; ash, 4.24 

 per cent. 



In addition to the products sold under the general term middlings, 

 the following grades of middlings are made, depending on the process 

 of milling and the parts of the grain of which they are composed: 



Standard Middlings. — Average analysis: Protein, 16.54 per cent; 

 fat, 5.63 per cent; fiber, 7.28 per cent; nitrogen-free extract, 56.41 

 per cent; water, 9.21 per cent; ash, 4.93 per cent. 



»The analyses used in these descriptions marked (t) are taken from Bulletin No. 11, Office 

 of Experiment Stations, U. S. Department of Agriculture. Those not so marked are com- 

 piled from analyses made in this laboratory. 



