12 The Bulletin. 



as ths 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. 



Tor 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 fur- 

 nished 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 reason- 

 able limits the standard graces 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*, 

 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 analyses (104 sam- 

 ples) : Protein 15.38 per cent; fat 4.63 per cent; fiber 8.30 per cent; 

 nitrogen-free extract 55.08 per cent; water 9.87 per cent; ash 6.74 per 

 cent. 



Winter Wheat Bran. — Analysis: Protein 15.87 per cent; fat 4.72 per 

 cent; fiber 8.45 per cent; nitrogen-free extract 55.60 per cent; water 

 8.43 per cent; ash 6.93 per cent. 



Spring Wheat Bran. — Anaylsis : Protein 14.62 per cent ; fat 5.43 per 

 cent; fiber 11.15 per cent; nitrogen-free extract 54.26 per cent; water 



8.51 per cent; ash 6.03 per cent. 



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

 ably in the trade and are used to describe the various products interme- 

 diate between bran and flour, some being composed largely of starchy 

 matter, while others contain more of the fibrous tissues of the grain. 



Average analysis (99 samples) of goods sold under the name mid- 

 dlings or shorts: Protein 16.84 per cent; fat 5.07 per cent; fiber 5.66 

 per cent ; nitrogen-free extract 58.44 per cent ; water 9.47 per cent ; ash 



4.52 per cent. 



In addition to the products sold under the general terms of middlings, 

 shorts or standard 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. 



•The analyses used in these descriptions marked (f) are taken from Bulletin No. 11, Office of 

 Experiment Stations, U. S. Department of Agriculture. Those not so marked are compiled from 

 analyses made in this laboratory. 



