ANALYSIS 23 



gives the percentage of water. The dry part of the sample 

 is then burned. Mineral matter will not burn. The ash 

 remaining therefore represents the amount of mineral 

 matter. 



As already indicated, the protein is found by first deter- 

 mining the nitrogen and multiplying it by 6.25. Since 

 about 16 per cent of protein is nitrogen, the weight of pro- 

 tein is 6.25 times the weight of nitrogen. 



Another sample of the feeding stuff is next treated with 

 dilute acids and alkalies to remove all soluble portions. The 

 insoluble part remaining is called crude fiber. It is com- 

 posed chiefly of cellulose, abundant in seed coats, hulls, 

 husks, and stems of plants. Crude fiber is largely in- 

 digestible. Feeds that are high in crude fiber and low in 

 the more soluble nutrients are called roughages. Those 

 comparatively low in crude fiber and high in the other 

 nutrients are called concentrates. 



Another sample is treated with ether. The portion 

 soluble in ether is considered as fat although the term ether 

 extract is to be preferred, because ether dissolves waxes, 

 resins, and gums as well as fat. Waxes, gums, and resins 

 are more abundant in roughage than in concentrates, hence 

 the ether extract of roughage is less valuable than that of 

 concentrates. Fat is very valuable as a nutrient. 



Sugars and starches are included under the term nitrogen 

 free extract. The sum of the ash, fat, protein, and crude 

 fiber is subtracted from the total dry matter. The differ- 

 ence is the nitrogen free extract. The sum of the nitrogen 

 free extract and the crude fiber makes up the carbohy- 

 drates of the feeding stuff. 



An analysis of corn and timothy hay will serve to illus- 

 trate the varying amounts of the different nutrients. 



