6 N. H. EXPERIMENT STATION [Bulletin 218 



THE CHEMICAL ANALYSIS 



In a feed analysis the following determinations are 

 usually made: protein, fat, carbohydrates, ash, moisture 

 and crude fiber. 



Protein is a term employed to designate the compounds 

 in feeding-stuffs which contain nitrogen. It is determined 

 by finding the per cent, of nitrogen and multiplying by the 

 factor 6.25 since it has been found that most proteins con- 

 tain approximately 16 per cent, nitrogen. 



Fat is determined by extracting a dried sample of the 

 feeding-stuff with dry ether and weighing the residue after 

 the ether is evaporated. It contains the vegetable fats of 

 which linseed oil, and cottonseed oil are examples. The 

 ether extract contains also small amounts of chlorophyll, 

 (the green coloring matter of the leaves,) waxes, resins, 

 etc. 



Ash is determined by weighing the residue after the 

 sample has been burned at a low temperature. It contains 

 the mineral matter of feeding-stuffs. 



Carbohydrates are determined by adding the percent- 

 ages of protein, fat, moisture and ash, and subtracting the 

 total from 100 per cent. The carbohydrates are composed 

 largely of starches, sugars, pentosans, celluloses, etc. The 

 carbohydrates include the crude fiber also. The percentage 

 of carbohydrates less the percentage of crude fiber is called 

 nitrogen free extract. 



Crude Fiber is made up of the more wood-like carbo- 

 hydrates which are largely of a cellulose nature. Pure cot- 

 ton is an example of almost pure cellulose. Wood, straw, 

 corn fodder, etc., are materials which are high in crude 

 fiber content. 



