4 N. H. EXPERIMENT STATION [Bulletin 209 



WHAT DOES THE CHEMICAL ANALYSIS MEAN? 



In a feed analysis the following determinations are 

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

 and crude fiber. 



Protein is determined by finding the percentage of total 

 nitrogen and multiplying this by the factor 6,25, since it 

 has been found that the average proteins contain 16 per 

 cent, nitrogen. While this includes small amounts of cer- 

 tain other compounds which contain nitrogen, for all prac- 

 tical purposes it is sufficiently accurate. Protein, then, is 

 made up of the compounds in the feed which contain nit- 

 rogen. 



Fat is determined by extracting a dried sample of the 

 feeding-stuif with ether and weighing the residue after the 

 ether is driven off. In main it contains the vegetable fats 

 of which olive oil, linseed oil, and cottonseed oil are ex- 

 amples. It contains also small amounts of chlorophyll, (the 

 green coloring matter of the leaves), waxes, resins, etc.; 

 but for practical purposes it is accurate enough to deal 

 with it as fat. 



Ash is determined by weighing the residue after the 

 feeding-stuff has been burned at a low temperature. It 

 contains the mineral matter of feeding-stuffs. 



Moisture is determined by finding the loss in weight 

 after heating at the temperature of boiling water. It 

 shows the amount of water that the feed contains. 



Carbohydrates are determined by adding the percent- 

 ages of the protein, fat, moisture and ash, and subtract- 

 ing 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. 



