Aug., 1924] inspection of feeding stuffs 5 



More feeds were deficient in protein and fat this year than 

 in any of the past four years. The compounded feeds, cotton- 

 seed meals, dairy feeds and poultry feeds show the largest num- 

 ber of deficiencies. The cottonseed meals were decidedly in- 

 ferior in quality, one-half of them being deficient in protein. 



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 nitro- 

 gen 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 certain other compounds 

 which contain nitrogen, for all practical purposes it is sufficiently 

 accurate. Protein, then, is made up of the compounds in the feed 

 which contain nitrogen. 



Fat is determined by extracting a dried sample of the feed- 

 ing-stuff with ether and weighing the residue after the ether is 

 driven oft". In main, it contains the vegetable fats of which olive 

 oil, linseed oil, and cottonseed oil are examples. It contains also 

 small amounts of chlorophyll, (the green coloring matter of the 

 leaves), waxes,' resins, etc.; but for practical purposes it is ac- 

 curate enough to deal with it as fat. 



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. 



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 percentages 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 per- 

 centage of crude fiber is called nitrogen free extract. 



