18 PRINCIPLES OF FEEDING FARM ANIMALS 



f. Nitrogen-free extract is obtained by subtracting the sum of the 

 percentages of the preceding components from 100. It includes chiefly 

 starch, sugar, pentosans, and organic acids (p. 13). The amounts of the 

 first three components are also sometimes determined separately by well- 

 known methods of analysis of interest mainly to chemists. 3 



The example given below will show the customary form of re- 

 porting analyses of feeding stuffs. 



Chemical Analysis of Timothy Hay 



Per cent 



Moisture 13.2 



Crude protein 5.9 



Fat 2.5 



Fiber 29.0 



Nitrogen-free extract 45.0 



Ash . 4.4 



100.0 

 QUESTIONS 



1. Name the elements essential to plant growth; also some others that 



are always present in plants. 



2. What are the groups of plant components determined in ordinary chemical 



analyses? 



3. Give the main characteristics of each one of these components. 



4. What is protein, nitrogen-free extract, carbohydrates? 



5. State the difference in the chemical composition of these substances. 



6. Give the ordinary form of reporting a chemical analysis of a feeding 



stuff. 



3 For complete directions for making chemical analyses of feeding 

 stuffs and other agricultural products, see Official and Provisional Methods 

 of Analysis, Association of Official Agricultural Chemists, Bureau of 

 Chemistry, U. S. Department of Agriculture, Bulletin 107 (Revised), 

 Washington, 1912. 



