14 PRINCIPLES OF FEEDING FARM ANIMALS 



All carbohydrates are composed of the three elements 

 carbon, hydrogen, and oxygen, the two latter generally 

 being in the proportion to form water {i.e. there are twice 

 as many atoms of hydrogen as of oxygen in the molecule), 

 from which the name, carbohydrate, is derived. Thus the 

 chemical formula of glucose is C6H12O6, of sucrose, C12H22O11, 

 and of starch, (C6Hio05)n. As indicated by these formulae, 

 some of the carbohydrates are comparatively simple com- 

 pounds, others are more complex, while still others are very 

 complex. Glucose or grape sugar and fructose or fruit 

 sugar are the simplest carbohydrates of importance. They 

 are represented by the chemical formula, C6H12O6. Sucrose 

 or cane sugar, lactose or milk sugar, and maltose or malt 

 sugar are more complex compounds as indicated by the 

 formula C12H22O11. The starches, celluloses, dextrins, etc., 

 are complex carbohydrates, having the formula (CeHioOs)^, 

 the n representing an unknown number. The pentosans 

 are complex carbohydrates having the formula (C5H804)„. 

 Under the proper conditions, the complex carbohydrates 

 can be changed to the simpler forms. Further reference 

 will be made to this fact under the discussion of the digestion 

 of the carbohydrates. 



On account of their difference in solubihty and nutritive 

 value, chemists usually divide the carbohydrates of feeding- 

 stuffs into two sub-classes, nitrogen-free extract and crude 

 fiber. 



Nitrogen-free Extract. — The nitrogen-free extract con- 

 sists largely of starches and sugars, ^vith small amounts of 

 less important carbohydrates, such as the pentosans. Starch 

 is the principal carbohydrate found in the nitrogen-free 

 extract of most feedingstuffs. It is found especially in the 



