248 EXPERIMENT STATION. [Jan. 



" vegetable meat." It serves as the exclusive source of flesh, as well 

 as a source of heat or energy, and fat. 



Fiber is the coarse or Avoody part of the plant. It may be called 

 the plant's framework. It is a source of heat or energy and fat. 



Nitrogen-free extract represents the sugars, starches and gums. It 

 is the principal source of heat or energy and fat. 



Fat includes not only the various oils and fats in all grains and 

 coarse fodders, but also waxes, resins and coloring matters. It is 

 also termed ether extract because it is that portion of the plant soluble 

 in ether. It serves as a source of heat or energy and body fat. 



Under digestibility the figures mean that so many pounds of protein, 

 fiber, nitrogen-free extract and fat in 100 pounds of the fodder are 

 actually digested and made use of by the animal. No feed is entirely 

 digestible; concentrates are more digestible than coarse fodders. The 

 data inider digestibility have been worked out by actual experiment. 

 In cases where no figures appear, data as a result of experiments are 

 lacking. 



Net Energy Value. — The entire amount of heat or energy contained 

 in a feeding stuff is termed its total heat or energy value. All of 

 this heat or energy cannot be utilized by the animal for the purposes 

 of maintaining its body in a state of equilibrium, or for aiding in the 

 production of growth and milk. The several losses may be enumerated 

 as follows: (a) the undigested material, i.e., the faeces; (b) the incom- 

 pletely used material of the urine; (c) the work required in the proc- 

 esses of digestion and assimilation in preparing the nutrients so that 

 they can be used for maintenance and for the production of growth 

 and milk. These several sources of loss expressed as energy, deducted 

 from the total energy, leaves the real or net energy value. 



The calorie is the unit of energy measurement. 



The small calorie represents the amount of heat required to raise 

 1 gram of water 1° C. 



The large calorie represents the amount of heat necessary to raise 

 1 kilogram (1,000 grams) of water 1° C. 



The therm, a name proposed by Armsby, represents the amount of 

 heat required to raise 1,000 kilograms of water 1° C. It is to be pre- 

 ferred to the small or large calorie as a unit of measurement be- 

 cause it can be expressed in fewer figures. 



In the last column of the following table, headed net energy value, is 

 given the number of therms contained in 100 pounds of tlie different 

 feeding stuffs, based on the results of very carefully conducted experi- 

 ments by Kellner, a German investigator.^ 



> For a fviU explanation of the components of the animal body, the composition of feeds, the 

 different ways in which the food is ixsed in the animal body and the explanation for using the 

 therm in the calculation of rations for farm animals, see Farmers' Bulletin 346, United States 

 Department of Agriculture, prepared by H. P. Armsby. 



