io Wyoming Experiment Station. 



animal. The rest passes on and out as the undigested portion. 

 The excretions from the lungs, skin, and kidneys are disre- 

 garded, as these are the waste products of the animal met- 

 abolism which have served their purpose in nourishing the 

 animal. 



DIGESTION COEFFICIENTS HOW OBTAINED. 



If, then, we determine the weights of the different con- 

 stituents of a food eaten in a given time and determine the 

 weights of the different constituents of the feces, the dif- 

 ference will represent the weights of the constituents "of the 

 food which have been digested, absorbed, and have become 

 available for nourishing the animal. These results are gen- 

 erally given in percentages of the constituents of the food 

 eaten and are known as digestion coefficients. 



ERRORS WHICH CANNOT BE AVOIDED. 



As the digestive fluids which are secreted upon the food 

 are not completely absorbed again, and as the waste from the 

 interior of the alimentary canal is constantly being cast with 

 the feces, there is always a small error entering into the re- 

 sults which cannot be avoided, but this is assumed to be small 

 and is neglected. The real digestion coefficients of some of 

 the constituents of the food, then, are a little higher than those 

 determined by experiment, but the error is too small to ma- 

 terially affect results. 



DEFINITIONS OF TERMS. 



As the terms used in this bulletin may not be well under- 

 stood by many who will read it, it may be well to give ex- 

 planations and values of each. 



WATER. Although a feed may seem perfectly dry to the 

 touch and even powder easily, some water is always found. 

 In growing fodders, water is by far the greatest constituent 

 by weight. In dry feed it varies, depending upon the manner 

 of curing, the amount of water vapor in the atmosphere, etc. 



