CHAPTER III. 



DIGESTIBILITY RESPIRATION CALORIMETRY ENERGY. 



I. DIGESTIBILITY. 



The method of determining the digestibility of feeding stuffs is 

 based on the fact that the undigested portion of food passes from 

 the body in the so-called solid excrement. In studying the diges- 

 tibility of a given feed the chemist first determines by analysis the 

 percentage of each nutrient it contains. Weighed quantities of the 

 feed are then given to the animal, and the solid excrement voided 

 during a stated period is saved, weighed, and samples analyzed. 

 The difference between the amount of each nutrient fed and that 

 found in the solid excrement resulting therefrom represents the 

 digested portion. 



58. A digestion trial with sheep. The following description 

 covers an actual digestion trial conducted by Armsby at the Wis- 

 consin Station. 1 Desiring to ascertain the digestibility of clover 

 hay and malt sprouts, 2 wethers weighing 87 Ibs. each were confined 

 in specially constructed apartments and fed from zinc-lined boxes 

 to prevent waste. Each day's allowance was weighed and samples 

 analyzed. The solid excrement passed by the wethers was col- 

 lected in rubber-lined bags attached to their hind quarters by a 

 light harness. These bags were emptied each 24 hours, and the 

 contents weighed and analyzed. Feeding progressed 6 days before 

 the trial proper began, in order that all residues of previous feed 

 might have passed from the alimentary tract. During the first 

 period each sheep, as shown in the table, was fed 700 grams (about 

 1.5 Ibs.) of clover hay daily, which was consumed without waste. 



Digestion trial with sheep fed clover hay; .average for 1 day. 



'Kept. 1884. 



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