THE DIGESTIBILITY OF FEEDINGSTUFFS 



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experiments. In a digestion experiment, the feedingstuff is 

 first analyzed to determine the percentage of each nutrient 

 present. The animal then is fed weighed quantities of the 

 feedingstuff under experimentation for a period of one or two 

 weeks, called the prehminary period, during which time the 

 residues of previous feeding are excreted from the body. 



Fig. 12. — Digestion harness on a pig. (Illinois Experiment Station.) 



The preliminary period is followed by a test period of one 

 to three weeks in length. During the test period, the ration 

 is weighed carefully, deducting the weight of any uneaten 

 residue. The feces of the animal are collected usually in a 

 rubber bag which fastens on to the hindquarters of the animal 

 by a light harness. Figure 12 shows a digestion harness on 

 a pig. Sometimes, especially in the cases of cattle and horses, 

 they are collected with a shovel by attendants who watch the 



