1912. 



PUBLIC DOCUMENT — No. 31. 



47 



DIGESTION EXPERIMENTS WITH CATTLE 



FEEDS. 



BY J. B. LINDSEY. 



The term " digestibility " refers to that portion of food that 

 an animal can actually make use of for nutritive purposes ; 

 the undigested portion is represented by the solid manure 

 (feces) which is excreted by the animal as so much worthless 

 material. 



The unit of measurement is termed " digestion coefficient." 

 Thus, experiments have shown that out of 100 pounds of bran 

 62 pounds, or 62 per cent., are digestible, and this figure is 

 termed the digestion coefficient for bran. Again, experiments 

 have shown that 77 per cent, of the protein and only 39 per 

 cent, of the fiber in bran are digestible, and these two figures 

 represent, respectively, the digestion coefficients for the protein 

 and fiber in bran. Coefficients are used in figuring out balanced 

 rations and in determining the relative nutritive values of 

 different feedstuffs. A single illustration as to the method em- 

 ployed in calculating the actual digestible material in a food- 

 stuff may suffice : — 



One Hundred Pounds Timothy Hay. 



Contains 

 (Per Cent.). 



Per Cent. Di- 

 gestible 

 (Coefficient). 



Pounds 

 Digestible. 



Water, 



Ash, 



Protein, . 



Fiber, 



Starchy matter. 



Fat, 



Total, 



15 00 

 4.30 

 6.30 

 28.40 

 43 60 

 2.40 



3 

 16.5 

 27 5 



1.5 



100 00 



48.5 



