RELATIVE VALUES OF FEEDING STUFFS 



6I 7 



' Expressed in another way, the feces in Periods II and III 

 contained the following amounts of hay ingredients which, ac- 

 cording to the results of Period I, must be regarded as digestible, 

 but which under the influence of the addition of starch escaped 

 digestion. 



TABLE 179. DIGESTIBLE NUTRIENTS OF HAY ESCAPING IN FECES 



The foregoing is a typical example of the results of numerous 

 similar experiments on ruminants in which starch, sugar, pectin 

 substances and even cellulose have been added to hay and to 

 mixed rations. Other things being equal, the magnitude of the 

 effect has usually increased, as in this instance, with the quan- 

 tity of carbohydrates added. Its total amount has varied con- 

 siderably in different experiments, but qualitatively the result 

 has been uniformly the same. This constitutes the so-called 

 " depression of digestibility," since, of course, the digestion 

 coefficients are lowered by the escape of potentially digestible 

 matter in the feces. It should be noted, however, that in some 

 of these instances more or less of the added carbohydrate (starch) 

 has itself escaped digestion. According to experiments by 

 Wolff, 1 swine appear to be much less sensitive to this influence 

 of carbohydrates than are ruminants and a few observations 

 by Grandeau and Alekan 2 seem to indicate that the same 

 may be true of the horse. 



724. Feeding stuffs rich in carbohydrates, as well as such ma- 

 terials as starch or sugar, may apparently likewise cause a de- 

 crease of digestibility, although the quantitative relations can- 

 not always be so clearly followed as in experiments with pure 

 carbohydrates. Thus six experiments with beet molasses by 



1 Landw. Vers. Stat., 19 (1876), 273. 



2 Jahresber. Agr. Chem., 49 (1906), 350; Ann. Sci. Agron., 1904, I, 30, 330. 



