316 FEEDING WITH SUGAR BEETS, SUGAR, ETC. 



1st. 2d. 3d. 4th. 5th. 



Artificial digestion ... 20.57 %. 14.41 %. 13.22 %. 10.83 %. 10.69 %. 

 Natural digestion .... 21.46 %. 15.4 %. 13.65 #. 11.32%. 9.93$. 



The proportions would be much higher if no allowance were made for the 

 nitrogen furnished by the body during assimilation. Kellner's experiments 

 show that for every 100 parts of dry digested substances, there is at least 2 

 part of nitrogen furnished by the body, etc. As the number of comparative 

 experiments between natural and artificial digestion is very limited, it would 

 be a mistake to attacli too much importance to any of them or to abandon exist- 

 ing coefficients of digestibility to adopt those based upon artificial digestion. 



A fact to be borne constantly in mind is that the digestibility of protein 

 is the most important question relating to cattle feeding ; on it success de- 

 pends. However, even when these nitrogenous substances are not digested, 

 they are not entirely lost, as they are subsequently used upon the soil as fer- 

 tilizers. The plant laboratory does slowly what might have been accomplished 

 rapidly in the stomach. A complete assimilation is doubly advantageous to 

 the farmer, as more meat is produced on the one hand, and on the other the 

 nitric elements in the fertilizers are nearly the same as they would have been 

 had they contained protein in excess. In the latter case it is taken up 

 slowly by the plant in growing, while when in a more soluble form, such as 

 urea, the absorption is almost immediate. Numerous investigators, Henne- 

 berg, Kuhn, Schultze, etc., have demonstrated that when the digestive ratio 

 diminishes, the coefficient of digestibility of protein decreases. The use of 

 so-called nutritive equivalents based upon their percentage of nitrogen is not 

 accepted by all authorities. Stohmann's experiments point to the fact that it 

 is possible to admit a formula having a variable factor so as to make allow- 

 ances for each special case, the value of which should be based upon practical 

 experiments. 



The Stohrnann formula now generally accepted was not the first; and many 

 more recent ones are very satisfactory and give results that are sufficiently 

 correct for most practical purposes. 



~ ~ . ,. ,. ., ... ,, Fats + Nitrogen free extract 



Coefficient of digestibility of protein = 



.Protein -f- Carbohydrates. 



Digestibility of carbohydrates. As previously mentioned, carbohydrates have 

 a decided influence on the digestibility of feeds, upon protein and crude fibre 

 substances especially. In the experiments of Stutzer and Isbert to determine 

 the artificial digestion of carbohydrates without fat, it is shown that they may 

 be dissociated by the action of ferments into two parts, one of which is digestible 

 and the other indigestible. Here again the results in artificial digestion must 

 not be confounded with those of digestion under normal conditions; in the latter 

 there is a series of micro-organisms which have an important influence and may 

 in a measure dissolve the carbohydrates to a greater extent than would have been 

 possible by the action of ferments considered alone. Attention is called to the 

 importance of undertaking some new experiments in this direction, to deter- 



