6i6 



NUTRITION OF FARM ANIMALS 



One would naturally be inclined to ascribe the lower diges- 

 tibility of heavier rations to their greater bulk and relatively 

 more rapid passage through the digestive tract, and in part to 

 the consequent lessened extent of the bacterial fermenta- 

 tions. It would seem that on liberal rations material poten- 

 tially digestible and resorbable may thus escape digestion and 

 appear in the feces. Some of the reasons for this have al- 

 ready been indicated in discussing the feces as a feed residue 

 (155). The presence of considerable amounts of undigested 

 grains or fragments of grain in the feces of heavily fed animals 

 is readily demonstrated by washing out the finer portions, but 

 actual digestion experiments to determine the extent of this 

 loss have not yet been reported. 



723. Excess of carbohydrates. It has been established by 

 numerous experiments that an undue proportion of carbohy- 

 drates in a ration tends to reduce its digestibility, especially by 

 ruminants. The effect is most distinct when pure digestible car- 

 bohydrates are added to a ration, but is manifest also when large 

 amounts of feeding stuffs rich in carbohydrates are introduced. 



An example of the former is afforded by an experiment by 

 G. Kiihn 1 on two oxen. It was divided into three periods, in 

 the first of which the animals received a daily ration of 9 kgs. 

 of hay to which, in the second and third periods, 2 kgs. and 3. 5 

 kgs. of starch, respectively, were added. Assuming the starch 

 to have been completely digested 2 the following amounts of 

 the several ingredients were computed to have been digested 

 from the hay by Ox V. 



TABLE 178. NUTRIENTS DIGESTED FROM HAY, WITH AND WITHOUT 



STARCH 



1 Landw. Vers. Stat., 44 (1894), 470-472. 



2 No starch could be detected microscopically in the feces. 



