6i8 



NUTRITION OF FARM ANIMALS 



Lehmann 1 and one by Kellner 2 showed that this substance, 

 like the pure carbohydrates, caused a depression in the di- 

 gestibility of all the ingredients of a basal ration, but in two 

 later trials by Kellner 3 the only effect was on the digestibility 

 of the crude fiber. 



The question has been especially investigated, however, by 

 Wolff in regard to the feeding of tubers and roots. Heavy feed- 

 ing of these materials is generally stated, on the strength of his 

 experiments, to result in a pronounced decrease in the diges- 

 tibility of the remainder of the ration, although, as Wolff him- 

 self points out, the evidence is by no means conclusive. 



In Wolff's extensive series of experiments on sheep 4 increasing 

 quantities of roots or potatoes were fed along with hay whose diges- 

 tibility had been previously determined, and it was found that as the 

 amount of roots added to the ration was increased, the feces contained 

 increasing amounts of undigested nutrients. For example, in one 

 experiment with meadow hay and sugar beets, the percentage digesti- 

 bility of the hay, computed on the assumption that the sugar beets 

 were completely digestible, was as follows : 



TABLE 180. COMPUTED PERCENTAGE DIGESTIBILITY OF HAY WITH AND 

 WITHOUT SUGAR BEETS 



What seems a more reasonable method of comparison, however, 

 is to compute the digestibility of the roots in the first instance on 

 the assumption of unaltered digestibility of the hay, just as in the 

 case of concentrates (161) and to see whether the coefficients thus ob- 

 tained show any decrease as the proportion of roots fed is increased. 

 Wolff has carried out the computation in this manner for his entire 

 series of experiments, numbering in all no single trials. The aver- 



1 Landw. Jahrb., 25 Erzgbd. II (1896), 117. 



2 Landw. Vers. Stat., 53 (1900), 199. 

 3 Ernahrung landw. Nutztiere, 5th Ed., pp. 158-175. 

 4 Landw. Jahrb., 8 Ergzbd. I (1879), 123. 



