6l2 NUTRITION OF FARM ANIMALS * 



of the different feeding stuffs in the rations, however, remained 

 the same, except in a very few cases. 



On the whole, and despite some irregularities in the results 

 on single ingredients, Grandeau and LeClerc's results agree 

 with Wolff's in showing that work even at a somewhat rapid 

 walk does not materially affect the digestibility of rations. On 

 the other hand, they show a distinct decrease of the percentage 

 digestibility in the periods in which the work was done at a 

 trot. It scarcely seems that this effect can be ascribed to the 

 work as such, since the measured amount was less than in Wolff's 

 experiments and was not greater at a trot than at a walk. More- 

 over, mere horizontal locomotion at a trot, in some instances at 

 least, seems to have produced the same effect, which apparently 

 is due to the difference in gait. It is true that the rations were 

 heavier in the work periods and that this (722) may possibly 

 have affected the digestibility, but no reason is apparent why 

 it should have produced a greater effect in the trotting periods 

 than in the walking periods. 



The influence of work has also been investigated in a different way 

 by Tangl 1 and by Scheunert. 2 A weighed amount of oats was fed 

 after 36 hours of fasting and the animal was killed from one to five 

 hours later and the contents of the stomach and small intestines 

 weighed and analyzed. On the assumption that none of the crude 

 fiber of the oats was digested in this portion of the alimentary tract, 

 the results show that work delays the passage of the feed from the 

 stomach to the intestines, especially during the first one or two hours. 

 As a consequence, the gastric juice penetrates the larger mass of the 

 feed more slowly and more of it is neutralized by the saliva, so that 

 the stage of starch digestion is prolonged and that of protein diges- 

 tion shortened, the result being that more carbohydrates and less pro- 

 tein are digested. In the later stages of digestion the differences tend 

 to equalize themselves, while the effect of work upon the intestinal 

 digestion was found to be small. Scheunert computes that the total 

 digestibility was considerably increased by the performance of work. 

 As noted, however, the results cover only the first five or six hours 

 of digestion. The method of comparison is confessedly an approxi- 

 mate one and the results show very considerable variations among 

 themselves. Only actual digestion experiments suffice to decide the 

 question of the total effect of work upon digestion. 



1 Arch. Physiol. (Pfliiger) ; 65 (1896), 545. 



2 Arch. Physiol. (Pfliiger) ; 109 (1905), 145 J Landw. Jahrb., 34 (1905), 805. 



