CONDITIONS GOVERNING DIGESTIBILITY 55 



Work according to Wolff has no influence in causing a larger 

 proportion of food substances to be digested. Excessive work 

 perhaps causes a slight decrease in the amount digested. 



Combinations. Investigations show that the combination of 

 the nutrients of a food exerts an influence on its digestibility. 

 Corn added to hay produces no effect on the digestion of hay 

 unless it is added in large amounts when it decreases the di- 

 gestibility. Large amounts of carbohydrates tend to reduce the 

 digestibility of the protein and crude fiber in hay. This de- 

 crease is not great until the carbohydrates amount to 25 to 30 

 per cent, of the total dry matter in the hay, although it is much 

 larger if straw is included in the diet. This depression of di- 

 gestibility can be removed by adding more protein. It is be- 

 lieved that if carbohydrates form 10 per cent, of the dry matter 

 of a ration, or when roots or potatoes constitute more than 15 

 per cent, of the dry matter, the amount of digested substance 

 decreases and becomes greater as the carbohydrates are in- 

 creased. From these observations it is apparent that the ex- 

 cessive use of roots or tubers with hay or fodder, will de- 

 crease the digestibility of the ration unless the protein is in- 

 creased. Experiments indicate that albuminoids and oil added 

 to a ration do not increase the amount digested or do not alter 

 the digestibility. 



An Addition of Salt may improve the flavor of a food and thus 

 cause an increase in the amount of food eaten, but it does not 

 seem to be effectual in causing a larger per cent, of digestibility. 



Time of Watering and Frequency of Feeding. Experiments 

 have been run to ascertain the effect of the time of watering, 

 amount of water and frequency O'f feeding with the results that 

 no alteration in digestion took place. It should be understood 

 however that the ruminants should be fed and watered at least 

 twice a day and horses and mules three times a day for the best 

 results. 



