Thus, then, alike for maintenance, for increase, and for the exercise of force, the exigencies of the system are characterized more by the demand for the digestible nonnitrogenous or more specially respiratory and fat-forming constituents than by that for the nitrogenous or more specially flesh-forming ones.
Concentrated and digestible foods give best results, a pig has a small stomach.
In the feeding experiments which have been carried on at Rothamsted it has been shown that the amount consumed both for a given live weight of animal within a given time, and for the production of a given amount of increase, is, as current food-stuffs go, measurable more by the amounts they contain of digestible and available non-nitrogenous constituents than by the amounts of the digestible and available nitrogenous constituents they supply.
The quantity of digestible nutritive matter in 1000 lb of ordinary feeding-stuffs when supplied to sheep or oxen is shown in Table XIX.
Hence it is that the amount of food consumed to produce a given amount of increase in live weight, as well as that required for the sustentation of a given live weight for a given time, should - provided the food be not abnormally deficient in nitrogenous substance - be characteristically dependent on its supplies of digestible and available non-nitrogenous constituents.
Warington states that the proportion of nitrogenous to non-nitrogenous matter in the digestible part of potatoes is as i to io 6.
Hence, as current fattening food-stuffs go - assuming, of course, that they are not abnormally low in the nitrogenous constituents - they are, as foods, more valuable in proportion to their richness in digestible and available nonnitrogenous than to that of their nitrogenous constituents.