Combination of Nutrients 135 



or warm. Such variations may influence digestibility, 

 though no actual demonstration of this fact appears to 

 be on record. The question is often asked whether the 

 storage of hay for a long period affects its nutritive 

 value. The data from four series of experiments 

 touching on this point indicate that there is a per- 

 ceptible, though not marked, decrease in digestibility of 

 hay during long -continued storage. 



INFLUENCE OF THE COMBINATION OF FOOD NUTRIENTS 



Among the apparently important and freely ex- 

 ploited conclusions drawn from investigations in ani- 

 mal nutrition is the statement that the -digestibility of 

 food is influenced to a marked degree by the relative 

 proportions of the several classes of nutrients. It is 

 taught that if more than a certain percentage of starch 

 and sugar, or of feeding stuffs rich in carbohydrates, 

 like potatoes or roots, is added to a basal ration, the 

 digestibility of the latter is decreased, the protein and 

 fiber being especially affected. The conclusions, as 

 stated by Dietrich and Konig, on the basis of a criti- 

 cal study of the data involved are that if pure carbo- 

 hydrates are used to the extent of more than 10 per 

 cent of the dry substance of a basal ration, or if pota- 

 toes and roots are fed equivalent in dry matter to 

 more than 15 per cent, a depression of digestibility 

 occurs, which increases with the amount of carbo- 

 hydrate material added. A modifying conclusion is, 

 that if the addition of the carbohydrate material is 

 accompanied by correspondingly more protein, the de- 



