362 MA.NUAL OF OATTLE-FEEDIlira-. 



therefore, of the nitrogen-free extract of roots may be as- 

 sumed to be similar to tliat of starch. 



Variations in Composition. — It is observed in all roots 

 that, other things being equal, the water content increases 

 with the size of the root, and consecpently the quantity of 

 dry matter decreases. 



The richer the soil and the more heavily it has been 

 manxn'-ed, OKspecially with yard manure, the greater is usu- 

 ally the percentage of protein in the dry matter of the 

 roots. The different kinds of roots, however, show differ- 

 ences in this respect. Sugar beets are the poorest in pro- 

 tein and contain the most dry matter, at least when tliey 

 develop according to the wish of the sugar manufacturer. 

 Large sugar beets, weighing two pounds and over, such as 

 are produced by heavy green manuring and too wide set- 

 ing, have a composition more resembling that of ordinary 

 mangolds. 



Feeding" Value. — The foregoing consideration of the 

 chemical composition of tubers and roots points out un- 

 mistakably their true value as fodder. Aside from their 

 succulence and paktability, and any specific dietetic action 

 which they may exert, their value lies in their non-nirro- 

 genous ingredients. They contain but little nitrogenous 

 matter and only a portion of this is true protein, so that 

 unless very large amounts of them are fed these constitu- 

 ents are of little account- The carbhydrates and pectin 

 substances which they contain, on the other hand, are pres- 

 ent in large quantities, are easily digestible, and furnish a 

 ready source of non-nitrogenous nutrients. 



These feeding-stuffs are generally assumed to be wholly 

 digestible. It is not likely that this is strictly true, but 

 their digestibility is so great that no serious practical error 

 is involved in the assumption of complete digestibility. 



