COMMERCIAL FEEDING-STUFFS 263 



that the old process meal responded to the swelling test, 

 but not the new process, a result due probably to the 

 steam cooking of the latter. This may serve as a means 

 of determining the method used in manufacturing a 

 given lot of meal, but probably has no special signifi- 

 cance as to feeding value, unless it indicates the new pro- 

 cess meal to be less useful in making a porridge for feed- 

 ing calves. 



CHEMICAL DISTINCTIONS IN CATTLE FOODS 



The classes of cattle foods as arranged in the previous 

 discussion have had reference to several factors, chiefly 

 those relating to origin and texture. Chemical facts have 

 not been considerd in these divisions. There are, how- 

 ever, certain chemical differences among the various 

 groups of feeding-stuffs, a knowledge of which is helpful 

 in selecting materials for compounding rations. 



356. Coarse foods vs. grains and grain products. In 

 comparing hays, straws, and other fodders with grains 

 and grain products there are points of chemical unlike- 

 ness which bear an important relation to problems of 

 nutrition. In the first place, the nitrogen compounds 

 differ. In the grains we find the nitrogen combined mostly 

 in the form of true proteins, while in the fodders and 

 roots a proportion of it, and sometimes quite a large 

 one, exists in amides. This is a point in favor of the 

 grains, for the nutritive function of amides is probably 

 more limited than that of the true proteins. Again, the 

 non-nitrogenous material of the grains is in general 

 superior to that of the herbaceous cattle foods. In the 

 former, especially in the cereal grains, there is but little 

 fiber and the nitrogen-free extract is made up largely of 



