RESPIRATION AND EXCRETION 43 



the form of solid excrement. Seeing that the food 

 canal of ruminants is from twenty to thirty times the 

 length of the body, while in horses and pigs it is from 

 ten to fifteen times, the food naturally remains in the 

 alimentary canal some time before the undigested part 

 is finally expelled. With pigs and horses this period 

 may be about two days, while with ruminants four to 

 six days may be required. 



XII. POODS AND FEEDING STUFFS. 



Feeding stuffs may be divided into those which are 

 comparatively rich in one or more of the three most 

 valued nutrients viz., albuminoids, 1 fats, and carbo- 

 hydrates (concentrates), and those feeding stuffs which 

 are comparatively poor in the above - mentioned 

 nutrients (bulky foods). 



The former are represented by the various oil- 

 cakes, pulse grains (peas and beans), cereal grains 

 (wheat, rye, barley, oats, maize, and rice), including 

 by-products from flour mills, breweries, distilleries, 

 etc. ; while the latter includes grass, clover hay, seeds 

 and meadow hay, straw from cereals, roots, etc. Bulky 

 fodders (hay and straw) are very rich in fibre, while 

 root crops are generally low in this constituent. 



The concentrates may be subdivided into groups 

 according to their richness in one or more of the three 

 most valued nutrients : e.g., oil-cakes, peas, beans, soya 

 beans, etc., are all rich in albuminoids ; flax seed, 

 cotton seed, soya beans, and rape seed are rich in oil ; 

 while wheat, barley, oats, maize, and rice are exceed- 



1 As the protein in concentrates consists largely of albu- 

 minoids, the common term "albuminoids" will be employed in 

 dealing with concentrates. 



