VALUATION OF FOODS 123 



When the market price is in excess of the estimated 

 value the food is generally dear, when below, it is 

 cheap, provided the condition is good and it is suitably 

 blended. It will be noticed that this system does not 

 take any notice of the palatability of a food, and only 

 indirectly the digestibility, but includes manurial value. 



(b) Manurial Residue. The undigested part of the 

 food, known as the solid excrement, is fairly rich in 

 nitrogen, phosphates, and potash, consequently it 

 has considerable value as a manure for farm crops. 

 Further, the digested part is only partially retained 

 by the animal body, which makes the liquid excrement 

 rich in nitrogen and potash. 



These residues have been valued by Hall and 

 Voelcker in the following table (see pp. 124-26). In 

 practice the full theoretical manurial value of the residue 

 is not realised, on acount of leakage, which is, even with 

 the greatest care, considerable, and in other cases 

 enormous. An allowance has been made in the last 

 column of the table for leakage of manurial constituents, 

 but it is necessary that precautions should be taken to 

 have an impervious floor, to prevent washing by rain as 

 well as heating of the manure, if these manurial values 

 are to be realised. 



The net cost of the food for feeding purposes is 

 therefore the total cost per ton, less the value of the 

 residue actually retained in the manure. 



XIX. PREPARING POODS FOR STOCK. 



Several devices have to be adopted by the feeder 

 of stock to overcome difficulties which arise in his 

 efforts to supply the stock with a wholesome, palatable, 

 and at the same time economical ration. Some of 

 these are as follows : 



