THE FATTENING ANIMAL 191 



»- 



used to the best advantage. This does not, of course, 

 mean that if a fattening ox is fed on hay and mangels 

 it will gain 1 lb. in weight for each 9 lbs. of hay, or 

 30 lbs. of mangel consumed ; the amount of food 

 required for the animal's maintenance must be de- 

 ducted from the total food supplied, and the excess 

 of food alone must be credited to increase. Nor must 

 it be forgotten that the maintenance food of an 

 animal in a fattening condition is considerably greater 

 in quantity than that required by a lean animal of 

 the same weight (p. 180), and that the demand for 

 maintenance increases as the process of fattening 

 advances. 



In the examples we now proceed to give of the 

 results obtained when fattening oxen, sheep and 

 pigs, the quantities of food mentioned are the total 

 amounts consumed by the animal, no distinction being 

 attempted between the maintaining and the producing 

 portions of the ration ; this is inevitable in the case 

 of the sheep and pig, as the requirements of these 

 animals for maintenance are not as yet accurately 

 known. In the case of the ox, the amount of food 

 required for maintenance has been most carefully 

 determined ; but even in this case we do not 

 exactly know what portion of the maintenance 

 ration must in any given case be deducted from a 

 liberal diet to obtain the amount available for pro- 

 duction.^ Kellner's production values of food were, 



' We have already seen that the fibre in the food of an ox only pro- 

 vides the animal with sufficient energy for its own mastication and 

 digestion ; the digested fibre thus contributes to the heat of the 

 animal, but takes no share in the production of increase. A part of 

 the maintenance ration must not consist of fibre, as internal work 



