208 THE CHEMISTRY OF CATTLE FEEDING 



cases under consideration, but it does not hold good in all. 

 Pigs might be fattened more or less rapidly. They might 

 even be kept strictly in store condition throughout the whole 

 period of growth. In any case, there will be no true fattening 

 until the requirements for growth have been satisfied. 



Judging from the data given above, and others of a similar 

 kind, it appears that the maximum increase due to growth in 

 very young pigs is about 2 per cent, of the live weight per 

 day. But the rate of increase due to growth gradually 

 diminishes as the animals grow bigger, and when they are 

 full grown it is zero. Upon further consideration of the 

 data it appears that the actual increase due to growth 

 in any given case may be found, approximately, by the 

 formula 



2(M'-M) 

 3 M' 



M is the actual live weight of the animal, and M' the maximum 

 live weight in the store condition. 

 Since F = I G 



therefore 



2 (Mi M) 

 F = I -- * L 



If the value of G, according to the formula, be determined 

 for each case given in the tables and added to F reckoned as 

 o'4 per cent, of the live weight, it will be found that the sum 

 of the two numbers corresponds very closely, in most cases, 

 with the total increase actually observed. For these calcula- 

 tions, the live weight of the full-grown animals in the store 

 condition (M') was taken as 400 Ibs. ; but in some it must 

 have been larger, and, possibly, in others it was less. For 

 reasons given above, however, the value of F must, in general, 

 be taken as the difference between the total increase and that 

 diie to growth. 



When the amount and composition of both parts of the 

 increase are known, the amounts of nutrients required to 

 produce them may be estimated by the methods previously 



