2io THE CHEMISTRY OF CATTLE FEEDING 



the fattening portion of the ration except what was spent 

 in the work of digestion, and this has been allowed for 

 in the calculation must have been stored up as fattening 

 increase. 



In the Rothamsted experiments the pigs were allowed an 

 unlimited amount of food, consis\ing chiefly of barley meal, 

 and they fattened more rapidly than those in the experiments 

 described above. The amounts of food required, calculated 

 on the same basis as the latter, were much less than was 

 actually consumed. It is evident, therefore, that in the 

 Rothamsted experiments the whole of the digestible nutrients 

 was not stored up. Apparently only about 60 per cent., 

 i.e. about the same as in oxen, was stored up as fattening 

 increase. 



If both sets of experiments are to be relied upon, it seems 

 clear that the percentage of the digestible nutrients that pigs 

 can store up as body fat depends to some extent upon the 

 amount of food consumed in proportion to the live weight of 

 the animal. 



An important question of pecuniary economy arises in 

 this connection. If the animals store up a larger proportion 

 of the nutrients when the quantity of the food is duly limited 

 than when it is not, it might appear at first sight that the 

 former is the more economical method of feeding. It must 

 be remembered, however, that when the food is limited, the 

 rate of increase is slower, and the portion of the food which is 

 dissipated in simple maintenance is consumed daily. The 

 data at hand are not sufficient for the solution of this problem 

 on a chemical basis. 



The difficulties revealed above may possibly suggest that 

 it is the method of investigation that is at fault, and that, in 

 this case, at least, it would be better to adhere to the older 

 method of feeding standards. That recommended by Kellner 

 for full-grown pigs gives about 3 Ibs. of digestible protein 

 and 28 Ibs. of total digestible non-nitrogenous nutrients 

 reckoned as starch, per 1000 Ibs. live weight, corresponding 

 to the following quantities per head (calculated by rule of 

 three). 



