180 THE CHEMISTRY OF THE FARM 



for practical use, a margin admitting of a small pro- 

 duction must be allowed in order to provide for the 

 growth of hair, hoofs, &c., if the animal is to continue 

 permanently in health. Lean oxen of 1,370 lbs. 

 weight, fed on hay, will require in practice a daily 

 ration of 10 lbs. digestible organic matter, or 7*3 Ibs.^ 

 per 1,000 lbs. live weight. Of this 7*3 lbs. of digestible 

 matter, 0*7 lb. will be nitrogenous substance, including 

 (if ordinary hay was used) 0*54 lb. albuminoids. The 

 ratio of nitrogenous to non-nitrogenous substance is 

 here 1 : 9"4, and the true albuminoid ratio 1 : 12 '4. 



A fat ox requires more food to maintain an 

 unchanged condition than a lean ox of the same 

 size. Kellner experimented with fat oxen up to 

 1,888 lbs. live weight. An ox of 800 kilos. (1,760 lbs.) 

 required a daily ration supplying 19,920 Calories, or 

 one-quarter more food than a lean ox of the same 

 weight. A fat ox also requires a rather larger propor- 

 tion of albuminoids in its diet. 



It is essential that a maintenance ration should 

 supply enough albuminoids to replace the daily waste 

 of the nitrogenous tissues. While the albuminoids of 

 the maintenance ration serve this special purpose, they 

 at the same time form an effective part of the heat- 

 producing food, as they take the place of matter that 

 is being burnt in the body. An animal is receiving 

 the minimum amount of albuminoids required for its 

 sustenance when any diminution in the daily supply 

 occasions a larger amount of nitrogen to leave the 



1 If the digestible matter of the hay is to be valued at 3*5 Caloriea 

 per gram, and starch at 3*7 Calories, as before, then the 10 lbs. and 

 7*3 lbs. of digestible organic matter will be equal to 9*46 lbs., and 

 6*9 lbs. of starch. 



