192 THE CHEMISTRY OF THE FARM ^ 



however, obtained by giving a known quantity of 

 food to an ox which was already receiving somewhat 

 more than a maintenance ration ; we are therefore 

 apparently justified in deducting the whole, or nearly 

 the whole, of the maintenance ration from the diet 

 of a fattening ox, if we wish to ascertain the quantity 

 of food available for increase in the sense understood 

 by Kellner. Taking, as an example, the Eothamsted 

 statistics for fattening oxen (p. 193), we see that an 

 ox of 1,200 lbs. live weight received 106 lbs. of 

 digested organic matter (including fibre) per week, 

 and produced 13"6 lbs. of increase. Such an ox, in 

 a fattening condition, would require, according to 

 Kellner, about 9 '63 lbs. per day of digested organic 

 matter for maintenance only, or 67*4 lbs. per week, 

 thus leaving 38*6 lbs. of digested food, reckoned as 

 starch, for production! Now as 3 lbs. of starch can 

 yield 1 lb. of increase, the 38'6 lbs. might yield 12 9 

 lbs. ; the actually observed increase being 13*6 lbs. 

 Calculating backwards, the 13*6 lbs. of increase 

 would require 40"8 lbs. of productive food, leaving for 



besides that of digestion has to be provided for. What fraction of the 

 maintenance ration must be non-fibrous is, in the case of the ox, 

 unknown ; in the case of the horse it must not fall below one-third of 

 the digested matter. If we suppose an ox to receive a maximum 

 amount of fibre in its maintenance ration, the amount of increase 

 produced by the addition of any food will be strictly limited by the 

 producing value of the food added. If, on the other baud, an ox is 

 maintained on food poor in fibre, and additional food is then added 

 for fattening, the waste heat produced during the deposition of 

 increase may enable a part of the maintenance food, previously 

 utilised for heat, to become productive, and the weight of increase 

 obtained will then exceed that proper to the food added. The return 

 from the additional fattening food thus depends, partly, on the 

 character of the rest of the diet. 



