74 EXPERIMENT STATION RECORD. 



It is plain that no storage in tbe body can take place except when 

 the food contains more nntritive material than is required for the mere 

 maintenance of the animal. The above table serves as a good illus- 

 tration of this fundamental principle, and shows also that the produc- 

 tion in the body, as far as the fat is concerned, within certain limits is 

 proportional to the amount of nutrients in the food in excess of that 

 required for maintenance. 



An exact, constant relation between the excess of nutrients and the 

 storage of fat can not be expected on account of the difference in the 

 individuality of the animals. However, the above results show that, 

 on an average, an excess of 1 kg. of digestible organic matter resulted 

 in the formation of 0.24 kg. of fat. Since, according to tliis, the pro- 

 duction of 0.446 kg. represents approximately 1.8 kg. of nutrients, 

 it is calculated that with no increase of fat the requirement would be 

 7.3 kg. of digestible organic matter, which agrees with tlie maintenance 

 ration mentioned above (0.7 kg. of digestible protein and (5.6 kg. of 

 digestible nitrogen-free extract). 



Considering the cases in which starch meal was added to bring the 

 ration up to a produ(;tive ration, it is calculated that on an average the 

 addition of 21.06 kg. of starch meal to the mainteimnce ration was fol- 

 lowed by the production of 4,295 kg. of fat. In other Avords, 1 kg. of 

 starch meal resnlted, on an average, in the production of 0.2 kg. of fat. 

 How much of this fat was formed directly from the starch and how 

 much was a result of the conserving action of the starch can not be 

 stated. It is oidy certain that under the above mentioned conditions, 

 on an average, an amount of fat was ])roduced in the body representing 

 34 per cent of the carbon contained in the excess of carbohydrates in 

 the ration. 



It is believed that the question as to whether carbohydrates (starch 

 meal) can be changed to fat in the nutrition of cattle is answered in the 

 affirmative by the results of the first 3 series of experiments. 



Assuming on the one hand that the total amount of carbon in the 

 protein was used in the formation of fat, and on the other hand that 

 the digestible ether extract of the food was stored as fat in the body 

 without loss, there still remains an amount of fat in the body unac- 

 counted for, and for the production of which there is no other visible 

 source than the carbohydrates of the food. Even if it is assnmed that 

 a portion of the carbon served for the production of glycogen, the con- 

 clusion as to the formation of fat from carbohydrates remai ns un changed . 



With respect to the second point, i. e., the excretion of hydrocarbons 

 by cattle, organic carbon compounds were invariably found in the 

 gaseous excretion of all the animals, and these bore a certain relation 

 to the total amount of carbon excreted in the gaseous products, but did 

 not bear the regular proportion to the digestion of crude fiber that has 

 been indicated by the experiments of Tappeiner. It is not improbable, 

 the authors think, that the different groups of nutrients bear an unequal 



