310 THE FEEDING OF ANIMALS 



This standard has been revised. The earlier experi- 

 ments on which it was based furnished data insufficient 

 for accurate conclusions, for the only means of judging 

 whether the animals were gaining or losing body sub- 

 stance were the changes in live weight, which cannot be 

 regarded as conclusive evidence. Some of the earlier 

 feeding experiments conducted in the United States, 

 especially those of Sanborn and Caldwell, indicated that a 

 ration based on Wolff's standard was capable of causing a 

 material growth of steers, and the accuracy of Wolff's 

 figures was called into question. Later observations of a 

 more exact character have shown quite conclusively that 

 a 1,000-pound steer may be maintained without loss of 

 body substances on considerably less than 8.9 pounds, or 

 even 8 pounds, of digestible nutrients a day. 



Elaborate experiments by Kuhn from the years 1882 

 to 1890, afterwards discussed by Kellner, were regarded 

 by the latter as justifying the conclusion that the mini- 

 mum quantity of digestible organic matter which will 

 maintain a 1, 000-pound mature ox at rest is 7.3 pounds, 

 .7 of a pound of which should be protein. Later Armsby, 

 in presenting the results of experiments of his own in 

 connection with a critical review of Kiihn's work, con- 

 cludes that "we may place the average maintenance of a 

 steer weighing 500 kgs. (1,100 pounds) and receiving 

 only a mainly coarse fodder at 13,000 calories of availa- 

 ble energy." As Armsby has found one gram of digesti- 

 ble matter from roughage to be equal to 3.5 calories of 

 available energy, 13,000 calories would equal 7 pounds 

 of digestible matter from this source. This would be 

 the same as 6.54 pounds for a 1,000-pound animal. 



Still later, Kellner, basing his figures upon extensive 

 researches by himself and associates, which were the 



