298 The Feeding of Animals 



animals were gaining or losing bodj' substance 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 ra- 

 tion based on Wolff's standard was capable of caus- 

 ing a material growth of steers, and the accuracy of 

 Wolff's figures was called into question. Later obser- 

 vations of a more exact character have shown quite 

 conclusively that a 1,000-pound steer may be main- 

 tained without loss of body substances on considerably 

 less than 8.9 pounds, or even 8 pounds, of digestible 

 nutrients per day. 



Elaborate experiments by Kiihn from the j^ears 

 1882 to 1890, afterwards discussed by Kellner, were 

 regarded by the latter as justifying the conclusion 

 that the minimum quantity of digestible organic mat- 

 ter 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, concludes that "we maj^ 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 available energy." As 

 Armsby found one gram of digestible matter from 

 timothy hay to be equal to 3.62 Calories of available- 

 energy, 13,000 Calories would equal 7.92 pounds of 

 digestible matter from this source. This would be 

 the same as 7.4 pounds for a 1,000-pound animal. 

 (See method of calculation in Chapter XIX.) 



