MAINTENANCE RATIONS 309 



than is that for maintenance, for two reasons: (1) Because 

 the quantity of available nutrients which must be eaten 

 is so small that this ration may be wholly or mostly made 

 up of bulky materials such as corn fodder and hay; (2) 

 because investigation has demonstrated that mere main- 

 tenance demands a comparatively small amount of pro- 

 tein and so this ration may have a wide nutritive ratio 

 such as pertains to the nutrients of the more common 

 farm products. 



AtA.INTENANCB RATION FOR BOVINES 



409. Various investigations concerning maintenance 

 needs. — ^Experiments, having for their object a determina- 

 tion of the daily quantity of nutrients necessary to simply 

 maintain animals of this class, were conducted by Henne- 

 berg and Stohman with oxen as long ago as 1858. A num- 

 ber of rations were fed and the conclusions which were 

 reached were based upon the amount of food digested, 

 the gain or loss of nitrogenous tissue by the animals, 

 their weights, and general appearance. The average daily 

 quantities of digestible nutrients which appeared to be 

 sufficient to maintain a 1,000-pound ox without growth or 

 loss was approximately 8.2 poimds, of which .53 pound 

 was protein, the whole having an energy or heat value of 

 not far from 15,000 calories. Because of the high tem- 

 perature of the stalls used in the above-named experi- 

 ments, Wolff estimated later that for winter feeding the 

 standard should be 8.9 pounds of digestible nutrients, of 

 which .7 pound should be protein, the energy value being 

 approximately 16,000 calories, and for a long time 

 Wolff's figures were published as the standard main- 

 tenance ration. 



