18 BULLETIN 459, U. S. DEPARTMENT OF AGRICULTURE. 



Requirements for the production of 1 pound of milk. 



Fat in milk. 



Requirements. 









Digestible 



Net energy 





protein. 



value. 



Per cent. 



Pounds. 



Therms. 



2.5 



0.041 



0.19 



3.0 



.043 



.21 



3.5 



.045 



.24 



4.0 



.049 



.27 



4.5 



.052 



.29 



5.0 



.055 



.32 



5.5 



.058 



.34 



6.0 



.061 



.36 



6.5 



.064 



.39 



7.0 



.068 



.41 



REQUIREMENTS FOR WORK. 



Since the horse (or mule) is the usual working animal in the United 

 States, consideration will be limited to this animal. 



There is on record a considerable amount of data as to the rela- 

 tion between the work performed by the horse and the amount of 

 energy necessary to be supplied in the feed. Where large numbers 

 of horses are kept and the work is relatively uniform in amount, it 

 is possible to make fairly satisfactory computations from these data, 

 although the method is somewhat complicated. The amount of work 

 required of farm horses, however, is so varied in amount and kind 

 and so difficult of measurement or estimate as regards amount, that 

 it is scarcely practicable to base the calculation of rations upon it. 

 The table on pages 11-13 probably shows with at least a fair degree 

 of accuracy the relative values of different feeding stuffs as sources of 

 energy for work production, while the amount to be fed will ordi- 

 narily be based upon the observation of the feeder rather than upon 

 arithmetical calculations. As a sort of general average, however, 

 Kellner recommends the following rations for a 1,000-pound horse, 

 the amounts stated including the maintenance requirement: 



Requirements of the working horse. 



For light work 



For medium work 

 For heavy work... 



Digestible 

 protein. 



Net energy 

 value. 



Pounds. 

 1.0 

 1.4 

 2.0 



Therms. 

 9.80 

 12.40 

 16. 00 



DRY MATTER IN RATIONS. 



The total volume of feed which an animal requires, although 

 rather variable, has its limits. In computing rations the most con- 

 venient indication of the bulk of the feeds is the percentage of dry 



