42 



FIXING RATIONS ON THE BASIS OF INTERNA!. AND EXTERNAL 



MUSCULAR WORK. 



It was shown in connection with the above tests that a ration suited 

 to the performance of any kind of work can be calculated on the basis 

 of the nutritive material and energy required for maintenance plus 

 that needed for the work performed, though the method is too involved 

 to discuss in detail. Thus on the basis of experiments and observa- 

 tions it was calculated that a horse weighing 1,100 pounds requires for 

 maintenance 7.056 pounds of true available nutrients. Similar calcu- 

 lations were made for a horse working with or without harness and 

 wagon on a level and going up or down an incline at different gaits. 



It was found that the amount of total nutrients required increases 

 with the increased speed; furthermore, a greater amount is required 

 in climbing an incline than for forward progression on a level. In 

 descending a gentle incline a much smaller amount of nutrients is 

 required than in climbing the same incline, and as compared with the 

 motion of forward progression there is also a saving in the amount of 

 nutrients needed. In general, it was found that the energy expended 

 was less than in traveling on a level, provided the incline was less than 

 5° 45'. At this point it was equal to the amount expended in travel- 

 ing on a level. If the incline was greater, energy was required to 

 keep the body from descending too rapidly and the expenditure was 

 greater than on a level. 



SUMMARY. 



Some of the principal deductions noted in this bulletin follow; the 

 conclusions which have been drawn for horses applying with equal 

 force to other animals of the same group, such as asses and mules. 



Horses, like other animals, require a definite amount of nutrients 

 and energy per 1,000 pounds live weight for maintenance, and an 

 extra amount, chiefly energy -^delding nutrients, for muscular work, 

 the amount being proportional to the character and amount of work 

 performed. 



The amount of nutrients required increases with the amount of work 

 done and with increased speed. More energy is required for climb- 

 ing an incline than for traveling on a level. In descending an incline 

 of less than 5° 45' less energy is required than in traveling on a level. 

 If the incline is greater than 5° 45', more energy is expended (to pre- 

 vent too rapid descent) than in walking on a level. 



The ration should consist of concentrated and coarse feeds. The ratio 

 by weight of coarse fodder or bulky feed to concentrated feed in the 

 ordinary ration has been found to be about 1:1. Crude fiber may 

 perhaps be fairly considered as the characteristic constituent of coarse 

 fodder. The ratio of crude fiber to protein in the average of a large 

 number of American rations has been found to be about 2:1. 



1.70 



