71 



FIXING RATIONS ON THE BASIS OF INTERNAL AND EXTERNAL 



MUSCULAR WORK. 



Zuntz believed 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 per- 

 formed. The calculations are simplitied by using- the figures for "true 

 nutritive value " given in the table above. On the basis of his experi- 

 ments and observations he has calculated that a horse weighing 500 

 kilograms (1,100 pounds) requires for maintenance 3,201 grams (7.056 

 pounds) of true available nutrients. The amounts of true available 

 nutrients and the energy required for the performance of work of dif- 

 ferent kinds and under different conditions by a horse weighing 500 

 kilograms (1,100 pounds), with a harness weighing 20 kilograms (11 

 pounds) are shown in Table 10. The value of total nutrients repre- 

 sents the protein + the carbohydrates + the fat X 2.4. Fat is multi- 

 plied by 2.4, .since, as stated on another page (68), it ^delds, according 

 to Zuntz, that much more heat per gram than protein or carbohydrates 

 when burned in the })ody. 



Table 10. — Available nutrients and energy needed for different kinds of work. 



a As compared with forward progression. 



