Investigations Concerning the Horse. 263 



maintenance the following net nutrients must be supplied in the 

 daily ration : 



Net nutrients 



For 20 miles locomotion (0.134x20) (4O2) 2.68 Ibs. 



For 5,280 f t.-tons draft (1. 157 x 5,280) (4O2) 6. 11 Ibs. 



For maintenance (exclusive of work of mastication and 

 digestion) (393) __ ---- 2. 43 Ibs. 



Total 11. 22 Ibs. 



If 10 Ibs. of meadow hay and 10 Ibs. of oats be chosen for the basal 

 ration, the computations would be as follows: (403) 



Net nutrients 



Total requirement 11. 22 Ibs. 



In 10 Ibs. meadow hay (0.182 Ib. xlO) 1.82 Ibs. 



In 10 Ibs. oats (0.491 lb.xlO)..._ 4.91 Ibs. 



Total basal ration. _ 6 . 73 Ibs. 



Remainder to be supplied 4.49 Ibs. 



"We may supply the lacking 4.49 Ibs. of net nutrients by adding 

 6.4 Ibs. corn (4.49 Ibs. -^-0.703 Ib., net nutrients in 1 Ib., =6.4 Ibs.). 

 Hence 10 Ibs. of meadow hay, 10 Ibs. of oats, and 6.4 Ibs. of corn will 

 furnish a satisfactory ration for an 1100-lb. horse when drawing a 

 load of a ton 20 miles on a level road at the rate of 2.9 miles per 

 hour. 



405. Relation of speed to work. According to Fourier, 1 a good 

 horse, with the best load for each speed, will perform the maximum 

 amount of work at the speed of about 2 miles per hour. Taking this 

 maximum as unity, he gives the following as the probable value of 

 work performed at other speeds : 



Miles per hr. Daily work Miles per hr. Daily work 



1.25 0.69 6.25 0.68 



2.00 1.00 7.50 0.51 



2.50 0.99 8.75 0.33 



3.75 0.94 10.00 0.18 



5.00 0.83 11.25 0.07 



The data show that the horse is at its best for drawing loads when 

 moving at the rate of from 2 to 2.5 miles per hour. As the rate of 

 speed increases beyond this, the amount of energy which the horse 

 can devote to drawing the load grows rapidly less, until when 11.25 

 miles per hour is reached less than 0.1 of the maximum work can 

 be performed. 



1 Thurston, The Animal as a Machine and a Prime Motor, p. 52. 



