552 NUTRITION OF FARM ANIMALS 



performance of one kilogram meter of work of ascent, the two 

 following equations may be formulated : 



x + 0.004395 y = 0-4035 



x + 0.107041 y = 1.0795 cals. 



From these equations the values of x and y can be computed 

 to be as follows : 



x = 0.3746 cals. y = 6.5856 cals. 



Since one kilogram meter is equivalent to 2.344 cals., it fol- 

 lows that the net efficiency in the work of ascent was 

 2.344 -T- 6.5856 = 35.73 per cent. In effect, the net efficiency in 

 work of ascent is computed by deducting from the total energy 

 output the amounts expended for maintenance and for hori- 

 zontal locomotion and comparing the remainder with the meas- 

 ured work of ascent. The results given in the previous para- 

 graph for the energy expended in locomotion were computed 

 according- to this scheme. 



654. Work of draft. The net efficiency in draft was com- 

 puted by a similar method. The tread power was set nearly 

 horizontal. On the average of sixteen trials the total energy out- 

 put in excess of maintenance per kilogram live weight and per 

 meter traveled was 1.5021 cals., the work of ascent 0.005115 

 kilogram meters and the work of draft 0.153127 kilogram meters. 

 Letting z equal the energy expended in the performance of i 

 kilogram meter of work of draft, the following equation may 

 be formulated: 



x + 0.005115 y + 0.153127 z = 1.5021 cals. 



Substituting average values for x and y, the value of z is 

 7.143 cals., equivalent to a net efficiency of 32.84 per cent. 



655. Correction for speed. In experiments made at a walk 

 it was found that the expenditure of energy per meter increased 

 materially as the speed increased, as is illustrated by the aver- 

 ages already cited (652) and is shown more fully in a succeed- 

 ing paragraph (663). In computing the efficiency of work of 

 ascent or draft, it is necessary to take account of this fact. 

 The method of doing so is a method of approximation, the de- 

 tails of which need not be gone into here. 1 



1 Compare Armsby, Principles of Animal Nutrition, pp. 507-508. 



