66 Animal Husbandry 
trients in the food, usually known as the Wolff-Lehman method, 
and second, according to the energy value of the food, commonly 
known as the energy or Armsby method.! 
123. Wolff-Lehman method.— To illustrate the method of 
calculating a ration for a given purpose, we will assume the case 
of a horse weighing approximately 1000 pounds and at moderate 
work. From the discussion on food requirements for the horse, 
p. 71, we learn that the standard ration is as follows : — 
Dry-MatTEeR | PROTEIN CaRBOHYDRATES Fat | Ratio 
24.0 | 2.0 i 11.0 0.6 | 1:6.2 
Let us choose from Table 6 of the Appendix such foods as will 
supply the conditions. For a trial ration, we will take fourteen 
pounds of timothy hay, ten pounds of oats, and two pounds 
of bran. The digestible nutrients in these are calculated as 
follows :— , 
CaLcuLaTion oF Dry-Matrer anp DiceEstiBLE NUTRIENTS IN TRIAL 
Ration ror A Horse avr Mepium Worxk 
Timotuy Hay Grounp Oats 
In 100 In 14 In 100 In 10 
Pounds Pounds Pounds Pounds 
86.8 +100 X14 = 12.152 88.0 +100 X10 = 8.80. 
28 +100 X14 = 0.392 10.1 +100 X10 = 1.01 
42.4 +100 X14 = 5.936 52.5 +100 X10 = 5.25 
13+100x14 = 0.182 3.7 +100 X10 = 9.37 
In like manner, calculate the digestible nutrients in two 
pounds of bran and arrange the result in tabular form as 
follows :— 
1 Farmers’ Bulletin, No. 346, United States Department of Agriculture. 
