124 PROGRESSIVE POULTRY CULTURE 



seen that there are two ways of expressing the value 

 of a feedrstuff. First, the quantity of heating power 

 contained in a given weight of the feed-stuff may be de- 

 termined. This is termed its "fuel value" and is ex- 

 pressed in Cailories or "heat units." A Calorie signi- 

 fies the quantity of heat required to raise the tempera- 

 ture of on'e pound of water fooir degrees Fahrenheit.. Ex- 

 pressed in terms of work this i<s> equivalent to the power 

 necessary to lift one ton vertically 1.53 feet. The fuel 

 value of the nutrients is calculated according to the 

 following method: 



One pound of digestible fat in a food is considered 

 to have a heating power of 4220 Calories. One pound 

 of either digestible carbohydrates or piroteidB* is con- 

 sidered to have ai heating value equivalent to 1'860 Cal- 

 ories. 



To calculate the beating value of one pound of In- 

 dian Corn (Maize) for example, proceed as follows: 

 Reference to Table A shows that in one pound of 

 corn there are .0714 of a pound! of digestible protein 

 and .6612 of a pound of digestible carbohydrates. Add- 

 ing these two amounts gives .7326 of a pound of nutri- 

 ents and multiplying this sum by 1860 gives 1362.6 

 Calories. The digestible fat in one pound of corn is 

 found to be .0497 of one pound, which multiplied by 

 4220 gives a result of 209.7 Calories. Adding 1362.6 

 to 209.7 gives a total of 1572 Calories, which expresses 

 the fuel value or quantity of heating power contained 

 on the average in one pound 1 of corn. 



Secondly, the quality of a feed-stuff may be meas- 

 ured and expressed by the proportion of its nitrogenous 

 to its non-nitrogenous digestible nutrients, which is 

 termed its "nutritive ratio." 



As the fats have two and one-fourth times the 

 heating power of the carbohydrates (starches, sugars, 

 fibres), the weight of the fatty nutrients is multiplied 

 by two and one-fourth to bring all the non>-nitrogenous 

 nutrients to one level of value in) calculating the ratio. 

 Take again for example the case of Indian Corn. Re- 

 ferring to Table A, one pound of Corn is found to have 



