108 AGRICULTURAL EXPERIMENT STATION. 



The differences in total amount of nutrients as shown, are easily 

 seen. In order to express the relation in quantity of the digestible 

 protein to the digestible non-nitrogenous material, there is given in 

 the last column of the following table what is called the nutritive 

 ratio. 



As an example of how this ratio is calculated, the standard ration 

 for a milch cow is selected. This calls for 2.5 lbs. digestible pro- 

 tein, 12.5 lbs. digestible nitrogen-free extractive matter and fiber, 

 and .40 lbs. digestible fat. 



The fat has a greater value per pound than sugar or starch, and 

 in order to reduee the figures to the same basis, we multiply the 

 percentage of fat by 2|, because for heat production a pound of fat 

 is equal to 2| pounds of the carbohydrates. 



12.5-i-(.40X2|) = 13.5. 13. 5 -I- 2. 5=: 5. 4. 



The nutritive ratio is therefore 1 : 5.4. 



