Available Energy in Typical Nutrients 175 



Total heat value Per cent of Available heat Comparative 



of 1 gram of loss in urine value for 1 gram available heat 



digested and gases- digested value when 



organic matter methane organic matter starch is 100 



cal. Percent cal. 



Starch 4183 10.lt 3760 100 



Extracted straw.. 4247 14. f 3651 97 



Molasses 4075 10.4 3645 97 



Meadow hay 4480 18.7 3640 97 



Oat straw 4513 16.9 3747 100 



Wheat straw 4470 25.6 3327 88 



Gluten 6148 19.3ft 4958 132 



Peanut oil 8821 8821 235 



t Loss wholly from methane. ft Loss wholly in urine. 



The available energy is seen in the total energy of 

 the digested organic matter less that which is lost in 

 the urine and from fermentations which produce the 

 unoxidized gases. 



These figures show the energy or heat furnished to 

 the animal by the different materials after deducting 

 losses. They also represent the heat production when 

 the substances were fed in a maintenance ration, 

 and as Rubner has demonstrated that the heat lost 

 from the animal that is eating just a maintenance 

 ration is, a measure of the animal's use of food, 

 these values show what the different substances were 

 worth for maintenance purposes. It appears that 

 in these investigations the sugars of molasses, ex- 

 tracted cellulose and the material digested from the 

 coarse foods containing much cellulose and gums sup- 

 plied practically the same available energy to the 

 animal that starch did, wheat straw excepted. 



Relative production values of the different nutrients, 

 - -If we calculate the fat -forming value of protein and 



