136 AGRICULTURE. 



2. Calculating the Heat-producing Material 

 in Corn. — In the table the ether extract in corn 

 (all analyses) is given as 4.3 ; multiplying by 2.4, 

 the product is 10.32 pounds. The carbohy- 

 drates are given as 66.71 pounds. Adding the 

 heat value of the ether extract (10.32 pounds) 

 to the carbohydrates given, the sum is 77.02 

 pounds, the total heat-producing material in 100 

 pounds of corn. 



I. Analysis of Feeding Stuffs. 



1. The amount of carbohydrates, of ether ex- 

 tract, and of protein in a given food has been 

 ascertained by repeated analyses. These 

 amounts vary in different samples of the same 

 kind of food, but the average results of a large 

 number of analyses are used as a basis for the 

 tables. 



2. Per cent, of Digestibility. — -But the (7w^//«/ 

 of nutrients contained in a food is not enough 

 to know. One must know what per cent, of it 

 is available — that is, what per cent, of it the ani- 

 mal in a given condition is able to digest and 

 assimilate. Many experiments* have been and 

 are being made to find out the per cent, of these 

 nutrients actually digested. Some of the results 

 are eiven in table III. 



II. Wolff-Lehmann Feeding Standards. 



I. A Balanced Ration. — Not only is it essen- 

 tial to know the amount of digestible protein, 



* Henry's Feeds and Ftediiig, pp. 26, 27. 



