208 PRINCIPLES OF FARM PRACTICE 



Carbohydrates serve the same purpose as fats; both are 

 energy-producing feeds. But a given amount of fat produces 

 about two and one-fourth times as much energy as the same 

 amount of carbohydrates. In order to simplify calculations 

 in the study of rations, it is customary to reduce fats to their 

 carbohydrate equivalent, by multiplying the amount of 

 digestible fat by two and one-fourth. The product obtained 

 is added to the amount of carbohydrates, and the sum will 

 give the total energy-producing material in terms of carbo- 

 hydrates. 



With these definitions in mind we will pass to their appli- 

 cation. Two things should be taken into consideration: the 

 composition of feeding-stuff, and the rations, called standard 

 rations, that have been proved by experience and scientific 

 investigation to be the most satisfactory for the various 

 classes of farm animals. The problem is to secure for a 

 particular animal a combination of feed material that will 

 as nearly as possible fulfill the requirement of the standard 

 ration. Such a combination should take into consideration 

 the composition of the various substances used by animals 

 as feed. All kinds of feeding material have been carefully 

 analyzed and the results placed in tables for reference. In 

 the appendix of this book is a table compiled from such 

 sources, giving the composition of many common feeds. 



Standard rations. A standard ration is a certain com- 

 bination of feeds adapted to a particular class of animals. 

 Each standard ration has been developed through many 

 years of experience in feeding farm animals, and through a 

 study of experiments designed to show the effects of various 

 combinations of feeds on different farm animals. 



While the standard rations are by no means perfect, they 

 furnish the best guide now available for intelligent feeding. 



