306 PRINCIPLES OF FEEDIXd FARM ANIMALS 



cost. Thus in practical feeding operations, not only the 

 efficiency but also the cost of the rations must be considered. 

 In general, efficiency depends largely upon two general 

 classes of factors, one class concerning the ration itself, and 

 the other class concerning the animal which consumes the 

 ration. 



Among the factors relating to the ration itself are the 

 following : the physical composition, chemical composition, 

 digestibility, amount, and preparation of the ration. The 

 principal factors concerning the animal are : the species, 

 type and grade, age, capacity, temperament, and previous 

 treatment of the animal, the length of the fattening period, 

 and the temperature and other cHmatic conditions. 



The physical composition of the ration, i.e. the nature 

 of the feedingstuffs which make up the ration, is a large 

 factor in determining the efficiency. It is commonly known 

 that certain combinations of feedingstuffs are more efficient 

 for certain purposes than certain other combinations. For 

 example, a ration of corn and clover hay is more efficient 

 for producing gains than a ration of barley and clover hay, 

 although they both contain practically the same amounts 

 of digestible protein, total nutriment, and net energy. A 

 large part of the work of animal husbandry investigators 

 has consisted of a comparison of different rations in order 

 to determine what combinations of feedingstuffs are most 

 efficient for different purposes. Obviously, the stockfeeder 

 always should endeavor to feed a ration which will make 

 the production as efficient and economical as possible. 



The chemical composition of the ration determines its 

 efficiency to a large extent. A ration which is deficient in 

 any of its nutrients, or a ration which contains an excess of 



