SCIENTIFIC SWINK FPJEDING 233 



into simpler products within a cell or organism. The process 

 goes on after the food is digested and taken into the system. 



Protein. — Nitrogen compounds that are used in producing 

 and maintaining the lean meat or muscle tissue and to a lesser 

 extent the bone tissue of the body. Bones also contain con- 

 siderable ash or mineral matter. 



Crude Protein. — Total nitrogen compounds (NX6H) or 

 what is frequently called protein. This includes the true pro- 

 tein and the non-protein. The latter cannot be used by the 

 animal as a substitute for protein. 



Factor of Waste. — When a pig is fed more than a certain 

 quantity of nutrients, especially protein, it does not use the 

 excess as economically in producing gains in live weight. The 

 portion lost on account of this less economical use is what is 

 here termed the factor of waste. An animal given too much 

 protein establishes a more or less pei'manent habit of waste. 



Feeding Standard. — A feeding standard is a statement of 

 the quantities of the various digestible nutrients necessary for 

 the development and maintenance of an animal. As the term 

 is used in this volume, it includes water and mineral matter. 



NATURE OF SWINE-FEEDING PROBLEM 



Swine feeding is a process of construction and maintenance. 

 As far as construction is concerned it is similar to the building 

 of a house. Certain amounts of different kinds of material are 

 necessary. The amounts of these vary considerably, being 

 large in some cases and small in others, but the materials that 

 are present in small amounts are just as important as those that 

 are present in large amounts. So it is with a hog and with 

 other animals. 



During the growing period of an animal both construction 

 and maintenance are required. As soon as a given amount of 

 body weight has been produced it has to be maintained and an 

 additional amount is being produced at all times during the 

 growing period. For the best results material must be 

 brought in that can be used by an animal in the building proc- 

 ess. An animal must make bone, lean meat or protein tissue, 

 and fat meat or non-nitrogenous tissue. 



It is true that an animal can substitute to some extent and 



