THE PRmCIPLES OF FEEDING 

 FARM ANIMALS 



CHAPTER I 



THE CHEMICAL COMPOSITION OF FEEDINGSTUFFS 



In order for the student of stockfeeding to acquire a 

 thorough understanding of the subject, it is necessary for him 

 to have a general knowledge of the chemical composition of 

 feedingstuffs. The composition of feedingstuffs is quite 

 variable, and their feeding value depends to a large extent 

 upon their composition. When asked concerning the value 

 of a feed with which one is unfamiliar, one usually refers to 

 its chemical composition, although other factors also have 

 considerable influence, as will be explained later. 



Elements. — Chemistry teaches that all vegetable and 

 animal substances are composed ultimately of chemical 

 elements. Of the 83 chemical elements now known, ap- 

 parently only 12 are of importance from the standpoint of 

 stockfeeding. These are as follows : carbon, hydrogen, 

 oxygen, nitrogen, phosphorus, potassium, calcium, sulphur, 

 sodium, magnesium, chlorine, and iron.^ Other elements, 



^ Dr. C. G. Hopkins, in "Soil Fertility and Permanent Agriculture," 

 presents the following memory key to the elements essential to plant life : 

 "C. Hopk'ns' CaFe, Mg, " if "Mg" stands for "mighty good" and "I" 

 is omitted for modesty. If the student then remembers that all animals 

 require salt, NaCl, he has a list of the important elements. 

 B 1 



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