It seems still necessary that an explanation of the terms used 

 should accompany all discussions of foods and fodders, and we 

 rnay therefore be pardoned for repeating it here. 



The value of a fodder in the main depends upon the amount 

 and relative proportions of four classes of constituents. These 

 are usually denominated by chemists as crude protein (nitrogen 

 multiplied by 6.25), ether extract, nitrogen-free extract, and fibre, 

 and on the accompanying plate are represented by red, yellow, 

 blue, and golden brown, respectively. 



Protein is the most costly and the most valuable constituent of fodders. 

 Protein substances contain nitrogen and are often called albumeuoids or flesh 

 formers. They are found in all parts of all plants and all animals, and are 

 important and indispensable constituents of lean meat, blood, and all inter- 

 nal organs. Since a large number of fodders are lacking in this class of 

 constituents, the amount of protein that a fodder contains is largely a meas- 

 ure of its value. 



Ether Extract is mainly composed of fats and oils, and is usually spoken 

 of as such. It is used by the animal as a heat producer or stored up in the 

 tissues of the body as surplus fat. For these purposes it is worth nearly two 

 and one-half times as much as starch, sugar, gum, and other carbhydrates. 



Nitrogen-Free Extract consists of those substances containing no nitro- 

 gen that are soluble in water and dilute acids and alkalies, it is mainly made 

 up of starch, sugar, and gum, and the whole class is often spoken of as carb- 

 hydrates. The function of these carbhydrates in the animal economy is 

 mainly that of heat and fat producers. 



Fibre 'is that portion of the plant not dissolved by the action of dilute 

 acids and alkalies. In composition it is a carbhydrate, and its function as a 

 fodder is the same as the other carbhydrates, but being less digestible is of 

 less value. 



The Nutritive Ratio is the ratio of the protein to the other three classes. 

 It is always expressed by the formula " as 1 : — " It is found by adding to 

 the digestible portion of the fibre and nitrogen-free extract two and one-half 

 times the digestible fat, and dividing the sum by the digestible protein. For 

 example, one hundred pounds of clover hay contain 7.82 pounds of digesti- 

 ble protein ; 40.25 pounds of digestible nitrogen-free extract and fibre, and 

 1.49 pounds of digestible fat. Two and one-half times 1.49 i his 



added to 40.25 makes 43. 98. and this divided by 7.82 gives 5.6. Clover hay, 

 then, contains one part of protein to five and six tenths parts of nitrogen-free 

 extract, fat and fibre, or as it is expressed, the nutritive ratio of cl< vi hay 

 is 1 : 5.6. 



As to the money value of the various constituents the Germans 

 have estimated that disgestible protein and fat are each worth tour 

 and one-third cents per pound, and that digestible carbhydrates 

 ire worth nine-tenths of a cent per pound. These figures are 

 much tod high for American fodders, especially for protein. 



Dr. Jenkins, (Ct. Exp. Station Bull., 96), has made an estimate, 

 based on the selling price of various concentrated foods, that pro- 

 tein is worth 1.6 fat 4.2 cents, and carbhydrat nts per 

 pound. On this basis, not including the fibre, the fodder produced 

 on an acre of our field corn (last line of Table III, and right hand' 

 figure of plates) would be worth S74. 13, while thefoddei need 

 on an acre of Evergr ugar (No. 41 of Table III and plates) 

 would be worth $24.31. These figures are evidently too high for 



rve to show the relative value of differ- 

 ent vari< 



In regard to the ash it is only necessary to state that while it is 

 in indispensabh itituent of foods, almost all fodd< mtain a 



sufficient amount and it may therefore be ignored in discussing 

 them. 



