CHEMICAL COMPOSITION. 



367 



of the several constituents of alfalfa hay digested, first crop, 

 three stages of growth, calculated to water-free basis: 



Here it is seen that the digestible protein diminishes marked- 

 ly as the alfalfa matures, while the digestible carbohydrates in- 

 crease. A calculation of the nutritive ratio in each case brings 

 out this fact in a concise way. The nutritive ratio of a feed 

 is the ratio of the energy of the digestible nitrogenous sub- 

 stances to the energy of the digestible non-nitrogenous sub- 

 stances. Making the necessary calculations, the nutritive ratios 

 are found to be as follows: First stage, 1 to 3.11; second stage, 

 1 to 3.49; third stage, 1 to 4.38. These are all narrow ratios 

 but widen as the alfalfa matures. 



A full appreciation of the feeding value of alfalfa cannot be 

 had without comparisons with other feeds. The average per- 

 centage of digestible constituents in certain well known feeds is 

 shown in the following table: 



It will be seen that alfalfa cut at the first stage gave a hay 

 that had a higher percentage of digestible protein than any of 

 the feeds named in the table, and that the digestible carbohy- 

 drates (fiber plus nitrogen-free extract) of alfalfa compare favor- 

 ably with those in the feeds cited, and in some cases exceed 

 them. The nutritive ratios bring out clearly the value of alfalfa 

 as a source of protein, and its great availability in balancing 

 rations. 



Many analyses of alfalfa made at other experiment stations, 

 with such digestive experiments as have been performed, show 

 the same general results as are exhibited in the foregoing. The 

 earlier cuttings are richer in protein, but a high and nearly 



