CHEMICAL COMPOSITION OF FEEDING STUFFS 



57 



The results show a decrease in the percentage of water and, 

 therefore, in the succulence of the crop. In order to show the 

 changes in chemical composition, the analyses have been calculated 

 to water-free substance, and it is seen that as the plant matures the 

 percentages of ash, crude protein, amides, and fat decrease; as 

 the stems grow hard and woody, the fiber contents of the plant in- 

 crease, and the percentages of valuable feed components decrease in 

 proportion, except that of nitrogen-free extract, which does not 

 change materially. If we now consider the digestibility of the dif- 

 ferent cuttings of alfalfa, we have the following average figures 

 obtained in digestion experiments conducted at Ontario Agricul- 

 tural College : T 



Digestion Coefficients for Alfalfa 



There is a decided decrease in the digestibility of the total dry 

 matter and of all components as the plant approaches maturity ; the 

 decrease is especially marked between the second and third cuttings. 

 If the total digestible matter obtained in the three crops be calcu- 

 lated on the basis of the figures just given, it will be found that 

 the amounts of digestible matter secured in the later cuttings are 

 considerably lower than those found in the earlier ones. In the 

 Canadian experiments referred to, the three cuttings gave, on the 

 average, the amounts of green alfalfa and digestible matter shown 

 in the table : 



Calculated Yields of Dry Matter and Digestible Matter of Green 

 Alfalfa Per Acre in Pounds 



There was a decrease of 18.8 per cent, or nearly one-fifth, of the 

 digestible matter during the two weeks' interval between the last 

 two cuttings, calculated on the yields of the second cutting. 

 T Report, 18U9, p. 37. 



