56 



PRINCIPLES OF FEEDING FARM ANIMALS 



The preceding remarks refer to total feed components in the 

 corn plant, and not to its digestible components. Digestion trials 

 trials have shown that the digestibility of plants in general decreases 

 as they grow older. The following table of results obtained in 

 American trials will show the average digestion coefficients of 

 green dent corn fodder cut at different stages of growth : 



Digestion Coefficients for Green Dent Fodder Corn 



While there was no material change in the digestibility of the 

 dry matter of the corn,, a marked decrease is noticeable in the digesti- 

 bility of the crude protein, fiber, and fat with the greater maturity 

 of the fodder. The digestibility of the nitrogen-free extract, on the 

 other hand, remains nearly stationary at the different stages of the 

 growth, and the main increase in feed components falls on this 

 constituent. In general, the decrease in the digestibility of the 

 feed components given is not sufficiently high to affect the large 

 increase in the yield of the components with the advancing age of 

 the plant, so that the yields of total digestible components will be 

 greater at maturity or directly before that time than at any earlier 

 stage of growth. Hence we find that the general practice of 

 cutting corn for forage or for the silo at the time when it is in the 

 roasting-ear stage or beginning to harden is in accord with our 

 best knowledge of the subject. 



Alfalfa. The changes in the composition of alfalfa during its 

 growing period have been studied by several stations. The average 

 results obtained for three cuttings at the Ontario Agricultural Col- 

 lege are given below. 



Composition of Alfalfa Cut at Different Stages of Growth, in Per Cent 



Compilation by Lindsey and Smith, Massachusetts Report, 1911. 



