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 
Nitrogen- 
‘ No. of D Crud ‘ 
Stage of growth Coals aaaniee seetein Fiber : Laat Fat 
Immature..... 14 68 66 65 71 86 
In milk........ 17 70 62 64 77 76 
Glazing........ 9 67 54 51 75 78 
Mature....... 23 69 54 59 75 75 
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 marked 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 
Composition of water-free substance 
Moisture Nitrogen- 
Ash Protein | Fiber free Fat Amides 
extract ‘ 
Buds forming...| 81.53 | 11.63 | 18.46 | 27.56 | 39.36 3.06 4.09 
Medium bloom.| 78.48 9.60 | 15.44 | 33.58 | 39.08 2.40 2.23 
Full bloom..... 74.50 8.35 | 18.12 | 37.64 | 39.36 1.94 1.86 
* Compilation by Lindsey and Smith, Massachusetts Report, 1911. 
