260
Nutritive Values of Different Parts of Napier Grass
[XVII
It is noted here that the coarser stem has the largest percentage of organic matter (96.7 per
cent), chiefly fibre (38.6 per cent) and nitrogen.free extract (56 per cent); as a matter of fact these
constitute such a large part of the organic make-up that very little is left for the other nutritive
components specially protein (1.61 per cent) or fat (0.47 per cent); much of the nitrogen-free extract
is however embedded in the hard integument which prevent its full assimilation. The coarser stem
is also very poor in lime (0.12 per cent), a characteristic of the whole plant (0.29 per cent CaO). The
leaves contain the largest percentage of protein (8.01 per cent) and lime (0.51 per cent), while the
softer stem stands second in protein content but first in soluble ash (4.82 per cent), potash (2.33
per cent) magnesia (0.46 per cent), phosphorous (0.86 per cent) and chloride (0.31 per cent). Taken
on the whole the more useful components exist in larger percentages in the leaves and softer stem.
This aspect is more clearly demonstrated on the basis of proportionate distribution of nutrients
shown in the last three columns of Table VII. It will be noted that per 100 parts of whole plants
(leaves, softer stem and coarser stem) about 79 parts of organic matter are distributed between the
leaves (33.3 parts) and the softer stem (46.0 parts) leaving nearly 21 parts for the coarser stem.
Protein and ether extract run parallel, being divided between 6 to 7 parts in the coarser stem, 31
to 33 parts in the softer stem and 60 to 63 parts in the leaves. Though the actual fibre content is
highest in the coarser stem, it only forms 22.3 parts for 100 in the whole plant. This is due to the
fact that the entire coarser stem does not constitute more than one-fifth of the whole plant.
Of the soluble ash 90 parts are divided between the leaves (35.3 parts) and the stem (54.5 parts)
leaving 10.2 parts for the coarser stem. The leaves also contain most of insoluble ash (57 parts) as
compared to 34.2 parts in the softer stem and 8.8 parts in the coarser stem.
Of individual minerals the leaves have 60.1 parts of lime, the softer stem 31.6 parts and the
coarser stem 8.3 parts.
The softer stem have the largest share of magnesia, potash, phosphate and chlorine, viz. 55.0,
58.6, 56.4 and 63.2 respectively. Contrary to expectation phosphate has been found highest (both
in composition and distribution) in the softer stem and less in the leaves.
Taking all facts into consideration the coarser stem, if rejected, will account for a loss of 20 parts
organic matter, about 8 to 9 parts of lime, 14 parts of phosphate, 26 parts of soda and 7 parts of
potash. The animal is generally inclined to reject much of this part.
The object of this work was to ascertain whether in feeding Napier grass it would be more
economical to put the whole plant to the feeding trough or to discard the coarser part. The results
suggest that the coarser part is poor in composition with respect to all components except fibre and
nitrogen-free extract. But on account of its coarse and tough integuments it is bound to involve
an expenditure of a large amount of energy in the work of digestion. It is likely that its exclusion
from the diet might prove more economical than its inclusion because of the saving of energy and
because the diet would be more efficiently digested the loss of essential minerals would be negligible.
SUMMARY
1. The composition of the coarse stem, the rest of the stem, and the leaves of Napier grass, a
1 ft., 2 ft., 3 ft., 4 ft., 5 ft. and 6 ft. high grown in Bengal was assayed and is discussed.
2. It is suggested that the coarse part of the stem is not worth feeding.