162
Animal Nutrition Problem in Bengal
a case of deficient supply but of the barest need
of subsistence. The matter is further complicated
on account of the fact that the feeding of rice
straw is followed by certain complexities in
which almost all the essential nutrients suffer
from faulty assimilation.
THE GENERAL FEEDING VALUE OF RICE STRAW
A short-term feeding trial conducted at Karnal
(Punjab) suggested that rice straw when fed
with concentrate was superior to wheat straw
and was as good as jowar (sorghum). Later on
when work on a more comprehensive scale was
undertaken in Bengal, it was revealed that under
rice straw feeding not only the assimilation of
more essential nutrients like protein, lime,
phosphorus and potash was generally interfered
with, but in some regions, specially in saline
tracts, even other minerals suffered from disturbed
equilibrium. The Animal Nutrition Section, Bengal,
started under the grant of the Imperial Council
of Agricultural Research, carried out these ex-
periments when the present author was in charge
of it. The work was directed towards the examina-
tion of the existing food sources in order that an
economic formula of rationing might be devised
in due regard to quality and quantity of feed.
The first step towards it was to study how these
foodstuffs behaved within the animal system
and what were their specific characters for or
against proper nutrition. The work followed
broadly on two specific lines, one in reference
to the direct practical problems and the other
of more technical nature mainly arising as a
corollary towards the solution of many such
problems. This note deals with the former
aspect.
Protein. It was found that when the straw
was fed alone, there was an uneconomic wastage
of protein fraction which was least digested (re-
maining largely on the negative side), but when
supplemented with cake or concerntrates. the
digestibility and assimilation of protein were
remarkably increased. This was also the case
with the bulk of organic nutrients.
Phosphorus. In the case of phosphorus the
actual content is initially low and even this is
of doubtful availability.
Lime. In the case of lime, although the amount
ordinarily present is apparently more than
adequate from maintenance standpoint, the level
necessary for ensuring a favourable or positive
equilibrium is much higher than in many other
straws and green fodders. There appear to be
four factors responsible for this complication,
viz. (1) presence of oxalic acid and possibly
other allied substances which prevent the solubility
of lime, without which assimilation cannot
proceed, (2) high fibre content, (3) high potash
content and (4) complete absence of vitamin.
Potash. As straw contains a very large per-
centage of potash, a very large potash ingestion
(far more than is necessary) is an inevitable
accompaniment of rice straw feeding; but the
puzzling factor is that, in spite of such heavy
ingestion, more potash is excreted through faeces
and urine than is supplied in the feed. The
result is that when the data are measured on
a balance sheet, a negative balance for potash
is recorded. In actual fact the excess potash
is drained out from body resources. There
are indications that in this phenomenon the
nature and quality of cake and possibly other
concentrates play a significant role. Thus when
the straw was fed with linseed cake, the attain-
ment of a positive balance between intake and
outgo was a usual feature, but when mustard
cake (which is the main concentrate in these
parts) was fed, there was a general tendency
to a negative balance in spite of the fact that the
potash ingestion was distinctly higher (in some
cases 60 per cent over the other). In a recent
trial the combination of til or sesame cake has
also exhibited a similar feature.
Soda, chlorine and magnesia. So far reference
has been made to the more essential nutrients
such as lime, phosphorus and potash which have
recorded disturbed equilibrium under rice-straw
feeding. It has since been found from more
recent work that the straws specially from saline
belts (and in some cases from non-saline areas
also) have in addition new complexities. Thus,
with Barisal straw (from saline tract) chlorine
recorded negative balance in spite of feeding
common salt, while in the case of another saline
tract of Diamond Harbour (District 24 Parganas),
magnesia, soda and chlorine all exhibited adverse
equilibrium in spite of the fact that all these
components were more than adequately provided.
It is just possible that some of these features
are endemic in respect to certain regions.
Proper utilization of straw. The straw while
serving as a roughage, its main function is to
supply energy. Here also the most efficient
utilization occurs when it is supplemented with
cake. It is a fact that an unbalanced food is