82
Nutritive Value of Maize
Husk
[Vol. XVIII, Part I]
wheat bran but much lower than that of rice-bran. The husk contains nearly the same amount of
crude fibre as the brans but is significantly richer in nitrogen free extract, being twice as rich as rice¬
bran. The figures for calcium and phosphorus in the two samples of brans are not available, but
from data of other samples [Sen, 1946] it is apparent that, unlike the husk, the two brans are rich
sources of phosphorus, though their calcium content is definitely poorer than that of the husk.
METABOLISM OF MAIZE-HUSK
For reasons stated later, this investigation had to be carried out in two experiments :
EXPERIMENT I
The object was to study the maximum quantity of maize-husk taken by cattle when given free
access to it, and with maximum consumption of husk and wheat-bhoosa fed ad lib to determine (a)
the digestibility coefficient of the whole ration as well as of maize-husk and (b) nitrogen calcium
and phosphorus balances. Four adult healthy kumauni bullocks of average live weight of 300 lb.
were selected for experiment. In a preliminary trial, an attempt was made to assess the maximum
quantity of the husk the animals would consume. They seemed to relish the stuff and the daily
consumption varied between 4 to 5 lb. per animal. In the course of about a week, however, con-
sumption gradually fell. The method of feeding was then changed by mixing finely ground common
salt with the husk. This improved the consumption and just before the experimental trial it was
stabilized at about 3.5 lb. During the trial each animal was given 4 lb. of the husk mixed with one
ounce of common salt, the residue left over was weighed and recorded. After the consumption of
the husk, which was placed before the animals at 9.30 a.m. and the residue removed after about 3
hours, weighed quantity of wheat-bhoosa in excess of the actual requirement was offered. A record
was also maintained of the residue left of the wheat-bhoosa. This ration was fed for a preparatory
period of 15 days, after which 24 hourly collections were made of excreta for 10 days to determine
the digestibility and balances of nitrogen, calcium and phosphorus. During the feeding trial, the
animals were frequently weighed. The weight at the end of the trial revealed that all the animals
suffered a mean loss of weight of 7 lb.
Food consumption. In Table II is given the consumption on dry basis of individual items of
the ration per head per day, as also the total dry matter consumption per 100 lb. live weight. The
data in Table II show that the average daily consumption of maize husk in three out of four animals
was a little over 1400 gms. in one animal it was slightly less than 1200 gms. The daily consumption,
when averaged for the four animals works out at 1354.6 gms. maize husk per animal per day. This
high intake of husk supplemented simply by common salt seemed to have seriously affected the con-
sumption of wheat-bhoosa which was as low as 66.8 gms. per animal per day. The lowered intake
of roughage was reflected in the total dry matter consumption per 100 lb. live weight. Considering
that the average capacity of consumption of dry matter, under maintenance condition of an adult,
should ordinarily approximate 900 gms. per 100 lb. live weight, the average intake of 672.8 gms. dry
matter indicates that the actual consumption is about 25 per cent below the expected normal. It
would be of interest to trace the reasons for this depression in intake when the feeds were offered
freely. One of the possible factors limiting the optimum intake may be the physical effect of swelling
which maize-husk may undergo in the rumen. But perhaps a more potent factor is the unusually
low phosphorus content of the husk. It is well known that one of the earliest physiological distur-
bances produced by phosphorus deficiency is depression in appetite [Tjeiler and Green, 1932]. The
data presented later seem to justify this contention.
RESULTS OF METABOLISM TRIALS
In Tables III and IV are detailed the composition of the feeding stuff used in the experiment
and the consumption and excretion of various nutrients and their digestibility coefficients. The
balances of nitrogen, calcium and phosphorus are shown in Table V. The significance of these data
on metabolism will be discussed later.