280
The Nutritive Value of Alkali-treated Cereal Straws
In period 2, the consumption of concentrate was reduced by 4 per cent.
Moreover, the crude protein content being about 35 per cent lower in alkali-
treated straw, the total nitrogen intake in period 2 was about 6 per cent
lower than that in period 1. In spite of the slightly lower intake of nitrogen
during alkali-treated straw feeding, the larger retention of this constituent
was the outstanding feature of the balance. The balance was over ten times
higher than in period 1. In period 1, out of 37.0 gm. of absorbed nitrogen,
about 97 per cent was excreted in the urine. On the other hand, in period
2, out of 30.6 gm. of absorbed nitrogen, only 57 per cent was rejected in the
urine. Obviously in period 2, the utilization of protein was considerably
augmented. A perusal of the nitrogen balance data given by Godden [1920]
reveals an identical picture, though he did not specifically discuss this point.
His data show that sheep consuming 24.18 gm. nitrogen from linseed cake
plus oat straw, excreted 4.9 gm. in faeces and 18.70 gm. in urine and thus
retained 0.56 gm. of nitrogen. The same animals, when fed with the linseed
cake and treated oat straw, out of the 23.78 gm. of nitrogen consumed, re-
tained 4.30 gm. and excreted 5.58 gm. in their faeces and 13.90 gm. in
their urine. Thus the retention actually increased about eight-fold.
The balance of calcium and phosphorus followed the same trend as
that of the nitrogen, i.e. when treated straw replaced the untreated straw,
the positive balance of these minerals significantly improved. In period
1, the animals were barely in calcium equilibrium. In period 2, the high
positive balance was due to a larger ingestion of calcium. This large
ingestion, as has already been pointed out in the earlier part of this paper,
was due to the presence of a higher percentage of this mineral in the
treated straw. In period 2, not only was the balance but the percentage
absorption was also definitely improved, viz. from 17 per cent in period
1 to 43 per cent in period 2. It is interesting to note also that, although the
level of phosphorus intake was lower in period 2, the percentage absorption
showed a definite improvement. It increased from 21 in period 1 to 29 in
period 2.
SECTION III.—The nutritive value of alkali-treated paddy straw
Experiment 1
The object and the plan of this experiment were practically the same as
those of the wheat straw experiment, and the same experimental animals
were used. The ration in the first part of the experiment consisted of un-
treated paddy straw fed ad libitum, a weighed quantity of mustard cake,
one ounce of common salt and, in addition, the animals were receiving 20 gm.
of calcium carbonate per animal per day. This period is designated ' period 3 '.
The object of adding the calcium carbonate supplement was to keep the
animals in calcium balance, since in an earlier trial it had been observed
that the calcium equilibrium could not be maintained without a supple-
ment. In the next period, when alkali-treated paddy straw replaced the
untreated straw (period 4), the calcium carbonate supplement was with-
drawn as the animals were getting enough calcium from the roughage. With
the supplement of calcium carbonate in period 3, the intake of calcium during
both periods 3 and 4 was kept approximately at the same level. The detailed