NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
264 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [I, IV.
formed where a dry product was aimed at. The loss of dry matter in this pit was
found to be 4.85 per cent. and 6.94 per cent. respectively on the corrected and
uncorrected basis (Table VII). This is the lowest loss recorded in any of the pits.
It seems probable that the actual loss was very much greater, but has been
replaced to a considerable extent by material washed down from the spoilt surface
layer where extensive decomposition took place. Further evidence in support of
this view will be brought forward below (see nitrogen losses). In spite of this
large replacement the organic matter loss comes to 10.0 per cent. (Table XV),
which is indeed a high figure, even as it is. The figures of this pit are of interest
in showing what may occur in a flooded pit.
Considering the evidence of the unspoilt pits, it may be said that rapid
filling causes a larger loss of dry matter than slow filling, while watering gives a
better aroma and consistency to the resulting product. So, to obtain the best
results, it is indicated that filling should be done reasonably slowly, and water
should be added in sufficient amount to avoid the production of a very dry silage
and to improve the aroma.
The average loss of the dry matter in this experiment works out to 7.67 per
cent. if all the bags in all the pits are considered. This experiment shows a higher
loss than the last one (l. c.) which gave a loss of only 4.2 per cent. for dry matter.
The loss of 7.67 per cent. noted here agrees remarkably well with the loss of
7.7 per cent. noted by Amos and Woodman (Journal of Agricultural Science, XV,
344) at Cambridge in the production of "Acid Brown" silage, though working
with different material, as well as with the loss of 7.5 per cent. noted by Annett
and Aiyer (Memoirs of the Department of Agriculture in India, Chemical Series,
Volume VIII, No. 10), also working with Jowar.
In this connection it is very important to remember that there are two types
of losses in the process of the preparation and utilisation of silage. The first is the
loss resulting from the activity of enzymes, bacteria, etc., which cause the fermen-
tation, and produce the typical characteristics of silage. It is this loss that has
been studied in these experiments and it is only this loss that has been recorded.
The second kind of loss is due to the production of mouldy, rotten silage at the
sides and top of the silo. This, of course, cannot be avoided entirely, but could
be reduced to a minimum by suitable means. It is under this latter category that
the rapidly filled pits, and more especially pit No. 4, show considerably larger
losses than the others (Table III). In pit No. 4, as has already been noted, the
thick layer of rotten silage at the top formed a very large proportion, about a third,
of the total. In this respect also, therefore, the slowly filled pits score an
advantage over the rapidly filled ones.
SILAGE INVESTIGATIONS AT BANGALORE 265
The percentage composition of the samples ensiled, as well as of the silage pro-
duced, is given in Tables VIII to XI. The changes affecting the entire contents of
the experimental bags in all the various constituents may be gathered from Tables
XII to XV.
B. Changes in the Nitrogenous Constituents.
That considerable changes take place in the proteins of plants during ensilage
is too well known to be emphasised. Not only is the quantity of protein liable
to be changed, but also the quality, to a very large extent. Whereas a loss of
8.4 per cent. of the crude protein was noticed in the previous experiment, in the
present case there are wide variations. No. 1 pit shows an average loss of 5 per
cent., No. 2 an average gain of 2.2 per cent. and No. 3 pit, an average loss of less
than 1 per cent. Pit No. 4 shows an increase of 13.3 per cent. There is little
doubt that this exceptional result is due to leaching down of soluble nitrogenous
material from the surface mass of organic matter destroyed. It may be noted that
a similar explanation was offered for the apparently small loss of dry matter in
this pit.
An uniformly large decomposition of true protein takes place on ensilage. The
losses of true protein are very considerable, and taking the reasonable view that
the most easily available portion of it — which must evidently be the most valu-
able — is the quota lost, it is clear that the resultant protein must certainly be
far less digestible than the protein of the green plant. Such has also been the
experience, without a single exception, of the Nutrition Section at Bangalore, with
silage rations.
The percentage losses of true protein on ensilage are fairly uniform (Tables
XII to XV), except in bag No. 19 where there was a slight increase of 2.2 per cent.
A comparison of the figures for the different pits shows that watering, as well as
rapid filling, tend to increase the loss of this constituent. The average loss for all
the pits works out to 29.0 per cent. which is slightly more than that noted in the
previous experiment.
A better idea of the extent of the decomposition of true protein on ensilage is
given by a study of Table XVI, which gives the percentage ratio of true to crude
protein before and after ensilage. The average for the four pits shows that the
proportion is reduced from 72.46 per cent. to 50.06 per cent. on ensilage. The loss
of true protein is seen in the increase of " Amides " (Tables XII to XV). The
average increase of this constituent, for all pits, is 81.4 per cent. The increase in
" Amides " is proportional to the loss of true protein.
The changes in the nature and extent of the important decomposition products
of protein, viz., amino acids and volatile bases, as well as of asparagin, is given in
266 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [I, IV.
Table XVII. It will be seen therefrom that volatile bases and amino acids
increase on ensilage, while asparagin diminishes. While the production of volatile
bases is not much affected by the alteration in the conditions of ensilage, it is
quite significant, that, in the unwatered pits, the amino acids show a considerable
diminution in two bags, is not much affected in another, and one shows an increase.
It is also the amino acids which bring out clearly the effects of leaching, especially
in the watered pits, by the draining down of the expressed juice, e.g., No. 7 bag
which was at the top shows a loss, while No. 5 at the bottom records a large gain.
Similarly, No. 17, an upper bag, shows a much smaller increase than No. 15, the
corresponding lower one.
It is also noteworthy that there was a greater production of amino acids in this
experiment than in the last one and hence the ratio of volatile bases to amino acids
(Table XVIII) is lower than the figures of the older experiment. The increase in
volatile bases over amino acids produced, confirms the previous work in India,
that good silage can result in spite of a higher production of the former over the
latter. The ratio is consistently less than unity and the average of 0.62 could be
given as supporting the observation of the Cambridge workers, that in good silage
the ratio is small.
C. Changes in the Ether Extract.
The most important component of the plant which is primarily affected by
bacterial action during ensilage is the carbohydrate fraction, which is converted
into organic acids, carbon-di-oxide and water. The organic acids are all soluble in
ether and hence they are included in the term ether extract. The increase under
this head in a measure of organic acid production, and hence, indirectly, of bacte-
rial activity in the silos. There is always a very considerable increase in the ether
extract as the result of ensilage. An average increase of 103.8 per cent., for the
four pits, has been recorded. The individual figures may be seen from Tables XII
to XV. In all cases the bottom bags show a greater increase than the top ones.
This is probably due to the leaching action of the expressed juice which washes
down the soluble constituents as it descends, thus depleting the upper layers and
enriching the lower strata.
Table XIX gives in detail the changes in the volatile as well as non-volatile
organic acids as the result of ensilage. It will be seen therefrom that very large in-
creases take place in both constituents. Another significant fact revealed therein
is the considerably larger production of volatile organic acids in the watered pits.
The same remark holds good for the non-volatile acids as well. It is also noticeable
that rapidity of filling has a similar influence in increasing the organic acid pro-
duction, though to a smaller extent than watering.
SILAGE INVESTIGATIONS AT BANGALORE
267
It is very remarkable that in the present experiment it has been observed that
all the organic acids present in the green plant are entirely volatile, only three bags
showing the presence of non-volatile acids as well. On ensilage, however, enor-
mous quantities of non-volatile acids are produced in all bags. This distribution
of organic acids in the green plant is not in agreement with the former observa-
tions. There, a large amount of non-volatile organic acids which was present
before ensilage was lost during ensilage.
Essentially, it is the nature and extent of the organic acids produced that de-
termines the quality of silage which results. It has been stated by the Cambridge
workers that a greater production of non-volatile acids than volatile ones is essen-
tial for the silage to be of good quality. This has been found to be quite unneces-
sary by all workers in India and this experiment is a further confirmation of the
same. Table XX shows that, except in two cases, the ratio is greater than unity ;
nevertheless the resultant silage has been of excellent quality. What seems to be
the deciding factor is the nature of the volatile acids produced. The absence of
butyric acid is essential for the silage to be good. In the experiments conducted
here no butyric acid, at least not sufficient to be identified, was observed.
D. Changes in the Carbohydrates.
Over 80 per cent. of the dry matter of plants consists of carbohydrates. It is
at their cost that the main bacterial activity goes on during ensilage and hence
they suffer the largest losses. The changes in this group of substances could be
more easily dealt with under the following three heads :—
(1) Changes in the Nitrogen free Extractives.—Evidently the soluble carbohy-
drates would be the first to suffer loss due to bacterial action, as they
are the most easily attacked. As has already been stated, the end
products of bacterial action on this group of substances are organic
acids, CO 2 and H 2 O. The first has already been considered, the second
escapes and the last is absorbed by the silage. The loss of N-free ex-
tractives as seen from Tables XII to XV is 14.4 per cent., 12.0 per
cent., 31.1 per cent. and 20.3 per cent., respectively, in pits 1 to 4.
Evidently rapid filling accounts for the greater losses in pits 3 and 4.
This is probably due to the large bulk of enclosed air, resulting from
insufficient packing, stimulating destructive bacterial and other
changes. Watering also increases the loss, though to a smaller
extent.
(2) Changes in Crude Fibre.—Crude fibre is always broken down to vary-
ing extents during ensilage. The losses noted here are not very high,
268 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ I, IV.
but are more than that noticed in the earlier experiment. The
average loss for the 4 pits is 8.15 per cent., the individual figures being
4.2 per cent., 7.8 per cent., 12.7 per cent. and 7.9 per cent. respective-
ly in the various pits in serial order. Rapid filling has caused the
largest loss (Pit 3). Watering also seems to have inhibited this loss
to some extent as is seen from the lower loss in No. 1 than in No. 2.
Hence the loss in No. 3 would have been more serious if no watering
had been done.
(3) Changes in the Total Carbohydrates.—The losses of total carbohydrates
(i.e., nitrogen free extractives+crude fibre) were found to be 10.4 per
cent., 10.3 per cent., 24.1 per cent. and 15.3 per cent. respectively, in
pits 1 to 4. The losses are fairly uniform, and as has already been
pointed out, there is an increased loss due to rapid filling.
E. Changes in the Inorganic Constituents.
The changes in ash (Tables XII to XV) are very important. While No. 1 pit
shows a loss of 13.3 per cent., No. 2 denotes a loss of only 2.9 per cent., the former
must evidently be due to the enhanced leaching action of the added water. It
seems, apparently, surprising that pits 3 and 4 should show gains. But the
reason is not far to seek. It must be due to the self same leaching action on the
large amount of decomposing surface material. This seems to be the only possible
explanation for the remarkably large gains of 25.6 per cent. and 13.2 per cent.
respectively (Table XV) in the bags in pit 4. In pit 3 the upper bag shows a gain
of 0.9 per cent. while the lower one has gained to the extent of 20.1 per cent. It
may be noted that watering and rapid filling have acted as a fillip to the leaching
action of the drainage juice. Thus while the lower bags in the slowly filled pits
show gains of 0.0 per cent. and 1.9 per cent. only, the corresponding upper ones
show losses of 26.6 per cent. and 7.8 per cent. respectively. The higher loss has
taken place in the watered pit.
It is rather interesting that variations in silica are not insignificant when com-
pared to the soluble ash. The above figures, for the total ash variations due to
leaching, are also repeated for the soluble ash and silica. The movement of silica
down the pit emphasises, more than ever, the washing down of various constituents
by the expressed juice which travels down the silo. This considerable movement
of silica has also been observed in other experiments at Bangalore. This point is
of considerable practical significance in that a very great increase of insoluble ash
must always be expected in the lowest layers of silage.
A detailed analysis of the components of the soluble ash and the changes
undergone by them as the result of ensilage is given in Tables XXI to XXIV. As
SILAGE INVESTIGATIONS AT BANGALORE
269
is but natural the constituents show less loss in the lower bags than in the upper
ones. SO 3 alone is rather peculiar. Considerable losses are noticed in the slowly
filled pits, while large gains are evident in the rapidly filled ones, probably due
to reasons already adduced above. However, it has to be remembered that only
sulphate sulphur was determined and most if not all of the organic sulphur might
have escaped, undetermined. It has also to be pointed out, that, while in the last
experiment, under conditions of filling similar to those of pit 1, a gain of SO 3 was
noticed, the present experiment reveals a loss on ensilage.
Barring pit 4, which shows a gain in all items owing to the cause already set
out, all the others show losses of varying degree in P 2 O 5 , CaO and MgO. They all
show gain in the alkalis owing to the leaching action. These being the most soluble
components would be the first to be affected. This is also evident from the fact
that the upper bags show losses in the case of pits 1 and 2, while the lower ones
show large gains. Pit 3, owing to the fact that greater leaching has taken place
even from the very top, shows a gain in both bags, though it is less in the upper
than in the lower one.
SUMMARY.
The effect of varying the conditions of ensilage on the resultant product was
studied. There was little difference in the quality of the silage produced though
conditions of filling varied considerably. " Acid Brown " silage of good quality,
with slight variations in acidity in the different pits, was produced.
The maximum temperature recorded varied between 36°C and 47.8°C.
The losses of dry matter and organic matter noticed, agree with the results of
Amos and Woodman and Annett and Aiyer.
Changes in the proteins, ether extract, carbohydrates and minerals were
studied.
It has been noticed that extensive decomposition of true protein takes place
with a large increase of "Amides ", owing to the production of considerable quan-
tities of volatile bases and amino acids. The ratio of the former to the latter
was less than unity, thus confirming the work of the English workers. The large
increase in volatile bases, along with the production of good silage, also supports
the work in India.
Very large quantities of organic acids, both volatile and non-volatile, have been
developed as the result of ensilage. The ratio of the former to the latter is greater
than unity, thereby supporting the past observations in India.
Carbohydrate losses, both as nitrogen free extractives and as crude fibre,
show higher figures than the last experiment at Bangalore but agree fairly well
with those of Amos and Woodman.
270 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ I, IV.
It has been noticed consistently, in all soluble substances, that there has been
a washing down of the same from the top of the pit down to the bottom. This is
best seen in the soluble minerals, especially the alkali salts. Even silica, an in
soluble substance, exhibits this downward movement.
It has been established that slow filling with watering results in the production
of good silage with the least losses in the various constituents.
Acknowledgment.—I wish to acknowledge most gratefully the valuable advice
and helpful criticism given by Mr. F. J. Warth, the Physiological Chemist, during
the preparation of this paper as well as in the carrying out of the experiment.
My thanks are also due to Mr. P. A. Seshan, B.A., for help rendered on various
occasions during the course of this work.
TABLE I.
Details of the filling of pits, disposal of bags and weather conditions.
—
Conditions of filling .
Dates of filling.
Nos. of bags put in at 3'
from bottom.
Nos. of bags put in at 6'
from bottom.
Nos. of bags containing
thermometers.
Weather during filling
Pit 1
Slow filling with
watering.
Commenced on
5th November
102?, continued
on 9th Novem
ber and closed
on 12th Novem
ber 1928, (⅓ fill
ed daily).
13 and 14.
17 and 18.
13 and 17.
Fine on 5th and
9th. Rainy on
11th and 12th.
Pit 2
Slow filling with
out watering.
Commenced on
6th November
1928, continued
on 10th Novem
ber and closed
on 13th Novem
ber 1928. (⅓ fill
ed daily).
16 and 16.
19 and 20.
15 and 19.
Fine on 6th and
10th but rainy
on 11th and
12th,
and
cloudy on 13th.
Pit 3
Rapid filling with
watering.
Completely filled
on 7th Novem
ber 1928.
5 and 6.
7 and 8.
5 and 7.
Fine.
Pit 4
Rapid
filling
without water
ing.
Completely filled
on 8th Novem
ber 1928.
9 and 10.
11 and 12.
9 and 11.
Fine.
SILAGE INVESTIGATION AT BANGALORE
271
TABLE IV.
Pit No. 1.—Dry matter changes in prime Jowar silage. Slow filling with watering.
Bag
No.
13
14
17
18
Weight
of
green
Jowar
Kg.
14.750
15.910
16.930
16.180
Weight
of
silage
Kg.
21.385
23.160
17.165
17.155
Per cent.
dry matter
in green
Jowar
Cor.*
35.89
35.89
27.67
27.67
Uncor.†
35.23
35.23
27.29
27.29
Per cent.
dry matter
in silage
Cor.
23.17
23.59
25.57
24.59
Uncor.
21.46
21.88
24.32
23.34
Total dry mat-
ter in green
Jowar
Kg.
Cor.
5.294
5.710
4.685
4.477
Uncor.
5.196
5.605
4.620
4.416
Total dry mat-
ter in silage
Kg.
Cor.
4.955
5.464
4.389
4.218
Uncor.
4.589
5.067
4.174
4.004
Loss of dry
matter
per cent.
Cor.
6.40
4.31
6.32
5.79
Uncor.
10.68
9.60
9.65
9.33
Average loss
per cent.
Cor.
}5.71
Uncor.
10.07{
Date of
en-
silage
9-11-28
9-11-28
12-11-28
12-11-28
Date of
removal
4-5-29
17-5-29
22-4-29
19-4-29
* Corrected for the loss of volatile bases and volatile organic acids taking place on drying.
† No correction made for the above losses.
272 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ I, IV.
TABLE V.
Pit No. 2.—Dry matter changes in prime Jowar silage. Slow filling without watering.
Bag
No.
15
16
19
20
Weight
of
green
Jowar
ensiled
Kg.
16.995
17.145
17.410
18.040
Weight
of
silage
re-
covered
Kg.
17.343
17.815
16.105
17.860
Per cent. dry
matter in green
Jowar
Cor.*
33.98
33.98
31.51
31.51
Uncor.†
33.37
33.37
31.14
31.14
Per cent. dry
matter in
silage
Cor.
31.82
33.05
30.68
30.19
Uncor.
30.46
31.69
29.86
29.37
Total dry
matter in green
Jowar Kg.
Cor.
5.775
5.826
5.486
5.685
Uncor.
5.671
5.721
5.422
5.618
Total dry
matter in silage
Kg.
Cor.
5.519
5.888
4.941
5.392
Uncor.
5.283
5.646
4.809
5.245
Loss of dry
matter
per cent.
Cor.
4.43
—1.06‡
9.94
5.15
Uncor.
6.84
1.31 ‡
11.31
6.64
Average
loss
per cent.
Cor.
}6.51
Uncor.
8.26 {
Date
of
ensilage
10-11-28
10-11-28
13-11-28
13-11-28
Date
of
re-
moval
27-6-29
19-6-29
20-6-29
10-6-29
* Corrected for the loss of volatile bases and volatile organic acids taking place on drying.
† Not corrected for the above losses.
‡ Owing to some mistake this bag shows a gain in weight and hence this figure has been rejected in taking the average loss.
SILAGE INVESTIGATIONS AT BANGALORE
273
TABLE VI.
Pit No. 3.—Dry matter changes in prime Jowar silage. Rapid filling with watering.
Bag
No.
5
6
7
8
Weight
of
green
Jowar
Kg.
20.045
18.780
17.926
19.015
Weight
of
silage
Kg.
25.730
22.285
22.945
..
Per cent.
dry matter
in green
Jowar
Cor.*
36.38
36.38
37.73
37.73
Uncor.†
35.72
35.72
37.29
37.29
Per cent.
dry matter
in silage
Cor.
24.24
27.12
25.12
..
Uncor.
22.14
25.02
23.63
..
Total dry mat-
ter in green
Jowar
Kg.
Cor.
7.292
6.832
6.763
7.174
Uncor.
7.160
6.708
6.684
7.091
Total dry mat-
ter in silage
Kg.
Cor.
6.237
6.044
5.764
Bag
Uncor.
5.697
5.576
5.422
lost.
Loss of dry
matter per
cent.
Cor.
14.47
11.53
14.77
..
Uncor.
20.43
16.88 }
18.88
..
Average loss
per cent.
Cor.
13.59
..
..
Uncor.
18.73
..
..
Date
of
ensilage
7-11-28
7-11-28
7-11-28
..
Date of
removal
7-11-29
6-11-29
6-11-29
..
* Corrected for loss of volatile bases and volatile organic acids taking place on drying.
† Not corrected for the above losses.
274 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ I, IV.
TABLE VII.
Pit No. 4.—Dry matter changes in prime Jowar silage. Rapid filling without watering.
Bag
No.
9
10
11
12
Weight
of
green
Jowar
Kg.
17.150
16.980
16.630
15.345
Weight
of
silage
Kg.
22.975
21.710
22.240
10.260
Per cent.
dry matter
in green
Jowar
Cor.*
34.49
34.49
37.31
37.31
Uncor. †
33.49
33.49
36.44
36.44
Per cent.
dry matter
in silage
Cor.
23.98
26.25
25.33
29.54
Uncor.
22.68
24.95
24.15
28.36
Total dry mat-
ter in green
Jowar
Kg.
Cor.
5.915
5.856
6.205
5.725
Uncor.
5.744
5.687
6.060
5.592
Total dry
matter in silage
Kg.
Cor.
5.509
5.699
5.633
5.689
Uncor.
5.210
5.417
5.371
5.462
Loss of dry
matter per
cent.
Cor.
6.86
2.68
9.22
0.63
Uncor.
9.30
4.75 }
11.37
2.33
Average loss
per cent.
Cor.
4.85
Uncor.
6.94 {
Date
of
ensilage
8-11-28
8-11-28
8-11-28
8-11-28
Date
of
removal
11-11-29
11-11-29
11-11-29
10-11-29
* Corrected for loss of volatile bases and volatile organic acids taking place on drying.
† Not corrected for the above losses.
SILAGE INVESTIGATIONS AT BANGALORE
275
TABLE VIII.
Pit No. 1.—Percentage composition of prime Jowar—Before and after ensilage—
on dry basis. Slow filling with watering.
Constituents
*Crude protein
....
*Ether extract
....
Nitrogen free extractives . .
Crude fibre
Ash
Silica
.....
True protein
....
Amides
Bag 13
Green Jowar
7.96
1.39
50.92
33.19
6.54
2.49
6.31
1.65
Silage
6.79
2.50
47.50
35.81
7.40
3.21
4.06
2.73
Bag 17
Green Jowar
5.71
1.68
49.03
32.24
11.34
7.23
4.46
1.25
Silage
5.51
1.94
49.00
34.34
9.21
4.88
4.05
1.46
* Uncorrected.
TABLE IX.
Pit No. 2.—Percentage of composition of prime Jowar—Before and after ensilage—
on dry basis. Slow filling without watering.
Constituents
*Crude protein
....
*Ether extract
....
Nitrogen free extractives
Crude fibre
Ash
Silica
.....
True protein
....
Amides
Bag 15
Green Jowar
6.28
1.06
50.35
36.40
5.91
2.03
4.97
1.31
Silage
5.96
2.28
47.88
37.41
6.47
2.18
3.04
2.92
Bag 19
Green Jowar
6.40
1.75
51.66
33 08
7.11
3.13
4.41
1.99
Silage
6.94
1.51
51.10
33.06
7.39
2.94
5.09
1.85
* Uncorrected.
C