NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
SULPHUR BALANCE EXPERIMENTS WITH CATTLE AND SHEEP.
211
Further, in our work, we have to differentiate between organic sulphur
and inorganic sulphate. Very frequently, for example in the specimen of hay,
the inorganic sulphate exceeds the organic sulphur. Hence any error
in the total sulphur falls entirely on the organic sulphur which is found by
difference. In the present case, an error of 0.2 mgrm. in the total sulphur deter-
mination of the hay would cause an error of 10 per cent. in the organic sulphur.
Finally we have found like Marston [1928] that the copper nitrate method
is unsafe with many cattle urine samples, which, owing to the high content
of hippuric acid, tend to deflagrate. To overcome these obstacles, in balance
experiments with cattle reported in an earlier paper [Warth 1932], one of us
devised and employed a new process for the determination of sulphur.
Briefly, the procedure consisted in a nitric acid oxidation followed by alkali
fusion, the latter step being essential for the complete oxidation of sulphur, as
will be shown below.
The original process was used in two forms, for urine and for foodstuffs
respectively. These will each be described briefly together with the improvements
we have introduced as the result of our joint further experience.
DETERMINATION OF TOTAL SULPHUR IN URINE.
As the organic sulphur may not be more than a tenth of the total sulphur, in
this determination, the difficulties attending oxidation cannot be minimised by
reducing the amount of material. A sufficient amount to give a determinable
increase of precipitate must be used. The method originally adopted for dealing
with cattle urine was as follows : Some suitable aliquot of urine (about 100 c.c.)
is treated with 10 to 15 c.c. concentrated nitric acid and slowly heated on a sand
bath until a reaction with gentle effervescence commences. The beaker is re-
moved and the action is allowed to proceed to an end without heating. After
reheating, and cooling overnight, nitrophenols and hippuric acid are filtered off
and the liquid concentrated to a small volume, rediluted and concentrated, this
treatment being repeated until dilution does not cause turbidity. After filtra-
tion, the yellow solution is made to 100 c.c. and an aliquot taken for fusion. For
the fusion 5 c.c. of 50 per cent. sodium hydroxide are added, mixed and the whole
transferred to a silver basin. The water is evaporated off, the dry residue is
heated on the sand bath and finally fused. The fusion is completed in a few
minutes resulting in a pure white melt which is dissolved in water, treated with
hydrochloric acid to remove nitric acid, filtered to remove small amounts of
silver chloride and silica and is then ready for precipitation of barium sulphate
in the usual way.
Beyond increasing the sand bath heating preparatory to fusion, we have
not found it necessary to alter this procedure.
2
212
THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY. [V, III
The accompanying table of urinary sulphur determinations made in the course
of our work shows that a considerable quantity of urine must be oxidised to
obtain a determinable amount of organic sulphur.
Excretion of urinary sulphur and sulphate (expressed in grms. barium sulphate
per day).
Volume of urine c.c. .
Total sulphur . . .
Sulphate sulphur . .
Organic sulphur (By differ-
ence).
1
773
2.267
2.088
0.179
Sheep number.
3
776
1.830
1.675
0.155
5
269
4.822
4.382
0.440
7
268
5.267
4.812
0.455
Sheep 1 and 3 received basal ration ; sheep 5 and 7 basal ration plus sulphate
supplement.
DETERMINATION OF TOTAL SULPHUR IN FOOD-STUFFS.
The technique originally employed was as follows : 4 to 5 grms. of dry sub-
stance are exidised with nitric acid in a kjeldahl flask, the reaction being allowed to
proceed in the cold for a time. Heat is then gradually applied, finally boiling
or simmering being continued for several days. By this means sulphur in all
forms is oxidised but a little fat and much cellulose remain intact while the liquid
contains nitrated organic compounds in solution. The digest is diluted, allowed
to stand and is filtered. The filtrate is evaporated nearly to dryness, 10 to 20
c.c. 50 per cent. sodium hydroxide are added and the fusion carried out as in the
case of urine.
It was stated above that after filtering off the intact cellulose the liquid
contains some nitrated organic substance. The subsequent treatment, as outlined
above, is not able to deal very efficiently with this organic matter, hence the
endeavour to carry the oxidation as far as possible by prolonged nitric acid treat-
ment.
The original process, thus outlined, is undoubtedly very tedious; it is also
liable to fail at times when the amount of organic matter remaining in solution
happens to be more than usual. In such cases deflagration ocours during fusion.
We have made the interesting observation that the amount of unoxidised organic
matter in solution is very constant for any one substance and differs considerably
with different substances. As the amount becomes larger, the determination by
SULPHUR BALANCE EXPERIMENTS WITH CATTLE AND SHEEP.
213
this process becomes increasingly difficult. It was found that hay, grass and
fæces could be dealt with easily. Great difficulty was experienced with ground-
nut cake, while with linseed cake the process failed invariably.
Further experiments on this point lead us to believe that the nature of the
nitrogen free extract determines the amount of soluble organic matter. Tests
carried out by us showed that filter paper (cellulose), groundnut oil (fat) and
wool (protein) yield very little soluble organic matter and are easily oxidised
by this process. Hence it can be only the nitrogen free extract that is liable
to yield excessive amounts of resistant nitrated products. It is a very curious
fact, deserving further study, that the nitrogen free extract of coarse fodders
cause less trouble than the nitrogen free extract of some oil cakes.
The original process, as outlined above, has been considerably modified and
improved. The determination is now carried out as follows : 5 to 10 grms. of
substance are oxidised with boiling nitric acid for 6 hours. The contents of the
flask are washed into a beaker, diluted and allowed to stand over-night. The
liquid is filtered off and concentrated in a beaker to reduce the volume to 25 c.c.
when the beaker is covered with a watch glass. The gentle boiling and con-
centration cause further oxidation with production of brown fumes. More acid
is added, if necessary, until no further oxidation can occur by this means. The
liquid is cooled, diluted and, if necessary ; filtered. It is evaporated on the water
bath, 10 c.c. of 50 per cent. sodium hydroxide and 1-2 grms. of potassium nitrate
are added, the whole is transferred to a silver dish, dried and fused.
As an example of what can be effected by this technique, we may quote a
series of sulphur determinations of sheep fæces recently carried out by us.
The question was to determine the effect of a supplement of sodium sulphate
on the amount and nature of the fæcal sulphur. The results are shown in the
accompanying table:—
Distribution of sulphur in faeces as influenced by feeding a sulphate supplement
(All forms of sulphur expressed as grms. sulphur per cent.).
Sheep
No.
1
2
3
4
Average
Ration with supplemenl
Total
sulphur.
0.1421
0.1325
0.1300
0.1359
0.1351
Inorganic
sulphate.
0.0210
0.0174
0.0174
0.0211
0.0192
Organic
sulphur.
0.1211
0.1151
0.1126
0.1148
0.1159
Sheep
No.
5
6
7
8
Average
Basal ration.
Total
sulphur.
0.1110
0.1088
0.1038
0.1062
0.1074
Inorganic
sulphate.
0.0099
0.0128
0.0088
0.0162
0.0119
Organic
sulphur.
0.1011
0.0960
0.0950
0.0900
0.0955
214
THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY. [V, III
No doubt with careful work 1 grm. samples would show a difference in the
sulphur content of the two sets of fæces, but by oxidising 10 grms. we have been
able to measure the difference with a considerable degree of accuracy.
A FURTHER MODIFICATION FOR DEALING WITH 100 GRMS. OF MATERIAL.
In certain experiments owing to sampling difficulties, it became desirable to
deal with quantities of material up to 100 grms. in amount. We have found that
the sulphur can be completely extracted from such material by boiling with
dilute nitric acid. An actual test was carried out thus : 112.65 grms. of Dhub
grass were weighed into a litre beaker, 500 c.c. dilute nitric acid (1:3) were added
and heated to commence a gentle reaction. Removing the source of heat, the
reaction was allowed to proceed, with stirring, to completion. The beaker was
again heated, covered and the contents boiled vigorously for 12 hours, the volume
being maintained by addition of water. The mixture was allowed to stand over-
night filtered on a Büchner funnel and thoroughly washed with distilled water.
The filtrate and washings were made up to 2000 c.c. and an aliquot of
100 c.c. was used for the determination of sulphur by fusion.
The residual organic matter on the Büchner funnel was exhaustively oxidised
by prolonged boiling with concentrated nitric acid. The residue from this treat-
ment was found to consist of silica only.
The nitric acid solution was treated as usual for the total sulphur determina-
tion and yielded 2.5 mgrms. barium sulphate of which 0.5 mgrms. must be deduct-
ed as the reagent blank. The test suggests that the first treatment with dilute
nitric acid failed to dissolve a small residual amount of sulphur equal to 2 mgrms.
barium sulphate. This is not quite correct. We have learnt since, that washing
the residue with distilled water only is not quite effective. Nitric acid water
should be used. However, in spite of this slight imperfection in washing, the result
obtained was as follows :
Per cent. of total sulphur in dhub grass.
As found in the first dilute nitric acid extract
As found after allowing for further yield by concentrated nitric
acid
..........
0.6317
0.6324
All but an insignificant fraction of the total sulphur was recovered in the
first treatment.
NOTE ON THE INCOMPLETENESS OF THE EFFECTED BY NITRIC ACID.
We have carried out a number of duplicate determinations of total sulphur,
in the one case relying upon nitric acid oxidation only, in the other case carrying
out the double process of nitric acid oxidation followed by fusion.
SULPHUR BALANCE EXPERIMENTS WITH CATTLE AND SHEEP.
215
The results of these tests, given in the accompanying table, show that nitric
acid alone fails to give the full value, a subsidiary fusion or other oxidation being
absolutely necessary.
Effect of fusion on the yield of sulphur in different substances.
Substances
Hay
Guinea grass
......
Groundnut cake
.....
Urine
Fæces
.......
Wool
Yield of barium sulphate in mgrms.
Without fusion.
61.5
75.5
101.5
115.5
86.5
93.0
After fusion.
65.0
87.5
104.0
119.0
92.0
95.5
SUMMARY.
A new method is described for the determination of sulphur in vegetable and
animal products.
Briefly, the process consists of nitric acid oxidation followed by alkali fusion.
The process is lengthy, but is recommended as more appropriate than other
standard methods where large amounts of material have to be oxidised.
REFERENCES.
Aiten, H. A. A. (1930). Biochem. Jour. 24 250.
Benedict, S. R. (1909). Jour. Biol. Chem. 6, 363.
Denis, W. (1910). Jour. Biol. Chem. 8, 401.
Evans, R. E. (1931). Jour. Agri. Sci. 21, 806.
—(1933).
Jour. Agri. Sci. 23, 459.
Frear, D. E. (1930). Jour. Biol. Chem. 86, 285.
Hodsman, H. J. (1921). Jour. Chem. Ind. April, 74T.
Marston, H. R. (1928). Com. of Austr. Council of Sci. & Ind. Res. Bull. 38,10.
Methods of Analysis. A O. A. C.(1931). 3rd Edn. p. 109.
Warth, F. J. (1932). Ind. Jour. Vet. Sci. and Anim. Husb. 2, 225.
A FEEDING EXPERIMENT WITH SHEEP.
BY
F. J. WARTH, D.Sc., I.A.S., AND T. S. KRISHNAN, B.A.
Animal Nutrition Section, Bangalore.
(Received for publication on 31st May 1935.)
The rearing and breeding of sheep on modern lines has only recently been
taken up in India, but interest in the subject, especially from the point of view
of wool production, is extending rapidly. There is no doubt that the Nutrition
Section will have to take an important share in this work in studying the nutri-
tional aspects.
The present paper describes the result and experience obtained by us in a
preliminary feeding trial extending over 17 months. The object of the experiment
was to study the food consumption, the digestive capacity and the wool produc-
tion of the local type of sheep. The test was commenced with 6 animals, the
number being increased to 8 later. Mature castrated rams were used. The
feeding was alike for all, the ration consisting of a fixed quantity of groundnut
cake, a fixed amount of green grass and hay ad lib. They were also given a daily
supplement of 2 grms. of calcium phosphate. The daily hay and Guinea grass
consumption of each animal was determined by collecting and weighing the
residue from a known amount supplied.
This feeding test was continued for about 17 months and was divided into 3
approximately equal periods, two digestion trials being carried out during each
period and a clean shearing of wool being made at the end of each period. The
live weight of each animal was recorded daily.
The experimental results are discussed under the following heads :—
1. Digestibility trials.
2. Food consumption.
3. Live weight fluctuations.
4. Wool production.
It should be explained that a series of sulphur balance experiments, report-
ed elsewhere [Warth and Krishnan 1935], was carried out with the same animals
at the same time. For the sulphur balance tests the animals were divided into
two groups, but this grouping does not affect the feeding trial in which the
animals have been treated as a single group.
( 216 )
A FEEDING EXPERIMENT WITH SHEEP.
217
EXPERIMENTAL.
1. Digestibility trials.
Six sets of digestion trials were carried out at somewhat irregular intervals
during the long period feeding test. In the first and second tests six animals were
used, in the later tests 8 animals. However the two new animals were found
to be less efficient, hence they have been excluded from the main discussion which
is based on the results obtained with the six original animals. Table I shows the
average digestion attained in six separate trials, each figure being the average value
obtained with six sheep.
TABLE I.
Group average digestion results.
(Each figure is the average of results from six sheep).
Experiment No.
1
2
5 ....
...
8
10
12 ....
.
Average
Ration.
Total
dry
matter
con-
sumed.
731.5
660.0
686.4
658.4
771.1
761.5
711.5
Percent.
protein
in
ration.
5.70
7.18
7.31
6.88
6.03
5.96
6.51
Per cent.digestion.
Organic
matter.
53.9
51.5
52.6
52.6
53.7
52.0
52.7
Crude
protein.
54.2
59.6
56.2
58.2
57.4
57.4
57.2
There are some remarkable fluctuations in food consumption. In the se-
cond, third and fourth tests the animals consumed less than the normal amount,
while in the last two tests the food consumption was much above the average.
All the animals behaved alike in this respect.
The differences are due partly to variations in the quality of the hay and partly
to the fact that the animals were in better condition and health at the end of the
experiment. The digestibility of total organic matter, which may be taken as
the best single criterion of a ration, is liable to be depressed sometimes when food
B
218
THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY. [V, III
consumption is considerably increased. It is significant that no such depression
is revealed in these figures. On the contrary the highest consumption coincides
with highest digestion and the lowest consumption with lowest digestion. This
would indicate that the quality of fodder varied perceptibly and influenced food
consumption to an appreciable extent.
The variation in the percentage of protein in the ration is due partly to fluc-
tuations in the protein content of the hay and partly to the proportion of hay
in the ration, the greater the amount of hay the smaller the percentage of protein
in the ration.
The digestibility of protein is found to be roughly parallel to the percentage
of protein in the ration, except in the third experiment. There is no obvious
reason for this anomalous result. We can only state the fact that 5 out of the 6
animals failed to come up to the anticipated standard in this test. If there was
a peculiarity in the fodder, it was not noticed by us.
Individual variations are shown in Table II, in which the results of each
animal are compared with the corresponding group averages.
TABAL II.
Individual digestion results compared with group average.
Sheep
No.
1
2
3
5
6
7
Food consumption.
Actual.
769.1
604.0
620.5
827.1
747.6
700.3
Per 100 lbs.
live
weight.
1083
1098
1410
1216
1206
1300
Ration
grms.
+ 57.7
— 107.8
—90.9
+ 115.6
+ 36.1
—11.2
Excess over group average.
ercent.
crude
Protein.
+ 0.22
+ 0.22
+ 0.42
— 0.22
—0.36
—0.12
Percentage digestion.
Organic
matter.
+ 1.8
+ 0.2
+ 0.9
—0.9
—0.2
—1.1
Crude
protein.
+ 1.07
+ 1.95
—0.60
—0.90
+ 0.05
—2.90
Each figure is the mean of six tests with one animal. It may be noted that No.17
sheep consumed least food for its size and attained the best digestion, while No. 7
consumed much food for its size and attained the lowest digestion. Here the
A FEEDING EXPERIMENT WITH SHEEP.
219
disturbing factor of varying food quality has been eliminated (because each figure
represents tests with all the rations), thus enabling the normal effect of ration bulk
to become visible. Allowing for this effect, the digestion attained by all the
animals except No. 3 is very uniform.
No. 3 was anomalous in many ways. It was much smaller than the others,
it differed from the normal in appearance and evidently possessed a larger capa-
city for food.
The two new sheep were tested in four experiments. In every case they gave
decidedly lower digestion results than the corresponding group averages of the
six animals. The results are briefly summarised here.
TABLE III.
Digestion experiments with two new sheep (Nos. 4 and 8).
Experiment No.
5 . . .
8 . . .
10
12 . .
Group average .
Sheep No. 4 . .
Sheep No. 8 . .
Group average
.
Sheep No. 4 .
Sheep No. 8 .
Group average
.
Sheep No. 4
.
.
Sheep No. 8
Group average
.
Sheep No. 4 .
.
Sheep No. 8 .
Average for sheep 4 and 8
Ration.
Total
dry
matter.
686.4
763.3
834.5
658.4
717.2
849.8
771.1
934.0
900.9
761.5
874.5
885.1
851.1
Percent.
crude
protein.
7.31
7.07
6.43
6.88
6.79
6.28
6.03
5.66
5.76
5.96
5.83
5.69
6.19
Percent. digestion
Organic
matter.
52.6
50.8
50.4
52.6
49.7
49.4
53.7
50.6
51.5
52 .0
51.0
48.9
50.3
Crude
pro-
tein.
56.2
50.5
49.8
58.2
52.1
51.1
57.4
52.2
48.4
57.4
50.6
52.3
51.8
B 2
220
THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY. [V, III
There is evidence to show that these digestion results are related, to some ex-
tent to the age of the animals. No. 1 is the youngest (2 years, 10 months). No. 2
comes next (just over 3 years). No. 5 is 3 years 6 months. Nos. 6 and 7 are 4
years old or somewhat over. No. 4 is about the same as 6 and 7. No. 8 is 5
years old.
2. Food consumption.
The daily average food consumption of individuals is shown in Tables IV
and V which give respectively consumption per head and per 100 lbs. live weight.
TABLE IV.
Average food consumption in grms. dry matter per day per head.
Sheep No.
First period . . .
Second period .
Third period . .
1
834
744
761
2
666
612
644
3
654
537
601
4
..
728
838
5
869
757
784
6
734
724
772
7
669
706
749
8
..
809
852
TABLE V.
Average food consumption in grms. dry matter per 100 lbs. live weight.
Sheep No.
First month ..
First period ..
Second period ..
Third period ..
1
1411
1174
1048
1072
2
..
1211
1113
1171
3
1745
1476
1220
1366
4
..
..
921
1061
5
1498
1275
1113
1153
6
..
1184
1168
1245
7
..
1239
1307
1387
8
..
..
1305
1374
It will be observed that generally the highest food consumption
occurred in the first period. There was a decided fall in the second
period and a recovery in the third. However, the consumption during the
first period cannot be considered quite normal. Some of the animals gorged
themselves at the commencement and the unusual consumption during the first
two months made the average for this period somewhat above normal. The
A FEEDING EXPERIMENT WITH SHEEP.
221
tables show that these remarks apply specially to sheep Nos. 1, 3 and 5. That
a consumption of 1400 grms. is unusual may be seen from the normal for 2 good
sheep Nos. 6 and 7. No. 7 in particular has made a very good performance
and its consumption did not average 1400 grms. The initial high consumption
cannot be attributed to the quality of the food either, because Nos. 6 and 7 did
not react to it.
Comparing the capacities of the animals with one another, as shown by the
consumption per 100 lbs. live weight, the figures indicate that Nos. 3, 7 and 8
were the best eaters for their size. Nos. 2, 5 and 6 were intermediate and Nos.1
and 4 were poor. It will be shown below that the performance has not been
in this order at all. The actual composition of the ration consumed is shown in
summary form in Table VI.
TABLE VI.
Average food consumption for entire feeding test.
Sheep
No.
1
2
3
4
5
6
7
8
Grams dry matter per day.
Hay.
604
525
447
640
647
587
555
678
Guinea
grass.
121
70
102
92
101
110
107
100
Ground-
nut
cake.
55
45
46
55
55
46
46
55
Total.
780
640
595
787
803
743
708
833
lbs.
Starch
equiva-
lent.
0.555
0.452
0.330
0.556
0.567
0.520
0 499
0.585
Food consumption
per 100 lbs.
live weight.
Dry
matter
grms.
1100
1165
1350
999
1181
1198
1311
1343
Starch
equi-
valent
lbs.
0.78
0.82
0.97
0.70
0.83
0.84
0.92
0.94
3. Live weight fluctuations.
The accompanying summary, Table VII, shows the live weight changes which
occurred during each period.
222
THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY. [V, III
TABLE VII.
Live weight fluctuations.
First period.
First Period.
Initial weight, lbs. .
Final weight, lbs. .
Gain, lbs . . .
Shearing effect . .
Second Period.
Initial weight, lbs. .
Final weight, lbs. .
Gain, lbs.
.
Shearing effect, lbs.
Third Period.
Initial weight, lbs.
Final weight, lbs.
Gain, lbs..
Shearing effect, lbs.
Live weight increase for
entire test.
Live weight increase for
100 days.
Sheep No.
1
67
73
6
—5
68
70
2
0
70
75
5
—4
8
1.40
2
52
58
6
—5
54
55
1
— 1
54
57
3
—2
5
1.00
3
47
45
—2
—3
42
45
3
—1
44
47
—3
—3
0
0.00
4
..
..
..
..
81
78
—3
—2
76
79
3
—2
—2
—0.62
5
63
70
7
—4
66
69
3
—2
67
70
3
—4
7
1.40
6
55
63
8
—3
60
63
3
— 2
61
65
4
—1
10
2.00
7
47
54
7
—3
51
58
7
— 2
56
59
3
—3
12
2.40
8
..
..
..
..
62
61
—1
—1
60
62
2
—1
0
0.00
A FEEDING EXPERIMENT WITH SHEEP.
223
TABLE VIII.
Live weight fluctutions.
(Live weight excess at end of each period over initial
live weight in lbs.).
Initial .
End of first period . . .
End of second period . .
End of third period
.
Sheep No.
1
Live
Wt.
67
73
70
74
Ex.
...
6
3
7
2
Live
Wt.
52
58
55
57
Ex.
...
6
3
5
3
Live
Wt.
47
45
45
47
Ex.
...
—2
—2
0
4
Live
wt.
...
81
78
79
Ex.
...
...
—3
—2
5
Live
wt.
63
70
69
70
Ex.
...
7
6
7
6
Live
Wt.
55
63
63
65
Ex.
...
8
8
10
7
Live
Wt.
47
54
58
59
Ex.
...
7
11
12
8
Live
Wt-
...
62
61
62
Ex.
...
...
—1
...