NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
June 1948.]
D. G. PANDITTESEKERE, S. C. RAY AND N. D. KEHAR 95
TABLE V
Digestibility co-efficient of maize-oil cakes
—
Consumed from—
Wheat-bhoosa
.
.
.
.
.
.
Maize cake
.
.
.
.
.
.
Total .
Voided in faeces
.
.
.
.
.
.
Total Digested
Digested from—
Wheat-bhoosa
.
.
.
.
.
.
Maize cake
.
.
.
.
.
.
Digestibility co-efficient of maize cake
.
.
Consumed from—
Wheat-bhoosa
.
.
.
.
.
.
Maize cake
.
.
.
.
.
.
Total .
Voided in faeces
.
.
.
.
.
.
Total digested .
Digested from—
Wheat-bhoosa
.
.
.
.
.
.
Maize cake
.
.
.
.
.
.
Digestibility co-efficient of maize cake . .
Consumed from—
Wheat-bhoosa
.
.
.
.
.
.
Maize cake
.
.
.
.
.
.
Total .
Voided in faeces
.
.
.
.
.
.
Total digested .
Digested from—
Wheat-bhoosa
.
.
.
.
.
.
Maize cake
.
.
.
.
.
.
Digestibility co-efficient of maize cake . .
Crude
protein
gm.
Ether
extract
gm.
Crude
fibre
gm.
N-free
extract
gm.
Total carbo¬
hydrates
gm.
Bullock No.1
63.94
122.43
186.37
81.34
105.03
nil
105.03
86
15.36
77.45
92.81
31.43
61.38
5.16
56.22
73
733.95
51.07
785.02
312.16
472.86
447.70
25.16
49
931.29
248.41
1179.70
519.22
660.48
493.58
166.90
67
1665.24
299.48
1964.72
831.38
1133.34
941.28
192.06
64
Bullock No. 2
77.12
122.43
199.55
100.84
98.71
nil
98.71
81
18.56
77.45
96.01
27.87
68.16
6.61
61.55
80
886.28
51.07
937.89
373.18
564.71
541.00
23.71
46
1125.30
248.41
1373.71
613.80
759.91
596.38
163.53
65
2012.12
299.48
2311.60
986.98
1324.62
1137.38
187.24
63
Bullock No. 3
74.36
122.43
196.79
90.47
106.32
nil
106.32
87
17.87
77.45
95.32
25.19
70.13
6.43
63.70
82
853.50
51.07
904.57
359.62
544.95
520.64
24.31
48
1083.00
248.41
1331.41
602.13
729.28
573.99
155.29
63
1936.50
299.48
2235.98
961.75
1274.23
1094.63
179.60
96
Nutritive Value of Maize Oil Cake
[Vol. XVIII, Part II,
TABLE V—contd.
Digestibility co-efficient of maize-oil cakes—contd.
—
Consumed from—
Wheat-bhoosa
.
.
.
.
.
.
.
Maize cake
.
.
.
.
.
.
.
Total .
Voided in faeces
.
.
.
.
.
.
.
Total digested .
Digested from—
Wheat-bhosa
.
.
.
.
.
.
.
Maize cake
.
.
.
.
.
.
.
Digestibility co-efficient of maize cake . .
Average digestibility co-efficient of mazie cake .
Crude
protein
gm.
Ether
extract
gm.
Crude
fibre
gm.
N-free
extract
gm.
Total carbo¬
hydrate
gm.
Bullock No. 4
74.61
122.43
197.04
98.01
99.03
nil
99.03
81
84
17.93
77.45
95.38
25.65
69.73
6.45
63.28
81
79
856.40
51.07
907.47
361.35
546.12
522.40
23.72
46
47
1086.60
248.41
1335.01
620.00
715.01
575.92
139.09
56
63
1943.00
299.48
2242.48
981.35
1261.13
1098.32
162.81
54
60
For comparison, the composition, digestibility co-efficients, digestible nutrients per 100 lb. on
dry basis, total digestible nutrients, nutritive ratio and starch equivalent of maize and other oil-
cakes are given in Tables VI and VII. The data indicate that the digestibility co-efficients of crude
protein in maize cake are similar to those of linseed and rape cakes and slightly lower than of the
other cakes in the list. Compared to that of other cakes, the digestibility of ether extract of maize
is significantly low, though the oil content in the cake is the highest. This is due to the high level
of ingestion of this constituent through the cake. Total carbohydrate digestibility of maize cake
is lower than that of cocoanut cake but compares favourably with those of others.
TABLE VI
Percentage composition and digestibility co-efficients
Cake
Maize oil cake
.
.
.
.
Cocoanut cake (country mill pressed)
Cocoanut cake (expeller) . .
Linseed cake
.
.
.
.
Rape cake
.
.
.
.
.
Til cake
.
.
.
.
.
Groundnut cake
.
.
.
.
Percentage composition
Crude
protein
23.67
23.45
25.34
30.51
36.37
46.30
51.75
Ether
extract
14.97
13.00
8.20
6.57
13.41
9.91
8.22
Total carbo-
hydrates
57.91
55.19
58.12
52.72
40.89
32.77
34.33
Crude
portein
84
90
90
85
85
92
90
Digestibility co-effiicents
Ether
extract
79
100
100
96
93
88
97
Total carbo-
hydrates
60
72
76
60
68
71
43
June 1948.]
D. G. PANDITTESEKERE, S. C. RAY AND N. D. KEHAR 97
TABLE VII
Digestible nutrients (lb.) per 100 lb. of dry and of raw material
—
Maize oil cake . .
Cocoanut cake (country
mill pressed)
Cocoanut cake (expeller)
Linseed cake . . .
Rape cake . . .
Til cake . . .
Groundnut cake . .
Dry material
Crude
protein
19.88
21.10
22.81
25.86
30.92
42.60
46.39
Carbo-
hydrates
34.90
39.75
42.12
31.69
27.76
23.36
14.59
Ether
extract
11.83
13.00
8.20
6.33
12.48
9.32
7.97
Total
81.39
90.10
83.81
71.79
86.77
86.92
78.92
Nutritive
ratio
3.1
3.3
2.7
1.8
1.8
1.0
0.7
Raw material
Digestible
crude
protein
18.10
18.99
20.53
23.27
27.83
38.34
41.75
Starch
equivalent
67.4
76.3
69.1
60.6
75.7
75.9
67.4
Total
digestible
nutrients
74.1
81.1
75.4
64.6
78.1
78.2
71.0
It is seen from Table VI that the digestible crude protein content of maize-oil cake is lowest
among the cakes taken for comparison. The total digestible nutrients and starch equivalent are
similar to those of linseed-cake but significantly lower than of other cakes. In comparison to others,
except cocoanut cake (country mill pressed), the nutritive ratio of maize cake is fairly wide for a
concentrate.
In Table VIII are given the nitrogen, calcium and phosphorus balances determined during the
digestibility trial. The above data show that when maize-oil cake was fed at a level approximately
supplying 100 gm. of digestible crude protein per 100 lb. of body weight, with a common roughage
like wheat-bhoosa, there was significant retention of nitrogen, calcium and phosphorus in adult
animals kept under maintenance conditions.
TABLE VIII
Balances of nitrogen calcium and phosphorus
Hill bull
1 . . . . . . . . .
2 . . . . . . . . .
3 . . . . . . . . .
4 . . . . . . . . .
Average . . . . . . . . .
Intake
29.81
31.94
31.48
31.52
31.19
Out put
Faeces
Urine
Nitrogen balance
13.01
16.13
14.46
15.68
14.82
9.08
9.56
9.08
8.04
8.94
Total
22.09
25.69
23.54
23.72
23.76
Balance
+ 7.72
+ 6.25
+ 7.94
+ 7.80
+ 7.43
G
98
Nutritive Value of Maize Oil Cake
[Vol. XVIII, Part II,
TABLE VIII—contd.
Balances of nitrogen calcium and phosphorus—contd.
Hill bull
1
.
.
.
.
.
.
.
.
.
2
.
.
.
.
.
.
.
.
.
3
.
.
.
.
.
.
.
.
.
4
.
.
.
.
.
.
.
.
.
Average
.
.
.
.
.
.
.
.
.
1
.
.
.
.
.
.
.
.
.
2
.
.
.
.
.
.
.
.
.
3
.
.
.
.
.
.
.
.
.
4
.
.
.
.
.
.
.
.
.
Average
.
.
.
.
.
.
.
.
.
Intake
10.44
12.37
11.95
11.98
11.68
4.79
5.23
5.13
5.14
5.07
Out put
Faeces
Urine
Calcium balance
6.86
8.53
8.60
7.53
7.88
0.96
0.84
0.80
0.90
0.87
Phosphorus balance
3.84
4.41
3.91
4.36
4.13
0.05
0.04
0.05
0.05
0.05
Total
7.82
9.37
9.40
8.43
8.75
3.89
4.45
3.96
4.41
4.18
Balance
+2.62
+ 3.00
+ 2.55
+ 3.55
+ 2.93
+ 0.90
+ 0.78
+ 1.17
+ 0.73
+ 0.89
SUMMARY
In its organic constituents maize-oil cake is similar to cocoanut oil cake, while in inorganic make-
up it is poor and resembles groundnut-cake. The results of the digestibility trial show that the
digestibility co-efficients of maize-cake are, crude protein 84, ether extract 79, crude fibre 47, nitrogen-
free extract 63, and total carbohydrates 60. Compared to that of the commonly used cakes the
digestible crude protein is rather low. Under the feeding conditions of the present experiment using
maize-cake and wheat-bhoosa , nitrogen, calcium and phosphorus balances were significantly positive.
REFERENCES
Halnan, E. T. and Garner, F. H. (1944). The Principles and practice of feeding farm animals. 2nd edition. Longman, Green
& Co., London
Morrison, F.B. (1937). ' Feeds and feeding'. 20th edition. The Morrison Publishing Company, Ithaca, New York
Patel H. D., Patel, B. M. and Dave, C. N. (1944). Indian J. Vet. Sci. 14, 97
Pandittesekere, D. G., Ray, S. C. and Kehar, N. D. Utilization of by-products of starch manufacture from maize as
cattle feeds. I. The nutritive value of maize, husk. Indian J. Vet. Sci. 18, 81
Sen, K.C. (1946). The nutritive value of Indian Cattle foods and the feeding of animals. Misc. Bull. Imp. Coun. Agric.
Res. 25, Manager of Publications, Delhi
102
New Method of Estimation of Oxalic Acid
[Vol. XVIII, Part II,
TABLE I
Metathesis of sodium carbonate and calcium oxalate monohydrate
Observations
1
2
3
4
5
6
7
8
9
10
Calcium
oxalate
taken
(gm.)
0.2085
0.1740
0.0760
0.1400
0.1011
0.0770
0.0774
0.1000
0.1215
0.0770
Time of boiling with 4 per cent carbonate
solution
Blank
;
.
.
.
.
.
.
.
Ditto
.
.
.
.
.
.
.
5
min.
.
.
.
.
.
.
.
Ditto
.
.
.
.
.
.
.
10 min
.
.
.
.
.
.
.
Ditto
.
.
.
.
.
.
.
20 min
.
.
.
.
.
.
.
Ditto
.
.
.
.
.
.
.
30 min
.
.
.
.
.
.
.
Ditto
.
.
.
.
.
.
.
C. C. of O.1 N. KMnO 4
required
For
estimation
28.70
24.00
10.50
19.35
14.00
10.60
10.70
13.80
16.80
10.65
Calculated
. .
. .
10.46
19.30
13.93
10.60
10.67
13.78
16.74
10.60
Percentage
difference
between
estimated
and cal-
culated
value
. .
. .
+ 0.4
+ 0.3
+ 0.5
+ 0.6
+ 0.3
+ 0.1
+ 0.4
+ 0.5
TABLE II
The effect of different cooking periods with sodium carbonate on oxalate extraction
Observations
1
2
3
4
5
6
7
8
Duration of cooking
15 min. . . . . . . . . . . . .
„ . . . . . . . . . . . .
30 min. . . . . . . . . . . . .
„ . . . . . . . . . . . .
60 min. . . . . . . . . . . . .
„ . . . . . . . . . . . .
120 min. . . . . . . . . . . . .
„ . . . . . . . . . . . .
Per cent
oxalic acid
estimated
1.36
1.37
1.38
1.35
1.37
1.38
1.35
1.37
Percentage
deviation
from the
mean of all
observations
—0.7
Nil
0.7
—1.5
Nil
0.7
—1.5
Nil
Replications and recoveries. The experiment was carried out on the following lines.
(a) Oxalic acid in a sample of paddy straw was estimated from ten independent weighings.
(b) Different known quantities of oxalic acid in the form of sodium oxalate were added to a
series of the same aliquot of a paddy straw extract and the recoveries of the added
oxalate were determined by the proposed method.
(c) To different weighings of exactly 1 gram of a sample of paddy straw, varying quantities
of oxalic acid in the form of calcium oxalate mono-hydrate were added and the re-
coveries were determined.
The results of the experiments are given in Tables III, IV and V and a perusal of these would
show that closely reproducible values and the desired recoveries of the added oxalate are obtained
by the use of the proposed method.
June 1948.]
S. K. TALAPATRA, S. C. RAY AND K. C. SEN 103
TABLE III
Replicate estimation of oxalic acid in paddy straw
Sample No.
1
2
3
4
5
6
7
8
9
10
Per cent
oxalic
acid
1.406
1.406
1.405
1.396
1.425
1.406
1.396
1.406
1.372
1.405
Difference
from the
mean
0.004
0.004
0.003
—0.006
0.023
0.004
—0.006
0.004
—0.030
0.003
Percentage
deviation from
the mean
+ 0.3
+ 0.3
+ 0.2
—0.4
+ 1.6
+0.3
—0.4
+ 0.3
—2.0
+ 0.2
Remarks
(a) Standard doviation : 0.013
(b) Standard error : 0.004
TABLE IV
Recovery of added oxalic acid (as sodium oxalate) from a paddy straw extract
Observations
1
2
3
4
5
Oxalic acid
present in the
aliquot of paddy
straw extract
(mgm.)
14.85
14.85
14.85
14.85
14.85
Oxalic acid
from added
sodium
oxalate
(mgm.)
8.91
17.55
26.73
35.64
44.55
Total oxalic
acid estimated
(mgm.)
23.73
32.08
42.19
50.85
60.30
Oxalic acid
recovered
(mgm.)
8.88
17.23
27.34
36.00
45.45
Percentage
recovery
of added
oxalic
acid
100
98
102
101
102
TABLE V
Recovery of added oxalic acid (as calcium oxalate monohydrate) from paddy straw
Observations
1
2
3
4
5
Oxalic acid
in the straw
(mgm)
16.89
16.89
16.89
16.89
16.89
Oxalic acid from
added calcium
mono-hydrate
(mgm.)
11.71
6.34
10.18
9.88
5.86
Total oxalic
acid estimated
(mgm.)
28.75
23.20
27.23
27.00
22.60
Oxalic acid
recovered
(mgm.)
11.86
6.31
10.34
10.11
5.71
Percentage re-
covery of added
oxalic acid
101
100
102
102
97
104
New Method of Estimation of Oxalic Acid
[Vol. XVIII, Part II
OXALATES IN INDIAN FEEDS AND FODDERS
Since Fincke and Sherman [ 1935 ] have shown that the poor utilization of calcium in spinach
is due to its high oxalic acid content, considerable attention has been paid to the determination of
oxalic acid in vegetables, fruits and other dietary elements generally used for human consumption
[Majumdar and De, 1938 ; Kohman, 1939 ; Rau and Murty, 1942 ]. It seems from the available
analytical data that no survey has been carried out on the oxalic acid content in the feeds and fodders
used for feeding live-stock. As farm animals are herbivorous and oxalic acid is known to occur in
plant materials, the importance of this analytical study is obvious.
By the method already described, a large number of feeding stuffs have been examined for their
oxalic acid content and the results are shown in Table VI.
TABLE VI
Oxalic acid in Indian feeding stuffs
Name of the feeding stuff
A. Green fodder—
1. Lucerne (Medicago sativa) . . . . . . . . . . . .
2. Berseem (Trifolium alexandrinum) . . . . . . . . . . . .
3. Jwar (Andropagon sorghum) . . . . . . . . . . . .
B. Cultivated grasses—
1. Rhodes grass (Chloris gyana) . . . . . . . . . . . .
2. Johnson grass (Sorghum halpense) . . . . . . . . . . . .
3. Sudan grass (Andropogon sorghum var sudanansis)
.
.
.
.
.
.
.
.
4. Napier grass (Penisetum cenchroides) . . . . . . . . . . . .
5. Guinea grass (Panicum maximum)
.
.
.
.
.
.
.
.
.
.
.
.
C. Indigenous grasses—
1. Bhaujura grass (Apluda mutica)
.
.
.
.
.
.
.
.
.
.
.
.
2. Spear grass (Andropogon contortus)
.
.
.
.
.
.
.
.
.
.
.
.
3. Kikiyu grass (Penisetum clandestinum) . . . . . . . . . . . .
4. Dub grass (Cynodon dactylon)
.
.
.
.
.
.
.
.
.
.
.
.
5. Anjan grass (Penisetum cenchroides)
.
.
.
.
.
.
.
.
.
.
.
.
6. Wooly fingur (Paspalam dilatatum)
.
.
.
.
.
.
.
.
.
.
.
.
D. Tree-leaf fodders—
1. Oak (Qurens alba) . . . . . . . . . . . .
2. Ber (Zizyphus jujuba)
.
.
.
.
.
.
.
.
.
.
.
.
3. Pastawanah (Grewia oppositifolia) . . . . . . . . . . . .
Percent oxalic
acid on dry
basis
0.35
0.30
0.45
0.25
0.23
0.44
3.30
2.20
0.27
0.25
0.29
0.44
0.35
2.81
1.13
2.40
5.00
June 1948.]
S. K. TALAPATRA, S. C. RAY AND K. C. SEN 105
TABLE VI—contd.
Oxalic acid in Indian feeding stuffs
Name of the feeding stuff
E. Straws—
1. Paddy straw . . . . . . . . . . . . . .
2. Ditto . . . . . . . . . . . . . .
3. Ditto . . . . . . . . . . . . . .
4. Barley straw . . . . . . . . . . . . . .
5. Wheat straw . . . . . . . . . . . . . .
6. Jwar straw . . . . . . . . . . . . . .
7. Oat straw . . . . . . . . . . . . . .
8. Regi straw . . . . . . . . . . . . . .
F. Grains, cakes and brans—
1. Maize . . . . . . . . . . . . . .
2. Barley . . . . . . . . . . . . . .
3. Mustard cake . . . . . . . . . . . . . .
4. Rape cake . . . . . . . . . . . . . .
5. Groundnut cake . . . . . . . . . . . . . .
6. Wheat bran . . . . . . . . . . . . . . .
Percent oxalic
acid on dry
basis.
1.66
2.05
2.45
0.30
trace
0.31
trace
trace
trace
0.10
0.15
trace
0.19
trace
It is evident from the data in Table VI that oxalic acid is present in Indian feeding stuffs from
negligible to fairly high quantities. Some of the fodders, such as, paddy straw, napier grass and
guinea grass, which are used extensively for cattle feeding are exceptionally rich in oxalic acid. In
view of their high oxalate content, further examination was made of these foodders to study the
distribution of 'soluble' and ' insoluble ' oxalic acid and the minerals with which they may naturally
occur in combination. The results of this examination are shown in Table VII.
TABLE VII
Oxalic acid partition and mineral content in some oxalate-rich fodders
Name of the sample
Paddy straw (1) . . . .
Do.
(2) . . . .
Napier grass (early cut) . . .
Napier grass (dead ripe) . . .
Guinea grass (early cut) . . .
Guinea grass (dead ripe) . . .
Percentage composition on dry basis
Total
oxalic
acid
1.46
1.00
3.05
0.65
2.00
0.80
Soluble
oxalic
acid
1.25
1.35
2.04
0.40
1.10
0.25
Insoluble
oxalic
acid
0.21
0.25
1.01
0.25
0.90
0.35
Ca
0.31
0.28
0.81
0.17
0.66
0.44
Mg
..
0.22
0.51
0.20
0.48
0.35
K
..
2.50
2.90
1.83
2.66
1.16
Na
..
0.07
0.11
0.07
0.17
0.10
From the data in Table VII, it may be seen that (a) the major portion of the total oxalic acid
is present in the soluble form; (b) oxalic acid in these plant materials can combine with two to three
times the calcium present in the plants to form insoluble calcium oxalate and (c) the distribution of
the bases suggests that soluble oxalates are mainly in the form of potassium oxalate and the insoluble
oxalates can be accounted for as calcium or magnesium oxalate or as a mixture of both. From the
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New Method of Estimation of Oxalic Acid
[Vol. XVIII, Part II,
metabolism experiments reported by Talapatra, Ray and Sen [ 1947 ], it would appear that the
insoluble oxalates in paddy straw mainly occur as calcium salt.
The effect of progressive maturity of fodders on oxalate content. It may be seen from the data in
Table VII that early cut napier grass contains more oxalic acid than one cut at the ripe stage. Same
is the case with guinea grass. Since these cultivated fodder plants are fed both at young and mature
stages, a systematic study was carried out to determine their content at progressive stages of matu-
rity. On the basis of theoretical interest, similar study with paddy plant was also included.
Besides oxalic acid, nitrogen and some of the major minerals were analysed in the sample. The
results of this study are given in Table VIII.
TABLE VIII
The effect of progressive maturity on oxalic acid and mineral contents in some oxalate-rich fodders
Name of the
fodder
Paddy
.
.
Napier grass .
Guinea grass .
Stage of cutting
Early . .
Prime . .
Flowering . .
Milk . .
1st ripe . .
Dead ripe . .
Prime . .
Flowering . .
Ripe . .
Dead ripe . .
Prime
.
.
Flowering . .
Ripe . .
Percentage composition on dry basis
Oxalic acid
2.50
1.92
1.78
1.32
1.10
0.90
3.30
1.60
0.68
0.65
2.00
1.10
0.80
Ca
0.38
0.32
0.33
0.32
0.30
0.27
0.43
0.23
0.17
0.16
0.66
0.43
0.44
P
0.46
0.48
0.50
0.44
0.45
0.28
0.79
0.47
0.35
0.32
0.66
0.29
0.20
Mg
0.19
0.19
0.23
0.22
0.21
0.18
0.50
0.32
0.23
0.20
. .
. .
. .
K
3.39
3.00
. .
1.94
1.66
1.49
4.50
2.70
1.88
1.66
2.66
1.91
1.16
Na
0.11
0.07
0.08
0.06
0.07
. .
0.15
0.11
0.07
0.06
. .
. .
. .
N
1.33
1.40
0.94
0.90
0.82
0.35
1.70
0.60
0.37
0.28
1.55
0.63
0.36
The data in Table VIII show that with the progressive maturity of paddy plant, the oxalic acid
content steadily decreases. This decrease appears to be correlated with a similar fall in nitrogen
content. If the figures for nitrogen is considered as the index of vegetative development, it can
reasonably be assumed that the elaboration of the salts of oxalic acid is associated with the vegetative
growth of the plant. Amongst the minerals, potassium alone seems to undergo similar change.
Unlike that of paddy, the data on the analysis of napier and guinea grass show, that, with the progress
from prime to efflorescent stage, the reduction of oxalic acid, nitrogen and potassium is relatively
much more pronounced.
In view of the fact that animals while eating often show preference for the leafy portion of a
fodder, a study was made of the distribution of oxalic acid, nitrogen and minerals in leaf and stem
of napier grass cut at different stages of maturity. The results are set out in Table IX.
June 1948.]
S. K. TALAPATRA, S. C. RAY AND K. C. SEN 107
TABLE IX
Distribution of oxalic acid and minerals in stem and leaf of napier grass
Height of plant
2
ft
.
.
.
5 ft
.
.
.
12 ft
.
.
.
Parts of plant
Leaf . . .
Stem . . .
Whole . . .
Leaf . . .
Stem . . .
Whole . . .
Leaf . . .
Stem . . .
Whole . . .
Percentage composition on dry basis
Oxalic
acid
3.28
3.62
3.50
2.21
1.46
1.60
1.54
0.46
0.68
Ca
0.56
0.36
0.43
0.39
0.11
0.23
0.34
0.11
0.17
P
0.61
0.97
0.79
0.34
0.54
0.47
0.23
0.47
0.35
Mg
0.39
0.48
0.50
0.32
0.29
0.32
0.18
0.20
0.23
K
3.10
5.81
4.50
2.28
2.86
2.70
2.06
2.32
1.88
N
2.58
1.76
1.70
1.12
0.45
0.60
1.00
0.43
0.37
The data in Table IX show that at the early stage, oxalic acid is slightly higher in the stem than
in the leaf. But as the plant grows, the distribution is reversed and the difference in oxalic acid
composition between the stem and the leaf becomes fairly wide. Nitrogen, as well as, calcium are
higher in the leaf, whereas phosphorus is higher in the stem at all stages of growth. High phosphorus
value in the stem appears to be a peculiarity of napier plant.
SUMMARY
1. In view of the limitations in the applicability of the existing methods of estimation of oxalates
in biological materials, a new method has been described which is simple, quick and accurate and
also permits, with minor modification, the partitioning of total oxalates into soluble and insoluble
forms. The method mainly consists in digesting the sample with a strong alkali carbonate solution
which not only breaks the tissue cells, thereby releasing the encased salts, but simultaneously converts
by a process of metathesis, all insoluble oxalates into soluble salts. The total oxalate is thus brought
into the extract. The extract is then separated by filtration and treated in the cold with hydro-
chloric acid to allow precipitation of the extraneous matters dissolved in the alkaline extract. The
acid treated extract is filtered. In the filtrate, oxalate is precipitated by calcium chloride and finally
estimated by the usual permanganate titration.
2. An analytical survey of the total oxalic acid content in commonly red Indian feeds and
fodders shows that it is present from negligible to a very significant quantity in different feeding
stuffs. Some fodders, such as, paddy straw, napier and guinea grass are rich in this substance. In
oxalate-rich fodders, the salt is present both in soluble and insoluble forms. The soluble form, which
occurs mainly as potassium oxalate, represents by far the major portion of the total oxalate. The
total oxalic acid content in these fodders decreases with the progressive maturity of the plant. In
napier grass, at the early stages of its growth, the oxalate content in the stem is higher than in the
leaf. With the maturity, however, this distribution is reversed.
The work described in this paper was carried out in the Animal Nutrition Section, Indian Veteri-
nary Research Institute, Izatnagar.
I
108
New Method 0f Estimation of Oxatic Acid
[Vol. XVIII, Part II,
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