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ORIGINAL ARTICLES
STUDIES ON CALCIUM AND PHOSPHORUS IN MILK
AND FEEDS OF SAHIWAL COWS FROM PRECALVING
PERIOD TO THE END OF LACTATION
By M. L. MATHUR and S. V. DESAI, Indian Agricultural Research Institute,
New Delhi
(Received for publication on 6 April 1951*)
(With 13 text-figures)
I N our previous publication [1945], we had pointed out the trend of calcium
and phosphorus contents of pre-milk and milk after lactation in Sahiwal cows.
The present paper is the result of the continuation of the studies in thirteen cows
from precalving period to the end of lactation. The composition of milk in high,
medium and low milking cows, with respect to any possible effect of the various feeds
on it, was studied throughout the pre-lactation, lactation and gestation period.
The object was to study if there were and if so to what extent, variation in the
percentage, ratio and total outgo of calcium and phosphorus in relation to the yield
of milk, age and stage of lactation.
Four high milking, four medium milking and five low milking cows, whose par-
ticulars are given in Table I, were selected for the experiment.
TABLE I
Particulars of the cows
Group
I
II
III
Names of the cows
Firookee
Cholina
Tashkam
Rajkhati
Nalchamina
Nachreng
Firchrama
Chansuri
Nachrengee
Naroochi
Lefinchni
Nalkram
Hanchalma
High milkers
Medium milkers
Low milkers
Number
of
lactation
3
4
2
5
2
1
3
9
1
1
1
1
1
Lactation
milk
yield
in lb
9,060
7,555
7,620
7,560
4,135
6,141
7,118
6,610
4,656
4,359
4,649
4,410
3,532
* Revised in July 1953.
221
7 AR/53
222 STUDIES ON CALCIUM AND PHOSPHORUS IN MILK [Vol. XXIII, Part IV,
Some of these cows were from the same sire. Nalchamina, Nachrengee, Nal-
kram, Naroochi and Nachreng were from one sire. Chansuri and Cholina were
from another sire.
Cows were taken for the experiment as their calving time approached. Ex-
perimental period began few days before calving, when the pre-milk was being taken
out. During the lactation period, the cows were milked four times a day and fed
four times a day at the time of milking.
The various fodders and their quantities consumed by the cows throughout
the experimental period are set forth in Table II.
TABLE II
Various fodders given to the cows
Number
I
II
III
IV
V
Period
1 December 1943 to 12 February
1944
13 to 20 February 1944
21 to 29 February 1944
1 to 31 March 1944
1 to 10 April 1944
Fodder
Bhusa
Cow peas hay
Green jowar
Green berseem
Green oats
Bhusa
Green berseem
Green oats
Bhusa
Green berseem
Green oats
Jowar silage
Green berseem
Green oats
Jowar silage
Green lucerne
Bhusa
Green berseem
Green oats
Jowar silage
Green cowpeas
Lb.
per day
2
4
16
25
3
4
29
11
5
29
11
11
28
11
20
5
4
22
3
22
4
December, 1953 ]
M.
L.
MATHUR
AND
S.
V.
DESAI
223
TABLE II—(contd.)
Various fodders given to the cows—(contd.)
Number
VI
VII
VIII
IX
X
XI
XII
Period
11 to 30 April 1944
1 to 15 May 1944
16 to 31 May 1944
1 June 1944 to 31 August 1944
1 September 1944 to 31 October 1944
1 to 30 November 1944
1 to 31 December 1944
Fodder
Green berseem
Green oats
Jowar silage
Bhusa
Green berseem
Green oats
Jowar silage
Green berseem
Jowar silage
Berseem hay
Berseem hay
Bhusa
Green lucerne
Mixed maize, bajra and cowpeas
Bhusa
Green cowpeas
Green jowar
Bhusa
Green cowpeas
Green jowar
Bhusa
Green jowar
Berseem hay
Green berseem
Green lucerne
Green cowpeas
Lb.
per day
20
3
16
1
16
1
19
10
20
5
3
4
4
35
4
18
40
4
10
50
4
24
4
6
6
10
224 STUDIES ON CALCIUM AND PHOSPHORUS IN MILK [ Vol. XXIII, Part IV,
TABLE II—(contd.)
Various fodders given to the cows—(contd.)
Number
XIII
XIV
XV
XVI
Period
1 to 31 January 1945
1 February 1945 to 31 March 1945
1 to 30 April 1945
1 May 1945 to 10 June 1945
Fodder
Bhusa
Green berseem
Green lucerne
Sugarcane
Jowar silage
Bhusa
Green berseem
Green lucerne
Sugarcane
Jowar silage
Green berseem
Bhusa
Jowar karbi
Jowar silage
Rhodes grass
Green sugarcane
Bhusa
Green berseem
Jowar karbi
Rhodes grass
Berseem hay
Lucerne plus Rhodes
Lb.
per day
6
12
10
20
15
6
20
16
15
10
30
3
2
5
10
8
3
30
2
10
4
10
The daily yield of milk, calcium and phosphorus percentage and their ratio,
total CaO and P 2 O 5 in milk and feed, and the percentage of CaO and P 2 O 5 secreted in
milk from the total intake, for the precalving and lactation periods were calculated.
December, 1953]
M.
L.
MATHUR
AND
S.
V.
DESAI
225
Cholina 4th Lactation (7544 lb.)
Ferookee 3rd Lactation (9060 lb.)
226 STUDIES ON CALCIUM AND PHOSPHORUS IN MILK [Vol. XXIII, Part IV,
Rajkhati 5th Lactation (7560 lb.)
Tashkam 2nd Lactation (7620 lb.)
December, 1953]
M.
L.
MATHUR
AND
S.
V.
DESAI
227
Nachreng 1st Lactation (6139 lb.)
Nalchamina 2nd Lactation (4135 lb.)
228 STUDIES ON CALCIUM AND PHOSPHORUS IN MILK [Vol. XXIII, Part IV,
Chansuri 9th Lactation (6587 lb.)
Firchrama 3rd Lactation (7118 lb.)
December, 1953]
M.
L.
MATHUR
AND
S.
V.
DESAI
229
Naroochi 1st Lactation (4359 lb.)
Nachrenge 1st Lactation (4645 lb.)
230 STUDIES ON CALCIUM AND PHOSPHORUS IN MILK [Vol. XXIII, Part IV,
Nalkram 1st Lactation (4410 lb.)
Lefinchni 1st Lactation (4649 lb.)
December, 1953]
M.
L.
MATHUR
AND
S.
V.
DESAI
231
Hanchalma 1st Lactation (3532 lb.)
232 STUDIES ON CALCIUM AND PHOSPHORUS IN MILK [ Vol. XXIII, Part IV,
Graphs for each cow, showing curves for CaO and P 2 O 5 per cent in milk, calcium
phosphorus ratio, total calcium oxide and phosphorus pentoxide in the milk and the
daily milk yield during the precalving period and throughout the lactation are shown
in Fig. 1 to 13.
DISCUSSION OF THE RESULTS
Calcium percentage of milk
The percentage of Calcium was very low about 0.02 to 0.11 per cent on the first
day of taking out pre-milk and tended to increase as the time of calving approached
and continued to increase for a week or two after calving. As the milk yield increased
with the approach of flush period the percentage of calcium fell. It remained at
low level for some time and then the tendency was to increase and remain more or
less constant for a fairly long period of lactation. It then again increased with the
start of gestation period and shrinkage in the milk yield.
Phosphorus percentage of milk
The percentage of phosphorus was fairly high about 0.1 to 0.3 per cent in the
pre-milk on the first day of pre-milking and continued to increase, reaching the
maximum (0.30 to 0.37 per cent) a day or two before calving (in few cases after also)
and then decreased. The tendency to decrease continued for about two weeks.
It remained at low level for some time and then tended to increase and remain
more or less constant and the tendency was to run parallel to calcium curve.
Calcium : Phosphorus ratio in milk
The CaO : P 2 O 5 ratio was high (1.20 to 4.0) and fluctuating in the pre-milk.
After calving, there was sharp fall in the ratio. It remained low during the flush
period and then increased slightly and remained more or less constant throughout
the lactation period.
Calcium and phosphorus in the milk
The curves for total calcium and phosphorus in milk run more or less parallel.
Since the CaO and P 2 O 5 contents of the milk depend more on the yield of milk than
on the CaO and P 2 O 5 per cent, they are similar and run parallel to the curves of milk
yield. While the trend of the curves of CaO and P 2 O 5 per cent is to go up, the curves
for total CaO and P 2 O 5 in milk is slanting upward.
Milk yield
The curves for the milk yields have been shown for each cow. After calving,
there is a sharp rise in the curves. The milk yield remains at that level for 8 to 18
weeks and then the shrinkage is visible by the slanting down of the curves.
Table III shows the average milk yield, CaO and P 2 O 5 per cent, total calcium
oxide and phosphorus pentoxide in milk in the (i) pre calving period (ii) before flush
period (iii) during flush period and (iv) after flush in case of high, medium and low
milking cows.
December, 1953 ]
M.
L.
MATHUR
AND
S.
V.
DESAI
233
TABLE III
Average milk yield, its composition and the total CaO and P 2 O 5 in milk in the
various stages of lactation
Stage of lactation
1. Pre-calving
2. Before flush
3. During flush
4. After flush
1. Pre-calving
2. Before flush
3. During flush
4. After flush
1. Pre-calving
2. Before flush
3. During flush
4. After flush
Average
milk yield
in lb.
CaO
per cent
Total
CaO in
milk
in gm.
Group I. High milkers
3.4
25.4
34.6
22.1
0.118
0.173
0.169
0.171
2.23
20.12
26.41
17.01
Group II. Medium milkers
2.9
25.3
32.0
17.2
0.124
0.171
0.170
0.173
2.07
19.72
24.53
13.32
Group III. Low milkers
3.4
20.7
22.0
12.4
0.123
0.174
0.171
0.181
2.26
16.38
17.13
10.13
P 2 O 5
per cent
0.280
0.288
0.209
0.217
0.242
0.273
0.218
0.225
0.269
0.273
0.215
0.227
Total
P 2 O 5
milk
in gm.
4.28
32.80
32.67
21.61
3.59
31.24
31.37
17.45
4.38
25.24
21.51
12.73
Ratio
CaO :
P 2 O 5
1 : 2.45
1 : 1.69
1 : 1.24
1 : 1.27
1 : 2.05
1 : 1.61
1 : 1.28
1 : 1.30
1 : 2.37
1 : 1.58
1 : 1.26
1 : 1.25
It appears that calcium and phosphorus contents in the milk in different groups
of cows are about the same. Calcium is low 0.12 per cent in the pre-milk and
gradually increased to 0.17 per cent afterwards. Phosphorus was high 0.28 per
cent in the pre-milk and came down to 0.22 per cent afterwards. The average
CaO : P 2 O 5 ratio in the milk was as high as 1 : 2.4 in the pre-milk and reached a
lower value of 1 : 1.3 in normal milk. The calcium and phosphorus contents of
the milk during the flush period were lower than that before flush and after flush
period.
Two cows Tashkam and Rajkhati were under study in different lactations.
Their average daily milk yield, composition of milk and CaO : P 2 O 5 ratio during the
sa me period in the two different lactations have been compared in Tables IV and V.
234 STUDIES ON CALCIUM AND PHOSPHORUS IN MILK [ Vol. XXIII, Part IV,
TABLE IV
Comparative data of the cow Tashkam in 14 to 17 week of the first and second
lactations
Total lactation yield in lb.
8,621
7,620
Average
yield of
milk per
day in lb.
31
30
Average
CaO per cent
in milk
0.144
0.149
Average
P 2 O 5 per
cent in
milk
0.189
0.192
Ratio
CaO : P 2 O 5
1 : 1.32
1 : 1.29
Number of
lactation
1
2
TABLE V
Comparative data of the cow Rajkhati in 9 to 12 week of fourth and fifth lactation
Total lactation yield in lb.
9,061
7,560
Average
yield of
milk per
day in lb.
37
33
Average
CaO per cent
in milk
0.159
0.174
Average
P 2 O 5
in milk
0.174
0.186
Ratio
CaO : P 2 O 5
1 : 1.09
1 : 1.07
Number of
lactation
4
5
In Tashkam the average daily milk yield, CaO and P 2 O 5 percentages and the
CaO : P 2 O 5 ratio were practically the same in the first and second lactations. In
Rajkhati the average daily milk yield was four pounds less in the fifth lactation and
the calcium and phosphorus contents of the milk were slightly higher. This cow
gave 1,500 pounds less milk in the fifth lactation than the previous one. The ratio
of calcium and phosphorus was the same.
The total calcium and phosphorus in milk under the various feeds (feed 100)
have been given in Tables VI and VII. These indicate that when more than 20 gm.
CaO and 21 gm. P 2 O 5 was given out in the milk out of 100 gm. supplied in the feed
during the various fodder periods, negative calcium and phosphorus balances occur-
red in the cows. The fodders berseem, lucerne, oats, cowpeas, jowar, maize, bajra,
Rhodes grass, were of good quality. Hay prepared from berseem, lucerne and cow-
peas and silage prepared from jowar were also fed along with the fresh green fodders.
But these were not found to be sufficient to meet the mineral requirements of the
cows and the need for mineral supplement was all along felt. The different fodders
did not seem to alter the composition of milk (calcium and phosphorus percentages).
December, 1953 ]
M.
L.
MATHUR
AND
S.
V.
DESAI
235
TABLE VI
Sum mean CaO in grams present in the milk during the various fodder periods (feed 100 gm. CaO)
Period of
fodder
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15 and 16
First group
Firokee
1
16.05
29.25
37.30
34.23
27.55
50.16
51.35
27.65
25.65
22.58
Cholina
2
16.40
30.28
55.31
45.42
26.14
23.49
21.20
16.83
14.32
7.61
Tashkam
3
26.84
44.34
31.35
29.71
19.57
19.12
19.43
12.79
12.13
Rajkhati
4
22.51
32.56
27.65
30.24
20.82
20.59
10.61
Second group
Nalcha-
mina
5
1.23
14.34
33.27
17.01
7.86
Nachreng
6
0.03
4.93
30.03
23.36
25.32
24.75
15.74
11.80
4.87
Firchr-
ama
7
0.24
18.33
24.40
45.84
48.40
45.49
23.82
21.93
10.80
9.95
7.74
Chansuri
8
15.12
27.29
47.40
50.48
26.95
24.35
17.94
4.19
11.49
6.31
Third group
Nachre-
ngee
9
11.52
15.17
23.39
18.C9
12.51
28.74
29.79
26.92
18.61
15.60
14.89
Naroochi
10
14.77
20.67
19.80
16.06
12.13
33.88
25.18
12.89
11.48
10.72
Lifinchni
11
11.95
16.31
22.87
17.14
13.77
27.00
30.45
20.42
16.61
14.48
Nalkram
12
1.63
20.96
22.22
20 .8 8
19.29
35.25
22.45
16.49
14.72
11.73
6.12
4.65
Han-
chalma
13
0.16
17.88
19.28
36.55
37.56
31.41
15.55
7.49
6.34
4.90
NOTE.—The underlined figures indicate negative balances in cows during the periods.
236 STUDIES ON CALCIUM AND PHOSPHORUS IN MILK [ Vol. XXIII, Part IV,
TABLE VII
Sum mean P 2 O 5 in gm. present in the milk during the various fodder periods (feed 100 gm. P 2 O 5 )
Period of
fodder
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15 and 66
Firokee
1
24.87
33.98
33.84
30.78
25.57
31.81
36.65
35.05
28.27
36.01
First group
Cholina
2
18.90
29.39
32.96
34.58
29.80
28.38
24.46
26.68
22.96
22.80
Tashkam
3
27.10
34.30
31.43
29.93
22.44
25.23
23.49
22.10
18.79
Kajkhati
4
24.14
30.42
28.68
30.35
30.37
26.60
23.01
Nalch-
mina
5
2.30
25.78
33.17
20.51
20.82
Second group
Nachreng
6
0.09
0.11
38.08
28.82
34.44
28.71
25.95
17.77
14.39
Firchr-
ama
7
0.56
23.62
26.33
28.65
32.52
29.90
27.05
25.58
17.51
20.64
26.32
Chausuri
8
18.23
28.23
30.86
33.25
29.75
26.78
26.20
24.56
21.35
18.71
Nachren-
gee
9
88.67
30.43
33.27
24.91
19.26
19.87
22.90
22.54
21.48
18.37
22.93
Third group
Naroochi
10
25.51
24.63
24.26
17.60
14.64
18.49
20.66
17.30
13.40
17.95
Lifinchni
11
21.42
29.63
27.95
24.54
17.64
19.96
26.08
24.72
21.48
21.95
Nalkuam
12
5.30
35.89
28.66
26.14
21.25
22.89
19.32
18.33
16.04
16.90
10.57
11.89
Han-
chalma
13
0.40
23.69
19.97
22.75
28.19
29.81
19.56
20.57
24.48
18.04
NOTE.—The underlined figures indicate negative balances in cows during the periods.
December, 1953 ]
M.
L.
MATHUR
AND
S.
V.
DESAI
237
From our experience of the balance experiments [1953] conducted with cows
yielding between 30 to 40 pounds milk per day, it was found that equilibrium was
maintained, as long as, out of every 100 gm. CaO in the feed, 20 gm. were utilised in
milk or retained in body and 80 gm. were voided in faeces and urine. It may therefore
be concluded that for every 20 gm. CaO given out in the milk, 100 gm. CaO should be
present in the feed. If more than 20 gm. are passed out in the milk when the feed
contains only 100 gm. CaO equilibrium is disturbed and negative balance occurs,
since 80 gm. or 80 per cent of the intake are invariably voided in the faeces and urine.
Similarly in the case of phosphorus also out of 100 gm. P 2 O 5 in the feed, 79 gm. are
voided in faeces and urine and 21 gm. are utilised in the milk production. Thus
for every 21 gm. P 2 O 5 given out in the milk, at least 100 gm. are necessary in the
feed. If more than 21 per cent of the intake of P 2 O 5 in the feed, are present in the
milk negative balance occurs.
The data of the three groups of cows, high milkers, medium milkers and low
milkers, has been examined in the light of the above conclusions from pre-calving
period to the end of lactation ; and set forth in Tables VIII, IX, X and XI. In the
Table VIII, CaO and P 2 O 5 balances of each cow has been shown datewise dividing the
whole lactation into three periods. In Table IX the number of days of positive
and negative balances of CaO and P 2 O 5 in the three periods have been shown. In
Table X are shown the number of days, each cow was in positive and negative calcium
and phosphorus balances. Average balances of CaO and P 2 O 5 of the three groups of
cow have been shown in Table XI.
TABLE VIII
A. Calcium oxide balance
Names of cows
Firokee
Cholina
Tashkam
Rajkhati
Nalchamina
Nachreng
Firchrama
Chansuri
Nachrengee
Naroochi
Lefinchi
Nalkram
Hanchalma
+Balance
21-12-43 to 4-1-44
3-3-44 to 16-3-44
19-4-44 to 24-4-44
24-7-44 to 7-8-44
13-5-44 to 26-5-44
11-5-44 to 1-6-44
23-2-44 to 13-3-44
3-3-44 to 20-3-44
17-12-43 to 17-2-44
14-12-43 to 5-4-44
14-12-43 to 1-1-44
10-2-44 to 15-2-44
24-2-44 to 17-3-44
—Balance
5-1-44 to 1-11-44
17-3-44 to 19-10-44
25-4-44 to 19-9-44
8-8-44 to 22-2-45
27-5-44 to 10-10-44
2-6-44 to 26-12-44
14-3-44 to 2-10-44
21-3-44 to 14-9-44
18-2-44 to 17-5-44
6-4-44 to 10-5-44
2-1-44 to 13-1-44
16-2-44 to 22-5-44
18-3-44 to 19-6-44
+Balance
....
20-10-44 to 11-1-45
20-9-44 to 20-2-45
23-2-45 to 7-6-45
11-10-44 to 21-11-44
27-12-44 to 27-3-45
3-10-44 to 8-1-45
15-9-44 to 11-1-45
18-5-44 to 25-10-44
11-5-44 to 18-10-44
14-1-44 to 1-11-44
23-5-44 to 11-12-44
20-6-44 to 11-1-44
7 AR/53
3
238 STUDIES ON CALCIUM AND PHOSPHORUS IN MILK [ Vol. XXIII, Part IV,
Names of cows
Firokee
Cholina
Tashkam
Rajkhati
Nalchamina
Nachreng
Firchrama
Chansuri
Nachrengee
Lefinchi
Naroochi
Nalkram
Hanchalma
B. P 2 O 5 balance
+Balance
21-12-44 to 2-1-44
3-3-44 to 16-3-44
19-4-44 to 22-4-44
24-7-44 to 6-8-44
13-5-44 to 23-5-44
11-5-44 to 27-5-44
23-2-44 to 10-3-44
3-3-44 to 15-3-44
17-12-43 to 27-12-43
14-12-43 to 27-12-43
14-12-43 to 19-12-43
10-2-44 to 13-2-44
24-2-44 to 5-3-44
—Balance
3-1-44 to 1-11-44
17-3-44 to 14-12-44
23-4-44 to 19-12-44
7-8-44 to 22-2-45
24-5-44 to 3-10-44
28-5-44 to 13-2-45
11-3-44 to 30-10-44
16-3-44 to 14-12-44
28-12-43 to 15-1-44
28-12-43 to 17-1-44
20-12-43 to 7-1-44
14-2-44 to 8-5-44
6-3-44 to 3-7-44
+Balance
....
15-12-44 to 11-1-45
20-12-44 to 20-2-45
23-2-45 to 7-6-45
4-10-44 to 21-11-44
14-2-45 to 27-3-45
31-10-44 to 8-1-45
15-12-44 to 11-1-45
16-1-44 to 25-10-44
18-1-44 to 1-11-44
8-1-44 to 18-10-44
9-5-44 to 11-12-44
4-7-44 to 11-12-44
TABLE IX
The number of days of + and — balances of CaO and P 2 O 5 in three periods
Names of cows
Firokee
Cholina
Tashkam
Rajkhati
Nalchamina
Nachreng
Firchrama
Chansuri
Nachrengee
Naroochi
Lefinchi
Nalkram
Hanchalma
Number of
lactation
3
4
2
5
2
1
3
9
1
1
1
1
1
Milk
yield in lb.
9,060
7,555
7,620
7,560
4,135
6,141
7,118
6,010
4,645
4,359
4,649
4,410
3,532
+balance
CaO
—balance
High milkers
14
13
5
14
300
216
147
198
Medium milkers
13
21
18
17
130
207
202
177
Low milkers
62
112
18
5
21
88
34
11
95
93
+balance
..
83
153
104
41
90
97
118
160
160
291
202
174
+balance
12
13
3
13
10
16
15
12
10
5
13
3
9
P 2 O 5
—balance
302
272
240
199
132
261
233
273
18
18
20
83
119
+balance
..
27
62
104
48
41
69
27
282
283
287
216
160
December, 1953 ]
M.
L.
MATHUR
AND
S.
V.
DESAI
239
TABLE X
The total number of days of + and — balances of CaO and P 2 O 5
Names of cows
Firokee
Cholina
Tashkam
Rajkhati
Nalchamina
Nachreng
Firchrama
Chansuri
Nachrengee
Naroochi
Lefinchi
Nalkram
Hanchalma
Number of
lactation
3
4
2
5
2
1
3
9
1
1
1
1
1
Milk yield
in lb.
CaO
+balance
High milkers
9,060
7,555
7,620
7,560
14
96
158
118
Medium milkers
4,135
6,141
7,118
6,610
Low milkers
4,645
4,359
4,649
4,410
3,532
54
111
115
135
222
272
309
207
195
—balance
300
216
147
198
136
207
202
177
88
34
11
95
93
P 2 O 5
+balance
12
40
65
117
58
57
84
39
292
288
300
219
169
—balance
302
272
240
199
132
261
233
273
18
18
20
83
119
TABLE XI
The number of days of + and — balances of CaO and P 2 O 5 in the three groups
Group of cows
I. High milkers
II. Medium milkers
III. Low milkers
CaO
+balance
97
104
241
—balance
215
181
64
P 2 O 5
+balance
59
60
254
—balance
253
225
52
It would appear from Table X that among the high milkers, Firokee which
gave the maximum amount of milk, 9,060 lb. in the whole lactation was in positive
calcium balance for fourteen days and in negative calcium balance for 300 days in
the lactation period. It was in positive phosphorus balance for 12 days and in
negative balance for 302 days. The other three cows Cholina, Tashkam and Rajkhati
with the lactation yields, of 7,555, 7,620, and 7,560 pounds respectively, were in
positive calcium balance for 96, 158, 118 days and in positive phosphorus balance
for 40, 65 and 117 days. The rest of the days they were in negative balances.
7 AR/53
4
240 STUDIES ON CALCIUM AND PHOSPHORUS IN MILK [ Vol. XXIII, Part IV,
In the medium and low milkers, the number of days in positive balances are
more and in the negative balances much less.
Table XI would show that the high milkers were in positive calcium balance,
for 97 days and in positive phosphorus balance for 59 days only. For the rest of the
days calcium and phosphorus was lost from the body. The cows in this group were
second, third, fourth and fifth calvers. The average figures of positive and negative
balance of the medium and low milkers are given.
The groups of high and medium milking cows remained in negative calcium
and phosphorus balances for a fairly long time during the lactation period and the
losses from the body were not negligible. Even in the low milking group, the cows,
doing about 4,500 lb. in the whole lactation, lost calcium and phosphorus during the
flush period for seven to nine weeks, when the daily milk yield was about 25 lb.
or more per day, on a good feed, but not supplemented by mineral salts. The lossses
of calcium and phosphorus were apparent when its amounts in the feed were less
than 75 and 80 gm. respectively. Since only a limited fraction of the minerals was
available to the animals, an adequate intake was necessary in the feed.
The necessity of feeding mineral supplement is therefore felt for a small period
in low milkers, greater period in medium milkers and almost throughout the lacta-
tion period in the case of high milkers.
The cow secretes about 4 gm. CaO and 5 gm. P 2 O 5 in 5 lb. of milk. Therefore
with an intake of 75 gm. CaO and 80 gm. P 2 O 5 after the daily milk yield exceeds
20 lb., it becomes necessary to supply the cow with 20 gm. CaO and 25 gm. P 2 O 5
in the feed with every increase of 5 lb. in the milk yield.
In our experiments [1953] we found that CaO : P 2 O 5 ratio varying from 1.0 to
2.0 maintained positive calcium balance but not phosphorus balance. The phosphorus
assimilation was larger in high phosphorus period when the CaO : P 2 O 5 ratio was
about 1.0 to 1.25.
Keeping these into consideration, the mineral mixture should be such as to
provide an optimum CaO : P 2 O 5 ratio in the feed. A mineral mixture of the following
composition is considered very suitable.
Sterilized bone-meal
Finely ground chalk
Di-calcium phosphate
Sulphur
Common salt (NaCl)
Oxide of iron
Potassium iodide
Finely ground anhydrous copper sulphate
Finely ground cobalt chloride
Manganese sulphate
50 lb.
15 lb.
10 lb.
3 lb.
20 lb.
2 lb.
4 oz.
0.5 oz.
0.1 oz.
4 oz.
In case the phosphorus in the fodders is not sufficient, di-calcium phosphate
may be replaced by sodium phosphate and chalk by bone-meal. Extra sodium
chloride, according to the needs of the animals whether growing or milch cattle, is
also provided as salt licks or half to one ounce mixed in the concentrate feed.
The quantity of sulphur is adjusted according to the sulphur contents of the
ration and common salt substituted in its place.