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between the average values of columns 6A and 8A and of columns 5A and 7A represents the average
percentage increase due only to increasing the frequency of milking from two to four times.
It will be noted from columns 6A and 8A, cows under four times milking, that increases in yield
varying from 10.32 to 51.19 per cent have been obtained in the second and third lactations which
may be taken as normal behaviour in milch animals advancing toward their prime or optimum age
of production coupled with four times milking. Columns 5A and 7A show, however, that in the cases
of animals continued on two times milking, this increase has occurred in only one case, viz. 'Lasni'
in her third lactation and this on a lower scale than the lowest of the range of variation in the case
of cows under four times milking. In all other cases there has been a distinct fall in production in
the second and third lactations. In the case of 'Qabdi' this was to the extent of 39.53 per cent
in the second lactation which was continued in the third to the extent of 11.60 per cent. Under two
times milking it would appear that the normal development of milk secretion in Indian cows does
not take place whether the optimum conditions of feed and other items of management are provided
or not.
The difference between the average yields of the 'four-time milkers' and 'two-time milkers
was calculated by taking into consideration the average values of columns 6 and 8 (average yields
of 'four-times milkers' in the second and third lactations respectively) and of columns 5 and 7
(average yields of 'two-time milkers' in the second and third lactations respectively).
The milk yield data of the second set of eleven cows were considered as another group for the
purpose of statistical examination as shown in Table II. The same procedure of analysis was
applied to this group.
TABLE II
Average milk yield (wet period) in lb. per day of eleven cows milked four times a day in their pre-experi-
mental first lactation.
Name of cow
Milked 2
times under
experiment
1
Poli . .
Parsanni
Rashi
Manfi
Lila .
Partapi
Milked 4
times under
experiment
2
Mitri
Machkani .
Phijji
Ramdi
Rahil
..
During pre-
experimental
period
1st Lactation
Milked 4 times
3
21.21
21.03
19.37
18.08
17.46
16.76
4
21.71
21.11
18.35
18.31
18.20
..
During experimental period
2nd Lactation
Milked
2 times
5
18.78
18.04
15.58
16.27
15.25
15.92
Milked
4 times
6
22.67
Aborted
20.19
19.61
22.47
..
3rd Lactation
Milked
2 times
7
16.17
21.02
13.12
12.55
18.36
17.83
Milked
4 times
8
24.47
29.64
33.44
18.85
20.07
..
4th Lactation
Milked
2 times
9
14.94
20.43
13.62
15.26
14.66
18.15
Milked
4 times
10
25.88
30.72
31.67
21.69
25.75
..
Mean
2 times milking
16.44±0.833
*F=43.97
4 times milking
24.70±0.945(a)
Percentage increase (+) or decrease (—)
over first lactation.{
5
A
—11.40
—14.22
—19.57
—10.01
—12.66
—5.01
6
A
+4.42
..
+10.03
+ 7.10
+ 23.46
..
7
A
—23.76
—0.05
—32.27
—30.59
+5.15
+6.38
8
A
+ 12.71
+ 40.41
+ 82.23
+ 2.95
+ 10.27
..
9
A
—29.56
—2.85
—29.69
—15.60
—16.04
+ 8.29
10
A
+ 19.21
+ 45.52
+ 72.59
+ 18.46
+ 41.48
..
—12.97 ± 1.472
*F=36.58
27.92 ± 5.071 (b)
(a) Represents in increase of 50.8 per cent over two times milking.
(b) Represents a decrease of 40.9 per cent due to reducing the frequency of milking from 4 to 2 times.
*F=Variance ratio, highly significant in both the cases.
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