NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
June, 1958] V. N. AMBLE, K. S. KRISHNAN AND J. S. SRIVASTAVA 49
to either of the commonly used sire indices, viz. the intermediate index and the
simple daughters' average index. The corrected indices based on the first lactation
records were worked out corresponding to the average levels of production of dams
of 3,700 lb. for lactation yield, 11.5 lb. for yield per day of lactation, 7 lb. for yield
per day of calving interval and 300 days for lactation period based on the general
level of performance of this herd [Table V]. These indices along with their
standard errors are presented in Table X.
If a superiority of 20 per cent over the herd average is taken as an index of
merit, the bull No. 56 should be considered as highly meritorious since its indices in
respect of all the three yield characters, viz. 4,976 lb. for lactation yield, 14.1 lb. per
day of lactation period and 8.9 lb. per day of calving interval, were above this level.
Sires Nos. 129(0), 188(0) and 136(0) should also be considered as having superior
transmitting ability in respect of the lactation yield, the yield per day of lactation
period and the yield per day of calving interval respectively.
By a similar criterion sire Nos. 255 and 144 might be considered as having very
poor transmitting ability in respect of the lactation yield and the yield per day of
calving interval respectively.
On the basis of the indices for lactation yield the 16 sires used can be grouped
as follows :*
(1) Highly meritorious (indices 20 per cent or more
above the herd average).
(2) Moderately good (indices between 10 per cent
to 20 per cent above the herd average).
(3) Of average calibre (indices within 10 per cent
on either side of the herd average).
(4) Poor (indices between 10 per cent to 20 per cent
below the herd average).
(5) Very poor (indices 20 per cent or more below
the herd average).
Sires Nos. 56 and 129(0).
Sires Nos. 8, 118(0), 238
and 136(0).
Sires Nos. 139, 38, 43(0),
236, 98 and 124(0).
Sires Nos. 65, 282 and 144.
Sire No. 255,
2—RED SINDHI HERD AT THE INDIAN DAIRY RESEARCH INSTITUTE, BANGALORE
In the first part of the paper the results pertaining to the Red Sindhi herd at
the Livestock Research Station, Hosur, have been examined. In this part the
results of a similar statistical examination of the Red Sindhi herd maintained in
Bangalore at the Indian Dairy Research Institute, now the Southern Regional
Station of the National Dairy Research Institute are presented.
*A limitation of the method adopted for comparing the transmitting abilities of the different
bulls is that no correction was made for the noncontemporariness of the different bulls. It was not
possible to evolve valid correction terms for this purpose since the significant differences between
periods observed could themselves have arisen partly due to the differences in the transmitting
abilities of the sires. Since the daughters' records for most of the bulls were spread generally over
more than one period and the changes in successive periods were not uniformly increasing or decrea-
sing it is expected that the bias involved may not be large.
1 AR/58
3
50
STATISTICAL STUDIES ON BREEDING DATA [ ol. XXVIII, Part II,
2.1—FARM AND THE STOCK
The farm attached to the Dairy Research Institute is at a distance of about three
miles from Bangalore City. The climatic conditions of Bangalore are more or less
similar to those of Hosur.
The Sindhi herd at this farm was started in the year 1923 with the purchase of
19 cows from Sind and one bull from Ganeshkhind, Poona. The foundation
stock was augmented by purchase from time to time, mostly from its home tract,
the last set of purchases being made in 1943. Ten heifers were also obtained from
the Wellington Farm, Nilgiris, during 1928. Since the year 1944, there was no
import of fresh blood from outside.
The herd grew progressively in strength from its inception to 1929. In the year
1932 a substantial reduction in the strength of the Sindhi herd was effected by culling
in order to make room for the Gir herd added to the Institute stock that year. From
1932 to 1948 there have been irregular fluctuations in the herd strength. Since
1948 the herd has slowly decreased in strength as may be seen from Table XI.
TABLE XI
Average strength of adult stock
(Sindhi herd at Bangalore)
Year
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
Cows
19
19
51
50
64
105
116
97
113
77
71
72
62
64
66
Breeding
bulls
1
1
1
1
1
1
3
2
3
4
4
4
5
8
8
Year
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
Cows
71
88
74
80
89
89
97
101
95
82
83
68
57
45
44
Breeding
bulls
9
5
6
7
10
9
11
13
13
12
10
10
7
4
4
The farm-bred cows, each with at least one complete lactation record numbered
270 in all up to March, 1952. They belonged to five generations : 92 to the first,
94 to the second, 63 to the third, 20 to the fourth and only one to the fifth. These
and 134 out of 172 foundation cows provided in all nearly 1,450 lactation records
52
STATISTICAL STUDIES ON BREEDING DATA [Vol. XXVIII, Part II,
purchased cows out of 172, 25 farm-bred cows out of 294, 14 heifers out of 412 and 4
bull calves above one year out of 157 died during the period of study.
2.3—BREEDING POLICY
During the early years, the Sindhi herd maintained at the Institute was also
used to raise cross-bred progeny by mating low yielders among the purchased stock
of Sindhi cows to Ayrshire bulls. Cross-bred progeny was also raised from some
farm-bred cows most of which belonged to the first generation. As has been men-
tioned earlier, Sindhi bulls were also used on the cross-bred cows when back-crossing
was desired. Since 1932 the policy was changed to selective breeding purely among
the Sindhi stock and the strength of the cross-bred stock was gradually reduced.
No rigid breeding programme specifying the stages and criteria for culling of animals
and the matings of the selected stock was explicitly laid down.
TABLE XII
Distribution of the farm-bred cows in the Sindhi herd at Bangalore
according to age at culling
Age at culling
Up to 4 years
4 to 5
„
5 to 6 „
6 to 7 „
7 to 8 „
8 to 9
„
9 to 10 „
10 to 11 „
11 to 12 „
12 to 13 „
13 to 14 „
Above 14 „
Number of cows
culled
14
26
20
24
30
25
15
15
12
17
13
11
Percentage
culled
6.3
11.7
9.0
10.8
13.5
11.3
6.8
6.8
5.4
7.6
5.8
5.0
June, 1958] V. N. AMBLE, K. S. KRISHNAN AND J. S. SRIVASTAVA 53
TABLE XIII
Distribution of culled cows in the Sindhi herd at Bangalore
according to the number of lactations completed
Number of lactations
completed
0
1
2
3
4
5
6
7
8 or more
Number of cows
culled
11
32
33
31
37
21
17
14
26
Percentage
4.9
14.4
14.9
14.0
16.7
9.5
7.6
6.3
11.7
Average age
at culling
years—months
4
—
8
4
—
11
6
—
2
7
—
1
8
—
7
9
—
9
11
—
2
12
—
1
13
—
9
Generally speaking, the reasons for culling were more or less similar to those
mentioned in section 1.3 for the Hosur herd. The quantitative description of the
selection practised and the mating system as could be gathered from an examina-
tion of the data are given in the sections which follow.
2.3.1—Selection of female stock
Out of 674 female calves born, as many as 150 were culled before one year of
age, 110 female calves died within a year of birth and the remaining 414 entered
the young stock above one year. Of these, 79, accounting for about 19 per cent
of the young stock, were culled before their first calving. Information relating
to the reasons for culling of individual calves or young stock above one year is not
available from the records maintained.
Low birthweight, non-conformation to the breed type, poor health, low milk
yield of dams and surplus to requirement were reported as some of the reasons for
culling.
Age at culling of the farm-bred adult cows was examined by preparing a frequency
distribution of the 222 culled cows [Table XII]. It was observed that about one-
half of the total number of cows was culled before the age of eight years and one
in four was retained beyond eleven years. The average age at culling was about
eight and a half years.
An examination of the distribution of cows according to number of completed
lactations [Table XIII] indicated that about 48 per cent of the cows were culled
before the completion of the fourth lactation. About one in four cows completed six
54
STATISTICAL STUDIES ON BREEDING DATA [Vol. XXVIII, Part II,
or more lactations in the farm while one in eight was retained for eight or more
lactations. The average number of lactations completed on the farm by a cow was
about four.
The intensity of the selection of cows from lactation to lactation, as measured
by the phenotypic selection differential was 304 lb. which was 12.3 per cent of the
average lactation yield of 2,464 lb. The estimated value was higher than that
for the Hosur herd. This could be attributed to at least two factors. Firstly, the
culling practised in the Bangalore herd was heavier. Secondly, the average calving
interval for this herd was shorter by about 100 days than those in the Hosur herd
which made possible the retention of high yielders for a larger number of lactations.
2.3.2—Selection of male stock
Nineteen farm-bred bulls used for service in the farm were selected from about
650 male calves born on the farm prior to March, 1948. The selection percentage
thus worked out to about three per cent. The farm-bred bulls selected were generally
from high yielding dams.
As in the Hosur herd, the intensity of use of different bulls varied considerably,
the number of progeny born to a bull varying from. 4 to 131 with an average of 48.
The phenotypic selection differential for bulls on the basis of their dams' yields was
1,307 lb. which was 53 per cent of the average lactation yield.
2.3.3—Mating system
As in the case of the Hosur Farm, mating of bulls to closely related cows was
avoided ; but mating of second or more distant cousins was not prohibited. Such
matings were more common in later generations as may be seen from the fact that
the percentage of inbred cows to the total was 16 in the second generation while
in the third and the fourth generations it was as high as 43 and 52 respectively.
Out of the three cows in the fifth generation two were inbred. The inbreeding
coefficient for individual cows varied from 0.006 to 0.25 with an average of 0.069.
The number and the percentage of cows inbred in each generation and their average
inbreeding coefficient are given in Table XIV.
TABLE XIV
Degree of inbreeding in different generations (Sindhi herd at Bangalore)
Order of generation
of cows
Second
Third
Fourth
Fifth
Total number
of cows
97
68
21
3
Inbred cows
Number
16
29
11
2
Per cent
16
43
52
67
Average
inbreeding
cœfficient for
inbred cows
0.102
0.053
0.064
0.062
June, 1958] V. N. AMBLE, K. S. KRISHNAN AND J. S. SRIVASTAVA 55
2.3.4—Breeding performance
The breeding regularity was examined by working out the average age at first
calving and the average calving interval for cows. The age at first calving in the
herd varied generally from two and a half years to five years. There was, however,
one cow which calved for the first time only at the age of six years. The average
age at first calving based on 289 records worked cut to 41.7±0.4 months which
was of the same order as that for the Sindhi herd at Hosur.
The interval between the first two calvings based on 237 cows ranged from 310
to 886 days with an average of 447±8 days. This was 94 days less than the corres-
ponding interval for the Hosur herd. The average interval over 775 records based
on the first seven calvings worked out to 443±5 days. This too was shorter than
the corresponding figure of 521±6 days for the Sindhi herd at Hosur by 78 days.
The average generation interval from dam to progeny was six years and seven
months and that from bull to progeny ten months more. The overall average
generation interval was thus seven years.
The service conception ratio could be worked out from the records for 29 bulls
out of 36 used on the herd. For the remaining seven bulls used prior to 1932 records
were not available. Out of 1,690 services whose results were known, 1,128 were
fruitful giving a conception ratio of 67 per cent.
As has been stated earlier, the Sindhi bulls were used not only on the Sindhi cows
in the farm but also on the cross-bred ones. Including the services performed on
the latter, the average number of services performed by a bull worked out to 17
services per year. With a conception ratio of 67 per cent, the average number of
successful services per bull per year was of the same order as for the Sindhi bulls
at Hosur Farm, which was eleven.
2.4—GENERATIONWISE COMPARISONS
With a view to assessing the overall success of the policy relating to breeding
and management, comparisons of the performance of cows belonging to successive
generations were undertaken in respect of the characters examined for the Red
Sindhi herd at Hosur. Both overall and daughter-dam comparisons were made for
this purpose.
2.4.1—Overall comparisons
For comparing the performance of cows belonging to different generations first
lactation records of farm-bred cows and the first available lactation records, con-
verted to first lactation basis, for foundation cows were studied. The average
56
STATISTICAL STUDIES ON BREEDING DATA [Vol. XXVIII, Part II,
performance, along with the standard error and the coefficient of variation for cows
belonging to the foundation stock and the different farm-bred generations are given in
Table XV. The main conclusions emerging from the results are as follows :
(i) The average lactation period, the lactation yield, the yield per day of
lactation and the yield per day of calving interval were of the same
order for the farm-bred cows as a whole as for the foundation cows. The
average calving interval for the farm-bred cows was, however, significantly
longer by 36 days than that for the foundation cows which was 411 days.
(ii) The first generation of farm-bred cows produced on an average about
one pound less milk per day of lactation than the foundation cows which
gave 9.9 lb. per day, the difference being significant. The average
lactation yield and the yield per day of calving interval were also 2,451 lb.
and 5.8 lb. for the first-generation cows as against 2,655 lb. and 6.4 lb.
respectively for the parental stock. These decreases were, however,
not significant. The calving interval was longer for the former group
by 19 days ; this difference also was less than the critical difference at
5 per cent level of significance.
(iii) The deterioration in the first generation appears to have been partly made
up in the second generation as indicated by the consistent increase in
respect of all the three yield characters, the lactation yield, the yield
per day of lactation and the yield per day of calving interval. These
increases, as also those observed in respect of the lactation period and
the calving interval, were, however, not significant. The age at first
calving alone showed marked change from 39.4 months in the first
generation to 42.1 months in the second.
(iv) The favourable trend in all the three yield characters continued from the
second to the third generation, the averages being 2,952 lb. of lactation
yield, 10.4 lb. per day of lactation and 6.8 lb. per day of calving interval
in the third generation as against 2,570 lb., 9.2 lb. and 6.0 lb. respectively
in the second generation. Of these the increase in the yield per day of
lactation was significant at 5 per cent level. Increases in the lactation
period and the calving interval were not significant but the increase in
the age at first calving from 42.1 months in the second generation to
44.1 months in the third was significant.
(v) The changes observed from the third to the fourth generation were not
significant though the increase of 370 lb. in the average lactation yield
was of the same order as that from the second to the third generation.
The non-significance in the present case is to be ascribed to the relatively
small number of cows in the fourth generation which inflated the standard
error of their average yield.
June, 1958] V. N. AMBLE, K. S. KRISHNAN AND J. S. SRIVASTAVA 57
TABLE XV
Average first lactation performance of Sindhi cows at Bangalore
Foundation stock—
No. of records
Average
S. E.
C. V.
First generation—
No. of records
Average
S. E.
C. V.
Second generation—
No. of records
Average
S. E.
C. V.
Third generation—
No. of records
Average
S. E.
C. V.
Fourth generation—
No. of records
Average
S. E.
C. V.
Over all farm-bred
generations (a)—
No. of records
Average
S. E.
C. V.
Lactation
yield
(lb.)
134
2,655
87
38
82
2,451
165
61
92
2,570
145
54
61
2,952
200
53
20
3,322
301
41
256
2,684
90
55
Yld./day of
lactation
(lb.)
134
9.87
0.24
28
82
8.91
0.39
40
92
9.19
0.33
34
61
10.37
0.42
32
20
10.72
0.82
35
256
9.50
0.21
35
Yld./day of
calving
interval
(lb.)
117
6.38
0.20
34
77
5.80
0.39
59
85
6.05
0.34
53
58
6.81
0.42
41
17
7.58
0.42
42
237
6.26
0.21
52
Lactation
period
(days)
134
260
6
28
82
252
11
40
92
260
10
38
61
271
10
31
20
303
20
30
250
264
6
36
Calving
interval
(days)
117
411
7
19
77
430
10
19
85
445
11
23
58
462
18
31
17
477
33
28
237
447
8
26
Age at first
calving
(months)
..
..
..
..
102
39.4
0.6
11
97
42.1
0.6
15
68
44.1
0.8
14
21
42.9
1.4
15
289
41.7
0.4
13
(a) This includes one cow belonging to the fifth generation.
1AR/58
4
58
STATISTICAL STUDIES ON BREEDING DATA [Vol. XXVIII, Part II,
TABLE XVI
Comparisons of cows belonging to different generations with their dams (Sindhi herd at Bangalore)
Generation
F1
F2
F3
F4
Generation
F1
F2
F3
F4
Lactation yield (lb.)
No. of
pairs
48
94
62
20
M
3073
3082
2996
2645
D—M
—203
—371**
119
911*
S. E.
166
140
221
419
Lactation period (days)
No. of
pairs
48
94
62
20
M
272
260
264
251
D—M
—11
—8
12
48@
S. E.
8.9
9.3
13.4
26.6
Yld /day of lactation (lb.)
No. of
pairs
48
94
62
20
M
11.28
11.31
10.93
10.06
D—M
—0.27
—1.17**
—0.05
1.38
S. E.
0.42
0.32
0.49
0.89
Calving interval (days)
No. of
pairs
42
85
57
17
M
433
410
431
460
D—M
6
30**
43*
23
S. E.
18
10
18
37
Yld./day of calving interval (lb.)
No. of
pairs
42
85
57
17
M
7.33
7.52
7.21
6.45
D—M
—0.40
—1.16**
—0.27
2.12*
S. E.
0.42
0.37
0.52
0.86
Age at first calving (months)
No. of
pairs
—
95
64
20
M
—
38.1
39.7
40.6
D—M
—
4.2**
3.7**
1.2
S. E.
—
0.8
0.9
1.6
D and M denote the averages for the cows in the generation and for their dams respectively.
S.E. denotes the standard error of the difference D—M.
June, 1958 ] V. N. AMBLE, K. S. KRISHNAN AND J. S. SRIVASTAVA 59
2.4.2—Daughter-dam comparisons
The performance of cows in the different generations was also compared with
that of their dams [Table XVI] and the results are discussed below. As in the case
of the Hosur herd, comparisons were made over like lactations, the order of lacta-
tion of the purchased cows having been approximately determined :
(i) The average lactation yield of the cows in the first generation was about
200 lb. less than their dams, but this difference was not significant.
The changes in respect of all the other characters were trivial.
(ii) The milk yield of second generation cows was substantially lower than
that of their dams. The average lactation yield of these cows was
about 370 lb. lower than that of their dams which was of the order of
3,080 lb. The fall in respect of the yield per day of lactation as well as
that per day of calving interval was 1.2 lb. each.
The average age at first calving of the second generation cows was longer
by 4.2 months compared with their dams, average of 38.1 months.
The change in the lactation period was small but the calving interval for the
second generation cows was about a month longer than for their dams.
(iii) The level of production of the third generation cows was not materially
different from that of their dams ; but the breeding efficiency was lower,
as indicated by the higher age at first calving by about four months and
a longer calving interval of about a month and half.
(iv) The fourth generation cows were significantly superior to their dams by
about 900 lb. per lactation and 2.1 lb. per day of calving interval. The
lactation period was longer by 48 days and the yield per day of lactation
was more by 1.4 lb. but these changes were not significant. The
changes in respect of the age at first calving and the calving interval
were also not large.
2.4.3—Generationwise comparisons adjusted for annual variations
The comparisons made in earlier sections of cows belonging to different genera-
tions were likely to have been affected by changes occurring from time to time in the
management and other environmental factors. These effects were sought to be
minimised by adopting the method of analysis of variance by fitting constants. As
in the case of the Sindhi herd at Hosur, the records made in different years were
grouped in successive periods of about five years each. The analysis indicated that
the interaction between generation and period was negligible.
From the adjusted analysis of variance (Table XVII) it was seen that period to
period variation taking due account of the generation differences was significant.
Although the differences between generations, adjusted for period to period variation,
were not significant, progressive improvement was observed in successive generations,
the average increase in lactation yield being of the order of about 170 lb. per genera-
tion [vide Table XVIII]. The non-significance of the overall variation between
generations is to be attributed to the large residual variation.
60
STATISTICAL STUDIES ON BREEDING DATA [Vol. XXVIII, Part II,
TABLE XVII
Adjusted analysis of variance for periods and generations of Red Sindhi cows at Bangalore
(First lactation yield in units of 10 lb.)
Source of variation
Between periods (eliminating generations)
Between generations (eliminating periods)
Residual between cells (Interaction of generation and
period)
Within cells (error)
D.F.
4
3
7
240
M.S.
47,464
10,773
22,496
20,303
V.R.
2.33
Not significant
„
TABLE XVIII
Adjusted period and generation average for lactation yields of Red Sindhi cows at
Bangalore
Period
1926-30
1931-35
1936-40
1941-45
1946-51
Number of
records
21
40
65
76
53
Adjusted
average
(lb.)
2,592
2,835
2,456
2,458
3,203
Order of
generation
F 1
F 2
F 3
F 4
..
Number
of cows
82
92
61
20
..
Adjusted
average
(lb.)
2,509
2,656
2,839
3,024
..
2.4.4—Overall conclusions
The trends observed in the performance of cows belonging to different genera-
tions in the course of the analysis described in the above sections may be briefly
summarised as follows:
(a) There was a progressive overall improvement in the milk production of cows
from the first to the fourth generation. The average increase per generation
was of the order of 290 lb. per lactation and about 0.6 lb. per day of lactation as
well as per day of calving interval.
(b) The average yield of cows, after allowing for the changes from generation to
generation, was fairly constant during the period from 1926 to 1945, but was higher
by about 660 lb. for the period 1946 to 1951.
(c) When allowance was made for the variation from period to period, the
estimate of the increase per generation in the average lactation yield was reduced to
170 lb.
(d) The lactation period steadily increased from 252 days in the first generation
to 303 days in the fourth.
(e) The increase in the lactation period was accompanied by a corresponding
increase in the calving interval. The calving interval for the fourth generation cows
was about a month and a half longer than the first generation average of about 14
months.
(f) The average age at first calving was 39.4 months for the first generation of
farm-bred cows, but was longer by 2.7 months for the second generation and 4.7
months for the third generation.