NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
34
STATISTICAL STUDIES ON BREEDING DATA [Vol. XXVIII, Part II,
1 RED SINDHI HERD AT THE LIVESTOCK RESEARCH STATION HOSUR
1.1—FARM AND THE STOCK
The Livestock Research Station, Hosur, is located in Mattigiri village in Salem
District and is about 3 miles from Hosur town and about 27 miles from Bangalore
City. It is situated at an elevation of about 3,000 feet above sea level and at the
latitude of 11°N. The average annual rainfall in the region is about 32 inches,
roughly two-thirds of which is received during the monsoon period from August,
to November. The balance is distributed mainly during the summer months of
May, June and July, the period from December to April being practically dry.
The Red Sindhi herd at this farm was started with a foundation stock of 40
cows and four bulls purchased mostly from the home tract of the breed in Sind
(W. Pakistan) during the period 1921-28. A stock of 85 cows was later purchased
during the years 1944-48 but the entire stock with all the progeny except a single
female was sold away soon after purchase. The records of these animals have been
omitted in the present study. The only other addition to the herd came from
the purchase of five bulls, three from the Indian (now National) Dairy Research
Institute Farm at Bangalore and two from Karachi during 1934-42.
The herd has progressively grown in strength as may be seen from Table I.
TABLE I
Average strength of adult stock
(Sindhi herd at Hosur)
Period
1921-30
1931-35
1936-40
1941-45
1946-52
Cows
40
47
65
80
117
Breeding bulls
3
8
6
7
7
In Table I and subsequently in the paper the term 'cows' and 'breeding bulls'
are used to denote animals which have calved or served at least once. It may be
seen from Table I that the increase in strength was particularly marked in the last
two periods.
The farm-bred cows, with at least one completed lactation record each, numbered
305 in all upto March, 1952. They belong to six generations : 50 to the first (i. e.
the group of daughters of foundation cows), 73 to the second, 80 to the third, 69
to the fourth, 29 to the fifth and 4 to the sixth. These and 38 out of the 40 founda-
tion cows provided in all nearly 1,200 lactation records for the present study.
June, 1958] V. N. AMBLE, K. S. KRISHNAN AND J. S. SRIVASTAVA 35
The herd was served by as many as 52 Sindhi bulls. Of these, nine were brought
from outside and four were the sons of foundation cows sired by outside bulls.
The remaining 39 were farm-bred bulls. Fifteen out of the 52 bulls did not have
any daughter with lactation records. Amongst the remaining 37 bulls only 16 had
six or more daughters with records. The daughters of these bulls accounted for
about 80 per cent of the total farm-bred cows with records.
In all 1,450 calves were born in the herd, of which 724 were females. The sex
ratio thus worked out to 1 : 1. Of the female calves born up to 1948 only 54 per
cent completed their first lactation on the farm. Of the others one-fifth died and
the rest were culled.
1.2—FEEDING, MANAGEMENT AND HEALTH
The scales of feeding, it is understood, mostly approximated to Morrisonis
standards. Green feeds were Guinea and Rhodes grasses, jowar or maize silage
and lucerne, mostly raised from irrigated lands on the farm. Salt, lime and mine-
ral supplements were fed to all cattle along with concentrates. Salt was also
provided, otherwise, as a lick.
As regards management, there have been many changes in the administrative
set up of the farm from the time of its inception in 1924 ; but detailed information
on the changes in the schedules of feeding and practices followed regarding rearing
of animals was not available.
Calves in this farm are not weaned at birth but allowed to suckle their dams.
One day in a week complete stripping is done and the yield on that day is taken as
indicating the potential level of production of the cow during the week. The lacta-
tion yield is estimated from these records.
The health of cattle on the farm was looked after by a veterinary dispensary
located in the farm. Out of 724 female and 726 male calves born during the 25
years of study 60 females and 39 males died within a year of birth. Of these
calves which succumbed, 14 females and nine males died within a week from
birth. Six purchased cows out of 40, 18 farm-bred cows out of 305, nine heifers
out of 637 and 19 bull calves above one year of age out of 686 died during the
period of study.
Taking into account the changes in the size of the herd, the annual rate of
mortality for the female calves worked out to about 22 per cent for the period
prior to 1930, about 14 per cent for the period 1931-40 and less than 7 per cent
since 1941. This may be taken as indicating that there was a progressive improve-
ment in the condition of health prevailing in the herd.
1.3—BREEDING POLICY
The improvement of farm animals in respect of their genetic make up depends
on the policy followed in respect of the selection of animals to be bred and of the
system adopted for mating them. No strict policy, to be followed in relation to
either of this, was laid down specifically for the herd during the period under
study. Broadly speaking, animals considered to be too old for breeding or those
36
STATISTICAL STUDIES ON BREEDING DATA [Vol. XXVIII, Part II,
suffering from serious diseases were removed from the herd. Whenever the adult
female stock which included all cows and heifers above one year in age according
to the classification adopted in this farm, was considered surplus to requirements
the animals rated to be inferior by the management were disposed of by sale.
Reasons for disposal were not, generally speaking, explicitly recorded. Bulls and bull
calves not required for farm use were supplied to other Government farms, public
institutions and private breeders. The surplus stock of bulls not sold was castrated.
The quantitative aspects of the selection practised are discussed in the following
sections.
1.3.1—Selection of female stock
Out of 724 female calves born, only 27 were culled before one year
of age and these were sold along with their dams. As has been mentioned earlier,
60 female calves died within a year of birth and 637 entered the young stock
above one year. Seventy five of these (about 12 per cent) were culled before
their first calving. In the case of eleven heifers the culling was due to attack of
disease. Twenty one others were disposed of as they failed to conceive after repeat-
ed services by different bulls. Reasons for the culling of the remaining 43
were not available.
TABLE II
Distribution of the farm-bred cows in the Sindhi herd at Hosur 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
16
23
30
29
25
18
8
10
16
8
7
10
Percentage
culled
8.0
11.5
15.0
14.5
12.5
9.0
4.0
5.0
8.0
4.0
3.5
5.0
June, 1958] V. N. AMBLE, K. S. KRISHNAN AND J. S. SRIVASTAVA 37
TABLE III
Distribution of culled cows in the Sindhi herd at Hosur
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
24
39
39
34
13
14
18
10
9
Percentage
12.0
19.5
19.5
17.0
6.5
7.0
9.0
5.0
4.5
Average age
at culling
Years—Months
3
4
5
7
6
6
7
10
9
4
11
0
11
1
13
0
14
0
Age at culling of the farm-bred adult cows was examined by preparing of a fre-
quency distribution of the 200 cows which were culled (Table II). It was observed
that 50 per cent were culled before seven years of age and about 20 per cent
were retained beyond eleven years. The average age at culling was about seven
years and nine months.
An examination of the distribution of cows according to the number of com
pleted lactations (Table III) indicated that a little over 50 per cent of the cows
were culled before the completion of the third lactation. About 20 per cent of
cows were retained for at least six lactations. Only one out of ten cows was re-
tained for seven or more lactations.
A measure of the intensity of selection practised on the cows from lactation to
lactation is provided by the phenotypic selection differential obtained as the excess
of the average yield weighted by the number of lactations completed by a cow
over the average yield giving equal weights to all the cows. The phenotypic selec-
tion differential of the average yield per lactation per cow worked out to 217 lb.
which is 5.9 per cent of the unweighted average of 3,684 lb. For obtaining these
estimates the average yield per lactation of each cow was worked out by converting
the yields in the later lactations to the first lactation basis by using lactation correc-
tion factors derived in section 4.3.1. The records of cows in the foundation stock
and in the current herd were omitted from consideration.
38
STATISTICAL STUDIES ON BREEDING DATA [Vol, XXVIII, Part II,
1.3.2—Selection of male stock
Thirty nine farm-bred bulls used for service in the farm were selected from a
lot of about 500 male calves born on the farm prior to the year 1948. The selection
percentage thus worked out to about eight. The selection of breeding bulls for
farm use was based on body conformation and the yield of dams.
The extent to which different bulls were used varied considerably. The number
of progeny born to a bull ranged from 2 to 218 with an average of 45. The pheno-
typic selection differential for bulls, based on their dams' performance, was worked
out as the excess of the weighted average of the dams' yield—the weight used being
the number of progeny born to the bull—over the simple average of the cows,
yields. The selection differential due to the choice of bulls and their differential
use was found to be 2,275 lb. or 62 per cent of the average per lactation.
1.3.3—Mating system
Mating of bulls to closely related cows was generally avoided though a small
degree of inbreeding was noticeable in the second and later generations. The per-
centage of inbred cows to the total increased from 37 in the second generation to
89 in the fifth. All the eight cows belonging to the sixth generation were inbred.
The average value of the coefficient for inbred cows was, however, small, the highest
being only 0.08 for the second generation. The position is summarised in Table IV.
TABLE IV
Degree of inbreeding in different generations of the Sindhi cows at Hosur
Generation
Second
Third
Fourth
Fifth
Sixth
Total
number
of cows
84
88
87
36
8
Inbred cows.
Number
31
48
66
32
8
Percentage
37
54
76
89
100
Average
inbreeding
coefficient
0.080
0.042
0.044
0.056
0.052
1.3.4—Breeding performance
The breeding regularity of the herd was examined by working out the average
age at first calving and the average calving interval for the cows. The age at first
calving in the herd varied between two and a half years to five years except in four
cases of calvings after five years, the highest being about eight years. The average
age at first calving based on 350 cows worked out to 41.7 ±0.4 months which
40
STATISTICAL STUDIES ON BREEDING DATA [Vol. XXVIII , Part II,
TABLE V
Average first lactation performance of Sindhi cows at Hosur
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.
Fifth generation—
No. of records
Average
S. E.
C.V.
Overall farm-bred generationsi(a)—
No. of records
Average
S.E.
C.V.
Lactation
yield
(lb).
38
3,052
218
44
46
3,345
224
45
67
3,973
194
40
78
3,768
141
33
66
3,475
181
42
29
3,664
326
48
290
3666
87
40
Yield/day
of
lactation
(lb).
38
9.50
0.49
31
46
10.47
0.44
28
67
11.67
0.42
29
78
11.47
0.35
27
66
11.20
0.41
30
29
11.39
0.79
37
290
11.28
0.19
30
Yield/day of
calving
interval
(lb.)
37
5.54
0.32
36
46
6.38
0.38
41
56
7.49
0.44
44
68
7.36
0.33
37
61
7.00
0.45
50
26
6.84
0.74
55
261
7.07
0.19
44
Lactation
period
(days)
88
304
12
24
46
303
14
31
67
335
9
22
78
324
7
20
66
304
11
29
29
308
17
30
290
317
5
26
Calving
interval
(days)
37
456
21
28
46
519
19
25
56
574
26
34
68
557
18
27
61
534
25
37
26
545
21
38
261
546
10
30
Age at first
calving
(months)
..
..
..
..
52
40.3
0.8
12
83
40.3
0.7
14
89
42.6
0.8
17
86
42.3
0.7
14
86
42.4
0.9
12
350
41.7
0.4
15
(a) This includes four cows belonging to the sixth generation,
June, 1958] V. N. AMBLE, K. S. KRISHNAN AND J. S. SRIVASTAVA 41
The average values for the different characteristics along with the standard
errors and coefficient of variation for cows belonging to the foundation stock and the
different farm-bred generations are given in Table V. The following conclusions
may be drawn from the results :
(i) Farm-bred cows were on the whole significantly superior to the foundation
stock, exceeding them on an average by about 600 lb. of lactation yield, 1.8 lb. per
day of lactation and 1.5 lb. per day of calving interval. There was, however, an
increase in the calving interval of the farm-bred cows to about 18 months from
about 15 months for the foundation cows.
(ii) The first generation cows produced on an average about 300 lb. more milk in
the first lactation than the foundation ones ; increases of about one lb. per day of
lactation and 0.8 lb. per day of calving interval were also observed. None of these
increases was, however, significant. The calving interval for the first-generation
cows was significantly higher than that for the foundation cows by about two months.
(iii) A comparison of the average lactation yield of the second-generation cows
over that of the first-generation cows indicated a significant increase of about 630 lb.
Increases of 1.2 lb. of milk per day of lactation, 1.1 lb. per day of calving interval,
one month in lactation period and two months in calving interval were also observed,
though these just failed to be significant.
(iv) The age at first calving increased from 40.8 months in the second generation
to 42.6 months in the third generation. Changes in respect of other characters
were not substantial.
(v) A fall of about 300 lb. in the average lactation yield was observed from the
third to the fourth generation. This change was, however, not significant.
(vi) There was no material change in respect of any of the characters from the
fourth to the fifth generation. The observations were too few for the sixth generation
to draw any conclusion.
1.4.2—Daughter-dam comparisons
An overall comparison between generations reflects the effects of culling of
female calves before they complete a lactation and of other causes such as sire selec-
tion, system of mating, etc. apart from the non-genetic causes. A comparison of
the average performance of the cows belonging to a generation with that of their
dams will indicate the changes brought about due to reasons other than the culling
of calves. The results of these comparisons are discussed in the following paragraphs.
In order to eliminate the variation due to the order of lactation and unequal
number of records available for the dams and the daughters, comparisons were made
over like lactations by calculating for each daughter-dam pair the averages over all
the like lactations for which records were available. In the case of the comparison
of the first generation of farm-bred cows with their purchased dams the order of
lactation of the latter had to be approximately fixed as has been described earlier.
1 AR/58
2
42
STATISTICAL STUDIES ON BREEDING DATA [Vol. XXVIII, Part II,
TABLE VI
Comparisons of cows belonging to different generations with their dams
(Sindhi herd at Hosur)
Generation
F1
F 2
F 3
F4
F 5
Generation
F 1
F 2
F 3
F 4
F 5
Lactation yield (lb.)
No. of
pairs
33
70
77
68
28
M
3334
3847
4309
3792
4073
D-M
562@
157
—370@
—185
—602@
S.E.
289
216
189
204
322
Lactation period (days)
No. of
pairs
33
70
77
68
28
M
288
314
331
321
334
D-M
13
6
—12
—18@
—43*
S.E.
12
10
8
10
16
Yield./day of lactation (lb.)
No. of
pairs
33
70
77
68
28
M
11.17
10.07
12.01
11.75
12.00
D-M
1.77*
0.31
—0.80*
0.02
—0.50
S.E.
0.66
0.48
0.47
0.50
0.80
Calving interval (days)
No. of
pairs
30
58
64
60
25
M
455
506
517
523
577
D-M
46@
48@
47*
—7
—64
S.E.
25
26
22
25
50
Yield/day of calving interval (lb.)
No. of
pairs
30
58
64
60
25
M
7.32
7.60
8.66@
7.98
7.64
D-M
0.84
0.34
—0.86
—0.48
—0.90
S.E.
0.56
0.47
0.45
0.46
0.73
Age at first calving (months)
No. of
pairs
—
70
77
68
28
M
—
40.0
40.2
41.3
42.0
D-M
—
1.2
2.5*
1.3
0.3
S.E.
—
1.6
1.2
1.1
1.4
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).
*, ** and @ denote the significance at 1 per cent, 5 per cent and 10 per cent respectively in this and later tables.
44
STATISTICAL STUDIES ON BREEDING DATA [Vol. XXVIII, Part II,
of these records over different generations it was considered that their omission
would not introduce any bias but would on the other hand increase the precision of
comparisons among generations.
The results of the appropriate statistical analysis are presented in Table VII.
TABLE VII
Adjusted analysis of variance for periods and generations of Sindhi cows at Hosur
(First lactation yield in units of 10 lb.)
Source of variation
Between periods (adjusted)
Between generations
„
Interaction
Within
generations
within periods.
D.F.
4
4
9
239
H.S.
91,113
20,194
14,191
19,178
V.R.
4.80*
1.05
(not significant)
It will be seen from Table VII that the interaction between generations and periods
was not significant. The variation between periods making due allowance for
generation differences was significant while the variation between generations
adjusted for period was not significant. The adjusted averages for the different
periods and generations are given in Table VIII.
TABLE VIII
Adjusted period and generation averages for first lactation yields of Sindhi cows at Hosur
Period
1924-30
1931-35
1936-40
1941-45
1946-51
Number
of records
9
47
65
55
81
Adjusted
average
(lb.)
2062
3627
4222
3537
3772
Order of
generation
F1
F 2
F3
F 4
F5
Number of
cows
40
60
69
61
27
Adjusted
average
(lb.)
3875
3981
3716
3431
3886
The results in Table VIII indicate that a low performance during the period
1924-30, an improvement from 1930 to 1940 and again a fall during 1941-45
account for the significant variation observed from period to period.
June, 1958] V. D. AMBLE, K. S. KRISHNAN AND J. S. SRIVASTAVA 45
1.4.4—Overall Conclusions
The trends observed in the performance of cows belonging to different generations
in the course of the analysis given in the above sections may be briefly summarised
as follows :
(a) The overall changes in the three milk characters, viz., lactation yield, yield
per day of lactation, and yield per day of calving interval were almost parallel.
There was an increase in the average yield both from the foundation stock to
the first generation, and from the first generation to the second [Table V]. There
were no material changes in the later generations.
(b) The improvement brought about in the first and the second generations
appeared to be mainly through better management and changes in other environ-
mental factors from 1930 to 1940.
(c) The average lactation period was generally over 300 days in all the genera-
tions and this should be considered as a satisfactory feature about this herd.
(d) The average age at first calving was about 40.5 months for cows in the first
and the second generations. For the later generations it was about two months
more.
(e) The average calving interval for the farm-bred cows was as high as about
18 months while for the foundation cows it was about 15 months.
1.5—TRANSMITTING ABILITY OF BULLS
Sire selection is of vital importance in any scientific breeding programme for
cattle improvement. This is due to the greater impact of the choice of the sire on
the genetic make-up of the future herd in virtue of the very large number of progeny
that can be produced by a sire as compared to a cow.
Of the different methods available for selecting an animal, viz., the performance
test, the pedigree test, and the progeny test, the first one is ruled out for sire selection
in a dairy herd as milk yield is a sex-limited character. The pedigree test can
provide only limited information and this may be used for a preliminary choice.
Progeny test alone provides a satisfactory method for assessing the breeding worth
of a sire.
1.5.1—Progeny testing
The changes brought about by a bull in. the average production level of the herd
on which it was used can be assessed by the progeny performance test. This consists
in comparing the average production level of the daughters of the bull with that of
their dams. It is desirable to make such comparisons over like lactation records
of the daughters and their corresponding dams in order to obviate possible bias due
to lactation differences. The precision of the test can be increased by taking as
the variate the mean difference per lactation over all available like lactations for
each daughter-dam pair. Each bull may be tested by examining the significance
46
STATISTICAL STUDIES ON BREEDING DATA [Vol. XXVIII, Part II,
TABLE IX
Progeny testing of Sindhi bulls at Hosur
Serial No.
1
1
2
3
4
5
6
7
8
10
11
12
13
14
15
16
Bull No.
2
56
129(0)
8
118(0)
238
136(0)
139
38
43(0)
236
98
124(0)
65
282
144
255
Daughter
dam
pairs
3
9
7
28
6
8
7
12
21
10
19
10
11
12
14
23
27
Lactation yield (lb.)
Average
for
dams
4
4253
3877
3709
3368
4333
3508
4924
3988
2995
3920
4625
3578
4022
4126
4087
4076
Daughter
dam
difference
5
1312
602
413
919*
—41
897
—530
—98
882*
25
—315
—46
—748
—765
—772@
—908**
S.E.
6
811
785
292
273
456
488
342
222
332
485
570
467
437
454
432
286
Yld./day of lactation (lb.)
Average
for
dams
7
13.48
12.47
11.72
11.05
12.94
10.99
14.80
12.18
11.32
11.55
13.97
11.40
12.02
11.68
12.14
12.56
Daughter
dam
difference
8
2.68
0.46
0.93
3.55@
0.67
2.03
—2.12@
—0.32
1.40
1.09
—0.51
—0.10
—1.74
—0.14
—0.57
—1.64*
S.E.
9
1.98
1.16
0.72
1.52
1.73
1.10
1.07
0.57
1.07
0.93
1.33
1.10
1.21
1.09
1.07
0.79
Yld./day of calving interval (lb.)
Average
for
dams
10
9.88
8.30
7.63
7.83
9.13
7.47
10.67
8.24
6.92
8.15
9.61
6.82
7.51
6.57
7.52
8.21
Daughter
dam
difference
11
2.56
—0.40
0.66
0.17
—2.10
1.53
—1.48@
—1.49**
1.40
0.08
—0.89
1.31
—1.02
—0.03
—1.17
—1.52@
S.E.
12
1.85
1.16
0.74
0.98
1.24
0.85
0.79
0.50
0.77
0.75
1.13
0.99
0.98
1'16
0.84
0.79
Lactation period (days)
Average
for
dams 13
317
311
312
303
333
323
332
328
260
333
329
304
335
342
335
323
Daughter
dam
difference 14
18
32
13
—2
—12
16
15
3
48@
—36
—5
9
—9
—53**
—60**
—37*
S.E.
15
23
33
14
29
24
18
13
13
24
26
12
16
21
16
20
14
48
STATISTICAL STUDIES ON BREEDING DATA [Vol. XXVIII, Part II,
TABLE X
Sire indices of Sindhi bulls at Hosur
Serial No.
1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Bull No.
2
56
129 (0)
8
118 (0)
238
136 (0)
139
38
43 (0)
236
98
124 (0)
65
282
144
255
Daughter
dam
pairs
3
9
7
25
6
7
6
11
17
10
18
10
11
12
11
23
27
Herd average to which indices
correspond.
Lactation yield (lb.)
Average
for
dams
4
4298
3877
3651
3368
4646
2998
4827
3664
2995
3860
4499
3364
4029
4320
4118
4019
Corrected
daughter average
Index
5
4976
4448
4372
4346
4301
4288
4060
4029
4002
3895
3670
3343
3203
3167
3117
2917
S. E.
6
841
532
258
575
451
317
303
212
449
477
310
481
282
490
323
236
3700
Yield/day of lactation (lb.)
Average
for
dams
7
12.87
12.47
10.99
11.05
13.15
9.17
14.15
10.48
11.32
11.01
12.78
10.83
11.22
11.46
12.13
12.28
Corrected
daughter average
Index
8
14.07
12.83
12.67
14.64
12.72
11.95
11.54
11.74
12.74
12.30
11.67
10.26
9.37
11.30
10.31
10.57
S. E
9
1.03
1.23
0.65
1.33
1.17
1.35
1.02
0.75
1.03
0.80
0.94
1.10
1.04
0.87
0.68
0.63
11.5
Yield/day of calving interval
(lb.)
Average
for
dams
10
7.90
8.30
7.58
7.83
9.36
6.32
10.12
7.29
6.92
7.24
9.32
6.70
6.69
7.01
7.37
8.22
Corrected
daughter average
Index
11
8.93
7.77
8.30
7.92
5.95
8.45
7.20
6.69
8.33
8.20
7.96
8.22
6.39
6.62
5.25
6.24
S. E.
12
1.00
1.14
0.65
1.23
1.13
1.34
1.06
0.75
0.95
0.75
1.05
1.06
1.03
0.87
0.69
0.63
7
Lactation period (days)
Average
for
dams
13
334
311
325
303
343
330
339
348
260
346
351
306
359
357
337
326
Corrected
daughter average
Index
14
345
346
344
301
321
354
360
342
309
300
323
351
346
280
296
273
S.E.
15
24
28
15
31
27
31
23
18
24
19
23
25
24
21
16
15
300