NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
SEPTEMBER, 1948]
JOHN
B.
POLDING
165
TABLE XLII.
Short term count of the survival of Brucella in saline vehicle
Time in hours
0
4
8
12
24
51½
65
Count in million per c.c.
2900
4400
4500
5400
1650
104
68
Culture = Cotton's 19, 48 hours old.
Browns' scale = 5-6.
Medium = Tryptose.
Vehicle = 0.85 per cent saline.
Technique = Standard.
Storoge = 42°C.
The effect of alterations in the pH of the vehicle was first studied and in two experiments [Ex-
periments I and II, Figs. 4 and 5 ] it was shown that Brucella vaccines suspended in 0.85 per cent
NaCl, buffered with M/50 Sorensen's phosphates, and stored at 42°C., tolerated the acid range pH 6.0
to 6.8— but were intolerant of the extremes—pH 5.4 or pH 8.0. Moreover, during both experiment
it was found that, although buffered, the reactions of the substrates drifted towards alkalinity. This
was first observed in Experiment I and it was thought to be due, perhaps, to an adulteration of the
suspension with substances derived from the agar. In Experiment II, therefore, this possibility was
avoided by washing the bacteria in a single change of vehicle, but although minimized the tendency
was again noted. To lessen the effect of this drift, an optimum pH of about 6.4 to 6.6 was selected
and used in all experiments subsequent to Experiment III.
In Experiment III, Fig. 6 the effect of the presence of inorganic salts was examined and it
appeared that survival in buffered distilled water was not so good as in buffered physiological saline
while a complex salt solution was no improvement on the sample.
Experiment IV was designed to show the effect of the addition of small quantities tryptose,
gelatin or glycerine to the optimum buffer evolved in the foregoing tests. The records, Fig. 7
suggest that, not only did the most regular death-rate occur in the tryptose solution, but here also
the total survival was to a small degree the best, gelatin proving a good second.
The close of the scheme curtailed any further attempt to improve the keeping qualities of the
vaccine, and so the survival rate in the ' improved ' vehicle was compared with that in common saline.
The storage temperatures selected were 42°, 30° and 0.0C. and the solutions were counted over a period
of a few weeks. The respective merits of the optimum and saline substrates may be judged from
an inspection of Fig. 8 and four major points seem to emerge from this work viz., (1) during five
or six weeks storage at 0°C., the death-rate in either vehicle is trivial. (2) at Indian plains tempera-
tures (i.e., 70 to 110°F.) the viable count falls rapidily in relation to the time and temperature of
storage. (3) In moderate temperatures at least, it seems probable that an initial phase of mortality
is followed, in three or four weeks, by one of multiplication. (4) At the lower temperatures, the opti-
mum vehicle gains some initial advantage over the common saline, a lead which is held but not
increased, thereafter. At 42°C. the optimum vehicle appears to have a decided advantage over the
saline.
G 2
166
Contagious Abortion of Cattle, Sheep and Goats [VOL. XVIII, PART III,
FIG. 4. *The effect of pH of the vehicle on the keeping qualities of Brucella vaccines.
A=pH 6.0
B=pH 7.0
C=pH 8.0
Conditions of experiment in fig. 4.
Vehicle. Glass distilled water containing NaCl (pure) 0.85 per cent and buffered with Sorensons
phosphates M/50 to the pH shown.
Storage. The temperature of storage was 42° C.
Suspension. The suspension was made from a 48 hours old, culture of Cotton's strain 19, its
density was 5 on the Browns scale.
Table of bacterial counts in hundreds of millions per c.c.
Hours
0
.
.
.
.
.
.
.
.
.
.
.
16
.
.
.
.
.
.
.
.
.
.
.
20
.
.
.
.
.
.
.
.
.
.
.
24
.
.
.
.
.
.
.
.
.
.
.
30
.
.
.
.
.
.
.
.
.
.
.
40
.
.
.
.
.
.
.
.
.
.
.
48
.
.
.
.
.
.
.
.
.
.
.
pH 6.0
117
130
140
98
95
109
70
pH 7.0
90
100
69
79
67
29
19
pH 8.0
93
64
46
27
18
1.1
1.5
SEPTEMBER, 1948]
JOHN
B.
POLDING
167
FIG. 5. *The effect of pH continued.
A=pH 5.4
B=pH 6.0
C=pH 6.8
* For conditions and table of counts see overleaf.
170
Contagious Abortion of Cattle, Sheep and Goats [VOL. XVIII, PART III,
FIG. 6. * The death-rate of Brucella in variously composed substrates.
A. in distilled water
B. in 0.85 per cent pure NaCl
C. in complex saline
All substances were buffered with Sorensen's M/50 phosphates to pH 6.0.
Experimental conditions in fig. 6
Vehicle. Glass distilled water was used in all cases. The composition of the complex saline
used in C. was as follows:
NaCl 0.9 per cent
CaCl 2 0.024 per cent
KCl 0.042 per cent
NaHCo 3 0.01 per cent
MgCl 2 0.1 per cent
*For further details and table of bacterial counts see page 171
SEPTEMBER, 1948]
JOHN
B.
POLDING
171
Storage. The temperature of storage was 42° C.
Suspension. The suspension was prepared from a 48 hours old culture of Cotton's strain 19,
washed once by centrifugation and resuspension. Its density was 5 on the Brown's scale,
Note. The pH of the substrate drifted during the test as follows:
Test A. pH 6.0 to 6.2
B. pH 6.0 to 6.2
C. pH 6.0 to 6.4.
Table of bacterial counts in hundreds of millions per cc.
Hours
0
.
.
.
.
.
.
.
.
.
20
.
.
.
.
.
.
.
.
.
26
.
.
.
.
.
.
.
.
.
32 . . . . . . . . .
44 . . . . . . . . .
56
.
.
.
.
.
.
.
.
.
68 . . . . . . . . .
92 . . . . . . . . .
Distilled H 2 O
117
55
30
14
1.25
0.14
0.02
0.0
Saline
118
66
60
35
14
1.9
0.6
0.08
Complex saline
110
70
68
29
6
1.14
0.34
0.06
H
172
Contagious Abortion of Cattle, Sheep and Goats [VOL. XVIII, PART III,
FIG. 7. The death-rate of Brucella in variously composed substrates:
A. Pure NaCL 0.85 per cent buffered pH 6.4
B. Pure NaCL 0.85 per cent buffered pH 6.4 plus 0.1 per cent tryptose.
C. Pure NaCL 0.85 per cent buffered pH 6.4 plus 0.1 per cent gelatin
D. Pure NaCL 0.85 per cent buffered pH 6.4 plus 0.1 per cent glycerine
Experimental details of fig. 7
Suspension. The suspension was prepared from a 48 hours culture of Cotton's strain 19 at
density 5 on Brown's scale. It was washed once by centrifugation and resuspension.
Storage. At 42°C.
Table of bacterial counts in hundreds of millions per cc.
Hours
0
.
.
.
.
.
.
.
.
.
.
20
.
.
.
.
.
.
.
.
.
.
26 . . . . . . . . . .
32 . . . . . . . . . .
44 . . . . . . . . . .
56 . . . . . . . . . .
68
.
.
.
.
.
.
.
.
.
.
Test A
120
81
70
44
42
6.3
0.19
Test B
94
92
68
50
25
10.4
2.1
Test C
106
157
68
65
35
9.7
0.97
Test D
75
81
44
55
26
7.0
0.93
SEPTEMBER, 1948]
JOHN
B.
POLDING
173
FIG. 8.* The keeping qualities of Brucella at three different temperatures of storage and in a simple and an improved
substrate:
A. Simple Saline substrate
B. Improved substrate
1. Storage at 42°C
2. Storage at 30°C
3. Storage at 0°C
Details of experiment in fig. 8
Suspension. The suspension was prepared from a 48 hours old culture of Cotton's strain 19, at
density 5 on the Brown's scale.
Substrate. The simple substrate consisted of 0.85 per cent common salt in distilled water. The
improved vehicle was made up as follows.
NaCl pure 0.85 per cent
Tryptose 0.1 per cent in glass distilled water buffered with Sorensen's phosphates
M/50 to pH 6.6.
* For table of bacterial counts see overleaf.
H 2
174
Contagious Abortion of Cattle, Sheep and Goats
[VOL. XVIII, PART III,
Bacterial counts in hundreds of millions per cc.
Days
0 . . . . . .
3
.
.
.
.
.
.
5
.
.
.
.
.
.
7
.
.
.
.
.
.
10 . . . . . .
11
.
.
.
.
.
.
15 . . . . . .
16
.
.
.
.
.
.
21 . . . . . .
26 . . . . . .
38 . . . . . .
A1
63
0.29
..
..
..
..
..
.
..
..
..
B1
38
3.6
..
0.14
..
0.06
..
0.009
..
..
..
A2
103
..
68
..
14
3.5
..
0.2
0.23
0.7
B2
104
..
109
..
64
..
8
..
0.63
0.93
1.44
A3
103
..
93
..
101
..
91
..
8.9
24.3
37
B3
104
..
104
..
149
..
123
..
16.4
32.4
117
SEPTEMBER, 1948]
JOHN
B.
POLDING
175
FIG. 9. *The death-rate of Brucella in various environments
A. Stationary at 42°C
B. At changing temperature
C. Shaken at room temperature during the day
*For details and table of bacterial counts see overleaf.
176
Contagious Abortion of Cattle, Sheep and Goats
[VOL. XVIII, PART III,
Experimental details of Fig. 9
Suspension. Prepared from a 48 hours old culture of Cotton 's strain 19, at a density of 5 on
the Brown's scale.
Substrate. Glass distilled water containing 0.85 per cent. pure NaCl and 0.1 per cent. tryptose,
buffered with Sorensen's phosphate M/50 to pH 6.4.
Storage. Test A. (Control) stationary at 42° C.
Test B. 10 a.m. to 12 noon at 37° C.
12 noon to 4 p.m. at 42° C.
4 p.m. to 8 p.m. at 30° C.
8 p.m. to 8 a.m. at 0° C.
Test C. Shaken at room temperature from 10 a.m. to 4.30 p.m. and stationary at 42° C
during the night.
Table of bacterial counts in hundreds of millons per cc.
Hours
0 . . . . . . . .
12 . . . . . . . .
24 . . . . . . . .
30 . . . . . . . .
60
.
.
.
.
.
.
.
.
72
.
.
.
.
.
.
.
.
Test A
88
121
94
77
51
15.9
Test B
88
131
113
110
91
..
Teat C
88
84
87
77
26
18.5
SEPTEMBER,
1948]
JHON
B.
POLDING
177
FIG. 10. The death-rate of Brucella in different environments.
Experimental details of fig. 10
Suspension, Prepared from a. 48 hours old culture of Cotton's strain 19, at density 5 on the
Brown's scale.
Substrates. In tests A, B and D 0.85 per cent common saline.
In test C as in fig. 9.
Storage. Test A (control) stationary at 42° C.
Tests B and C shaken, and in Test D jerked at room temperature from 10 a.m. to 10 p.m. and
stationary during the night at 42° C.
Table of bacterial counts in hundreds of millions per cc
Hours.
0 . . . . . . . .
12 . . . . . . . .
24 . . . . . . . .
36 . . . . . . . .
48 . . . . . . . .
Test A
39
23
6.3
0.59
0.11
Test B
39
42
..
26
6.9
Test C
22
28
39
25
17
Test D
39
33
37
..
1.8
178
Contagious Abortion of Cattle, Sheep and Goats
[VOL. XVIII, PART III,
FIG. 11. *The death-rate of Brucella in different environments, etc.
Test A. Unshaken at room temperature (control) common saline
Test B. Shaken at room temperature, common saline substrate
Test C. Shaken at room temperature, improved substrate
*For details and table of bacterial counts see page 181.
SEPTEMBER, 1948]
JOHN
B.
POLDING
179
FIG. 12.
1
180
Contagious Abortion of Cattle, Sheep and Goats
[VOL. XVIII, PART III
FIG.
13.
SEPTEMBER, 1948]
JOHN
B.
POLDING
181
Experimental details of fig. 11
Suspension. Prepared from a 48 hours old culture of Cotton's strain 19, at a density of 5 on
the Brown's scale.
Substrate. Tests A and B. 0.85 per cent common salt in distilled water.
Test C. as in fig. 9.
Storage. Test A. At bench temperature, unshaken.
Test B. Shaken at bench temperature.
Test C. Shaken at bench temperature.
Table of bacterial counts in hundreds of millions per cc.
Hours
0
24
36
48
60
72
Test A
58
..
95
..
70
57
Test B
58
79
55
47
13
4.8
Test C
60
79
30
29
13.4
7.2
cannot be omitted, but the owner should be fully informed of the position. There remain two other
groups of possible vaccinees, viz., heifers, which become eligible for inoculation at any time during
the six months preceding the anticipated age of first oestrus, and calves between 4 to 8 months of
age. It is for decision which of the classes, both now, and in the future are going to be most convenient
to vaccinate and, in deciding this, the following points should be borne in mind : (1) that calves are
more easily handled than heifers—with wild stock an important point ; (2) that, on the whole, a better
immunity can be hoped for in heifers and (3) that if the decision is to vaccinate calves, then the
existing heifers and all young stock over eight months must be protected. This must be done by
vaccinating heifers until the first batch of calves vaccinated at 4-8 months are coming through.
Other minor points, such as ease of access to and manipulation of future batches of vaccinees are also
worthy of consideration. Having settled on one or other group of on-coming young stock, they
should be vaccinated in batches, as they accumulate, either quarterly or half-yearly.
It is difficult to advise on the period for which vaccination should be continued, but, in deciding
on its discontinuance, factors affecting the introduction and transmission of new disease (p.131) should
be duly weighed, abortions should be less than 1 per cent per annum and, if a non-agglutinin-producing
vaccine has been used, the adult stock should be tested and found negative before control measures
are withdrawn.
Difficult types of farms to deal with are either military farms, where of necessity, stock is being
continually interchanged or farms, where replacement animals are purchased. In the former, a
universal routine vaccination of young stock and purchases might suffice to avert disease but, in the
latter, attention must be given to the source of purchases, in relation to endemic areas, which should
be barred. Animals should be bought subject to their passing the quick test and afterwards vacci-
nated as quickly as possible.
Field trials of vaccination
Up till now, Brucella vaccine has been used in several south Indian villages, in some four or five
private farms and in five military establishments. As regards villages, not only is it too early to
12
SEPTEMBER, 1948]
JOHN B. POLDING
183
TABLE XLIV
Results of the vaccination of calves and heifers in military farms
Farm
I
II
III
IV
V
VI
Total
Vaccinees age group 4—8 months
Agglutination results
No.
done
26
29
37
28
27
32
179
1st test
+++
24
14
36
20
13
25
132
++
2
5
1
6
8
3
25
±
—
6
—
1
5
3
15
—
—
—
—
1
—
—
1
2nd test
++
11
13
24
12
12
8
80
—
9
10
8
9
13
6
55
Calving
results
Nor-
mal
—
—
—
—
—
—
—
Ab-
nor-
mal
1
—
—
—
—
—
1
Vaccinees age group 18—24 months
Agglutination result
No.
done
27
13
24
48
25
—
137
1st test
+++
26
13
24
44
22
—
129
++
1
—
—
2
3
—
6
±
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
2nd test
19
13
24
36
19
—
111
3
—
—
—
6
—
9
Calving
results
Nor-
mal
16
2
—
—
—
—
18
Ab-
nor-
mal
1*
—
1
—
—
—
2
Calving results of non-vaccinated
controls
Group 4 to 8 months
Calving
No.
kept
27
29
37
27
27
—
178
Nor-
mal
—
—
—
—
—
—
—
Ab-
nor-
mal
1
—
—
—
—
—
1
Group 18 to 24
months
Calvings
No.
kept
25
13
23
48
25
—
134
Nor-
mal
14
—
—
—
—
—
14
Ab-
nor-
mal
1
—
—
—
—
—
1
+++ = Strongly positive
++ = Weakly
„
± = Doubtfully „
— = Nil
* = Stillborn
186
Contagious Abortion of Cattle, Sheep and Goats
[VOL. XVIII, PART III
Both strains were non-pathogenic for mice, guinea-pigs, and rabbits ; thus again differing from
Listerella ; but in pregnant goats one or two pathogenic effects were noted that can hardly be ignored.
They are schematized in Table (XLVI).
TABLE XLVI
The injection of pregnant goats with X strains
Goat No.
380
341
430
456
504
593
332
Inoculum and route
X.39 (5.0 c.c. of a 48 hours broth culture,
intravenously).
X39 (5.0 c.c. of a 48 hrs. broth cultures,
intravenously),
X39 (5.0 c.c. of a 48 hrs. broth culture fil-
trate, intravenously).
X380 (5.0 c.c. of a 48 hrs. broth culture,
intravenously).
X456 (5.0 c.c. of a 48 hrs. broth culture,
intramuscularly).
X456 (5.0 c.c. of a 48 hrs. broth culture,
intravenously).
X31(5.0 c.c. of 48 hrs. broth culture, in-
travenously).
Results
Aborted within 24 hours ; culture of foetal stomach contents
gave X-like strain. Other foetal tissues sterile. Hæmo-
cultures on 8th and 14th day sterile vaginal swabs on
12th, 13th, 14th and loth days gave cultures of X-like
organisms. Strain isolated denoted X380.
None, in two months.
None, in two months.
Died 10th day with symptoms of fever and pneumonia.
Culture made from placenta and foetus yielded a typical
X organism, denoted X 456.
Aborted within 48 hours. Foetal cultures sterile. Died
6 days after injection with enteritis and metritis.
Died five days later with nascent pneumonia. Organism
typical of X strains isolated from placenta. Culture
denoted X 493.
Aborted after 20 days. Foetal culture negative for X types.
Developed purulent metritis. Died 10 days after abor-
tion. No X-type could be isolated.
Out of six pregnant goats receiving viable X strains, only one remained unaffected (No. 341)
while three aborted and four died. From three affected goats an X-like strain was recovered in pure
culture, in each case from the genital tissues. The remarkable and baffling point is that two of the
three abortions occurred within 48 hours of the administration of the injection ; in one case in the
night following and in the other during the second night following inoculation. It is scarcely believ-
able that these early abortions could be the direct result of bacterial invasion, but it is perhaps possible
that this organism is a fairly common inhabitant of the goat and that the injections precipitated a
crisis of an otherwise subclinical infection. In this respect it has already been noted, how little is
required to provoke a goat to abortion. It is perhaps unfortunate that no tissues of the dead goats,
other than genital, were cultured. Pneumonia is fairly common in goats and at that time it was not
associated with the injections. In retrospect, however, it does not seem improbable the X organism
may have been a cause of the pneumonia, and in fact be concerned in goat pneumonia in general. On
190
Contagious Abortion of Cattle, Sheep and Goats
[VOL. XVIII, PART III,
tested four or more times at very irregular intervals averaging about six months apart. Indeed,
the inspection of individual records suggests that few goats were blood-positive for more than two
months at a time. Secondly, the appearance of positive blood reactions in relation to abortions
was very irregular (Table XLVII).
TABLE XLVII
Blood reactions in relation to abortions
Before abortion
—12
1
—9
2
—6
0
—3
0
Months.
0
4
After abortion
+3
2
+6
1
+9
2
+ 12
1
13 Observations.
Figures= numbers of +reactors found at the month shown. Six of the goats reacting at times distant from abortion
were negative to tests occurring nearer to abortion. The remainder were not tested in between.
Thirdly, of 66 goats that aborted between 1929 and 1935, 37 were blood-tested. Of these, 17
were positive, four were doubtful and 16 were negative. Now an inspection of Table XLVIII shows
that amongst these 17 reactors, 12 (70 per cent) required four or more tests for their detection
and, in view, of this, it is fair to assume that some 70 per cent of the 11 negative goats that were
tested not oftner than twice, would be positive if tested four times or oftner. The final picture of the
test results of those 37 aborting goats then, appears as in Table (XLIX).
TABLE XLVIII
The final picture of test results
Positive reaction occurs
Never . . . . . .
Once . . . . . .
Twice . . . . . .
Thrice (or oftner) . . .
6 tests
(or more)
3
4
4
1
5 tests
1
2
0
0
4 tests
1
1
0
0
3 tests
0
1
0
0
2 tests
2
1
0
0
1 test
9
3
0
0
Figures in Table=No. of goats reacting as shown in column I when tested the No. of times shown at column heads.
TABLE XLIX
Number of tests necessary
Reaction
Positive . . . . . . . . . . . . .
Doubtful . . . . . . . . . . . . .
Negative . . . . . . . . . . . . .
Actual
17 to 25
4
16 to 8
Per cent
46 to 65
10
43 to 21
37 Observations.
Further, the probability is that the higher positive figures are correct, suggesting that Brucellosis
caused the majority of abortions.
It must, however, be admitted that many of these goats became positive as late as several months
after abortion and it can be supposed that they were infected during the interval. All that transpires
196
Improvement of Wool Quality by Selective Breeding
[Vol. XVIII, Part IV
noticed that in these breeds, the range of medullation varied from 0 to 100 per cent. On the basis of
medullation of wool, fleeces were divided into the following four classes [Nanda, 19471.
A Class . .
B Class . .
C Class . .
D Class . .
Fine woolly fleeces with 0 to 20 per cent medullation, quite suitable for the
manufacture of clothing material.
Ideal carpet type fleeces with 20 to 40 per cent medullation, best suited for
carpets.
Coarse hairy fleece with 40 to 70 per cent medullation, conforming to in-
ferior type of carpet wool suited for low grade carpets.
Very coarse hairy fleeces with 70 per cent and higher medullation, hardly
suitable for spinning and weaving processes.
Selective breeding and inter-breeding of different classes
The procedure adopted for selective breeding consisted in classifying flocks of Bikaneri and
Lohi ewes into A, B, C and D types according to the standard mentioned above. To start with, only
a small percentage of better type fleeces were available, as the majority of ewes came in C and D classes.
More of A and B type rams were introduced each year and the C and D type ewes were eliminated
in successive years. Shoulder samples of all the male progeny at the lamb's clip and of the female
progeny at the 2nd clip were tested to judge the improvement and to help in selection for future breed-
ing. This practice, exhibited a gradual but distinct improvement in the new progeny with increased
number of A and B type lambs each year. The following figures indicate the results obtained in
Table I.
TABLE I
Bi kaneri sheep—fleck strength—500 breeding ewes
Class of
progeny
tested
Males .
Females
Year during which tested
1943-44 . . .
1944-45 . . .
1945-46 . . .
1946-47 . . .
1943-44 . . .
1944-45 . . .
1945-46 . . .
1946-47 . . .
Total
No. of
rams
used
15
15
15
15
15
15
15
15
No.of
rams with
A & B
fleeces
A
..
2
6
6
..
2
6
6
B
..
1
2
4
..
1
2
4
No. of
progeny
tested
107
165
165
132
109
145
144
177
Percentage of fleeces in different
classes with approximate amount of
medullation
A
0-20
per cent
4.7
6.1
8.2
24.2
7.3
131
14.8
36.7
B
20-40
per cent
10.8
19.4
22.8
31.1
22.0
18.6
17.6
26.5
C
40-70
per cent
35.5
46.6
49.7
38.6
37.5
40.7
40.5
21.3
D
70 per cent
and
higher
49.0
27.9
19.3
6.1
33.2
27.6
27.1
15.6
Lohi sheep—flock strength—200 breeding ewes
Males .
Females
1943-44 . . .
1944-45 . . .
1945-46 . . .
1946-47 . . .
1947-48 . . .
1943-44 . . .
1944-45 . . .
1945-46 . . .
1946-47 . . .
1947-48 . . .
6
6
7
6
6
6
6
7
6
6
..
1
3
4
5
..
1
3
4
5
..
1
1
2
1
..
1
1
2
1
93
82
84
63
94
51
58
74
87
86
11.8
18.2
24.4
31.7
42.5
7.8
12.0
20.2
31.0
38.8
11.8
15.9
15.1
23.8
23.4
13.7
10.3
18.9
24.1
23.6
40.8
31.8
40.7
36.5
34.1
39.2
44.8
35.2
40.2
37.6
35.6
34.
19.
8.0
..
39.2
32.5
25.
4.7
..
December 1948]
P. N.
NANDA
AND
GURBAX
SINGH
197
It is evident from the above Table I that in about 4 to 5 years' time, the percentage of progeny
with finer type of wool increased from 6.0 to 30.4 per cent in the Bikaneri flock and from 9.8 to 40.6 per
cent in Lohi flock with a decrease in the coarse and hairy types from 41.1 to 10.8 per cent and 37.4
per cent to 0 per cent in the two flocks respectively. With continued selection, complete elimination
of C and D types and the establishment of pure A or B type flock is now envisaged. Improvement
would have been quicker if it had been possible to use all A class rams from the very first year. This
was not possible as only a limited number of male lambs upto the required standard were available for
selection in the beginning. The comparatively quicker improvement in the Lohi flock was due to
the larger number of A and B type rams used.
With a view to study the results of inter-breeding among different classes, the inheritance of
medullation in the grading up of C and D type ewes with A and B type rams and the possibility of
evolving a clothing type woolly sheep by inter-crossing of A class sheep, breeding records of different
crosses during the last three to four years have been analyzed. The information, thus obtained,
provides a basis for formulating a general plan for the improvement of fleece quality of Indian sheep.
The results obtained by various crosses are shown in Table II.
TABLE II
Bikaneri sheep
Type of
rams
Unclassed .
A
B
C
Type of ewes crossed
Unclassed
....
A
B
C .....
D .....
Unclassed
.
A
.....
B
C
.....
D
.....
Unclassed
....
A
.....
B
.....
C
D
.....
Unclassed
....
A
B
C
No. of
ewes
bred
209
4
25
49
23
121
26
31
49
25
79
3
12
25
14
72
1
2
5
Percentage of progeny in different clases
A
15.3
25.0
20.0
18.3
12.6
33.9
61.5
51.6
32.6
26.4
8.8
66.6
33.3
16.0
7.1
4.2
..
50.0
..
B
22.5
50.0
36.0
28.5
21.7
31.4
34.6
22.6
44.8
32.3
32.9
..
33.4
48.0
35.7
6.9
..
..
20.0
C
45.4
25.0
32.0
42.8
56.5
25.6
3.9
25.8
20.4
35.3
45.5
33 3
33.3
20.0
35.7
45.8
100.0
50.0
40.0
D
16.8
..
12.0
10.4
9.2
9.1
..
..
2.2
6.0
12.8
..
..
16.0
11.5
43.1
..
..
40.0