218
Brucellosis in Dairy Herds in Bengal
[XVII
Evidently, the infection was introduced along with the imported animals, spread rapidly among
the original (more susceptible) stock and later also among the imported stock. This serves as a
typical example of the dangers to which a previously uninfected herd is exposed when indiscriminate
additions are made.
Among the herds tested, there were two buffalo herds. Like their counterpart cattle herds,
and in keeping with the history of abortions in them, one was found free from infection and in the
other, out of 45 animals tested, there were fourteen positive and three doubtful reactors.
DISCUSSION
It was originally planned to test a large number of herds, but it was soon realized that that
was neither practicable, since some herd owners could not be persuaded to the test, nor necessary,
because in many herds abortions were reported to be either absolutely unknown over long
spans of years or too few and far between to warrant a suspicion of Brucellosis. A majority of the
herds left out was small, well isolated and practically self-contained units, in contrast with many
of the larger herds in which abortions have been occurring frequently and to which indiscriminate
additions have been made from time to time. Thus, while actual testing of a few herds of the former
class has shown them to be free from demonstrable infection, even in the face of a few sporadic abor-
tions, a varying incidence of positive reactions has been encountered in many herds of the latter
class. As expected, the highest percentage of infection was in a pinjrapole herd which is constituted
on lines welcoming all sorts of animals at all times.
TABLE I
Result of agglutination tests
Herd
1
2
3
4
5
6
7
8
Locality
Darjeeling Dist. .
Ditto .
Ditto .
Midnapore . .
Dist. 24-Parganas
Dist. Khulna .
Barisal . .
Dacca . .
Breed
Welsh, Sahiwal and
Jersey
Mixed foreign and
Indian
Ayreshire and Jersey
Mainly Hariana .
Buffalo . . .
Mainly Hariana .
Ditto . .
Hariana . .
Date of
Test
1934-35
1935-36
1936-37
1937-38
1938-39
1936-37
1937-38
1937-38
1941-42
1941-42
1942-43
1942-43
17-4-43
9-5-43
7-9-43
Number
tested
7
99
32
92
67
15
53
13
12
15
3
45
23
22
54
Reactions
Positive
2
50
5
46
35
..
6
1
..
..
2
14
4
1
..
Doubt-
ful
..
2
..
..
..
..
..
..
3
5
1
3
..
..
..
Nega-
tive
5
47
27
46
32
15
47
12
9
10
..
28
19
21
54
History of abortion, etc., and
other remarks
Herd reported free from abor-
tions till 1933.
Figures of
abortions during 1934-1939
are given in text. Enquiry
in 1944 revealed practically
no abortions after 1940.
Herd reported to have remained
generally free from abortions,
but in 1936 four cows aborted
within the space of five
months.
Absolutely no abortions for at
least ten years before test
and since then. The single
reaction was probably non-
specific.
No abortions until mid-May
1940,
when seven cows
aborted within a few months ;
four died soon after abortion.
Malpractice was suspected.
A pinjrapole herd. Abortions
etc. have been quite frequent
all along.
Herd No. 12
is the counterpart cattle herd
of this buffalo herd.
Herd started in 1938. A few
infrequent abortions.
Abortions rare; a few about
six years before test.
Abortions very rare.
Occa
sional retained placenta.