260
Streptococcus Mastitis in Buffaloes
From this time onwards for the next three months
milk samples were examined from all animals prior
to their entry into the milking herd. Only animals
with negative milk samples were allowed into the
four eradication sheds. In this way it was hoped
to exclude infection. Owing to the assumed inter-
mittency of excretion of streptococci it was con-
sidered inevitable that a few infected animals would
slip through, especially as only one test was carried
out prior to entry into the herd, and this a day or
two after calving. Actually, owing to an adminis-
trative error, one known infected animal was admit-
ted to shed 8 about one month before the completion
of the experiment.
In January 1945, the whole herd was again
examined with the results shown in Table VIII.
From this table it is clear that after three months
the eradication sheds had considerably fewer infect-
ed animals than the control sheds; thus in the
eradication sheds there were 185 animals of which
25 or 13.3 per cent were infected, whereas among
the. 364 controls 122 or 33.5 per cent of the animals
were infected. In view of the fact that sheds 9,
10 and 11 were repositories for infected animals
the comparison of the eradication sheds with the
grand total of the controls is perhaps not a fair one.
However if only sheds 1, 2, 6 and 7 of the controls
are considered there will still be found to be a 10
per cent difference, since among the 209 animals in
these sheds 49 or 23.4 per cent were infected.
TABLE IX
Spread of mastitis among originally negative buffaloes
Shed No.
1
2
6
7
9
10
11
3
4
5
8
Numbers of
negative
animals in
October
1944
43
19
36
39
42
29
24
26
25
46
26
Number of
positive
in January
1945
8
1
1
4
13
14
8
3
3
3
3
Percentage
positive
in January 1945
10.2
36.8
9.8
If the observations are confined to animals nega-
tive at the first test which remained in the herd
for the whole period of three months, i.e. excluding
all new entries, an idea of the actual spread of mastitis
under different conditions will be obtained. In
Table IX we give the results of the examination of
the 355 animals concerned. In sheds 1, 2, 6 and
7 among 137 originally negative animals there were
14 or roughly 10 per cent new infections within the
three months; similarly in sheds 3, 4, 5 and 8 of
the 123 originally negative animals about 10 per
cent became infected. The removal of infected
animals had not therefore appreciably effected the
normal spread of the disease. In sheds 9, 10 and
11 where the initial infection rate was much higher
(over 30 per cent) and a constant supply of infection
was maintained, the spread to negative animals
was much more pronounced; of the 95 originally
negative animals 35 or 36.8 per cent became infected.
DISCUSSION
The data presented in this paper suggest that
streptococcus infection of the buffalo udder is a
good deal more prevalent than is generally suspected.
It would seem that infection is spread primarily by
the milkers. It is the practice here for one gawala
to attend to and milk about twelve or thirteen
animals. When infection appears, it arises in groups
of animals standing in adjacent standings; as a
rule these foci of infection are within a particular
gawala's domain and do not overlap to the next one.
A factor which may be of prime importance in
treating or eliminating mastitis is the intermittency
of excretion of streptococci; this is perhaps especial-
ly the case in buffaloes. It is clear that a single
test of the van Rensburgh type will not be sufficient
to pick out all infected animals. Referring to Table
II, for instance, it may be seen that of the 561
animals negative at the second test, 62 (11.0 per
cent) were in fact known to be infected from the
result of a previous test. This is a serious difficulty
and its only solution at the moment lies in repeated
examinations of negative animals.
In spite of the many difficulties our results tend
to show that mastitis control in buffaloes is a practical
and probably an economic proposition. By rela-
tively simple methods, we have managed to limit
the spread of the disease for the short period that
the animals were under our control. Had repeated
tests been carried out on the. negative animals, we
could presumably have reduced the incidence of
the disease still more.
In view of the present and likely future position
of the buffalo as a milk-producing animal in this
country, the most important feature brought out
by the work recorded here is the simplicity of the
technique described as a means of diagnosing strep-
tococcus infection. In this country, at any rate