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Bacteriology of Bovine Mastitis in India
to be infected with Str. agalactiae, but from the
other Str. subacidus was again recovered.
(e) Str. pyogenes. Str. pyogenes (i.e. strongly hae-
molytic streptococci belonging to Lancefield's group
A) was not isolated from a single case.
2. Staphylococci. Staphylococci considered to have
pathogenic importance were isolated from about
20 animals. None of these strains was actually
tested for its pathogenicity, but a few were found
to be haemolytic and co-agulase positive. Their
characters are further described in Section II.
3. Diphtheroids. Many of those isolated were
obviously non-pathogenic. C. pyogenes was isolated
in practically pure culture from purulent udder
secretions of five 'field' cows and one 'field'
buffalo. Two more strains from 'field' cows
and labelled 'haemolytic diphtheroids' were pro-
bably true C. pyogenes. In all these, there was a
history of a suppurative mastitis. The cultural
and other characters of these strains corresponded to
those of classical C. pyogenes from mastitis and other
disease conditions, viz. small Gram-positive orga-
nisms, forming minute haemolytic zones in blood
agar, digesting milk and gelatine and solid serum,
and giving acid in lactose and not mannitol. Another
character, perhaps not previously described, was
their power of hydrolysing hippurate, like Str.
agalactiae, but to a somewhat lesser extent, especially
when grown in media containing a little ox-blood
serum. This property was manifested by all the
mastitis strains as well as by those from other sources.
4. Bacterium coli. Bact. coli and coliform organ-
isms were isolated from several cows. From
one cow and one buffalo at Mukteswar, haemolytic
strains of Bact. coli were recovered repeatedly and
this organism probably caused the somewhat acute
mastitis occurring in these animals.
5. Mycobact. tuberculosis. Although a number
of tests were made, there is but one case in which
tuberculosis of the mammary gland was established
by cultural and biological tests.
6. Miscellaneous bacteria. Among other bacteria
of doubtful pathogenicity, the outstanding organisms
were strains of Proteus and Pseudomonas.
SECTION II. SYSTEMATIC SURVEY
After Str. agalactiae as a cause of bovine mastitis
in India had been definitely established, it was
decided to institute a general survey of the incidence
of udder infections due to this organism in a few
organized dairy herds. The results are shown in
Table I.
MATERIAL AND METHODS
A total of 541 cows, including four buffaloes,
belonging to 15 dairy herds in different parts
of the northern India, were examined. The 16
cows included as Herd 13 really consisted of animals
admitted to the Punjab Veterinary College from
various parts of Lahore ; they are herded in this
way for descriptive purposes. Milk samples were
taken from the individual quarters of nearly all
cows available in the different herds. In a few
cases, one or more teats were 'blind', and in each
of two animals only one quarter was available.
As the main object was to determine the incidence
of Str. agalactiae infections and since it was also
desired to make some simultaneous observations
on the incidence of Staph. pyogenes infections, the
cultural technique employed was essentially the
same as that used by the English workers [Minett,
1934],. viz. to centrifuge about 10 c.c. of foremilk
collected cleanly from individual quarters and to
sow the. deposit in 5 per cent ox-blood agar plates.
As a rule, two plates were made from each sample.
In the first half of the deposit and in the second
one-tenth of this amount was taken. When the
deposits were particularly heavy or when there was
reason to suspect a high bacterial count, plates were
sown from further dilutions. Plates were examined at
24 and 48 hours incubation and the type of colonies
noted. Suspicious colonies were transferred to
one per cent serum broth for morphological study
and purification (blood agar surface). Streptococci
were tested in the following manner. Type of haemo-
lysis was noted in the primary growths from the
deposits. Intensity and character of growth in
serum broth were noted after 24 and 48 hours and
morphology was studied (chain formation, Gram-
staining.). Fermentation tests were made in lactose,
sucrose, mannitol, salicin, sorbitol, trehalose,
raffinose and inulin, all in one per cent solutions and
containing one per cent each of ox-serum and And-
rade indicator. Also noted were final pH in glucose
broth (one per cent), hydrolysis of sodium hip-
purate, changes in litmus-milk and methylene blue-
milk (1:20,000). Unless otherwise stated, observations
were made during one week at 37ºC.
RESULTS
The main results are summarized below. Table
I should be seen again.
1. Streptococci. One hundred and twenty-four
strains of streptococci, isolated from 87 cows and
one buffalo, belonging to 12 herds, were classified
as follows.
(a) Str. agalactiae was definitely diagnosed i n
two herds and suspicious strains were isolated from
three more herds. The ten suspicious strains came
from eight cows as follows : four from two cows
at Izatnagar and six from six cows in the neighbour-
hood of Lahore. The ten authentic strains of Str
agalactiae were isolated from eight cows and one
buffalo. Thus, in this survey the percentage of
animals definitely infected with this organism is
less than two.
One of the infected herds at
Mukteswar (Herd 1) contained at the time of