64
Investigation on Contagious Abortion in
Goats
Vol. XVIII, Part II
Brucella-positive herd
This herd consisted of 12 adult she-goats, one breeding buck and a few kids. All the adult
goats except the buck were found to be positive reactors. Of these, five were preganant, five had
kidded three to four weeks before the farm was visited and two were sterile. No proper breeding
history of this herd was available. One of the sterile goats was destroyed for the isolation of Brucella
organism but no growth occurred on crystal violet-liver infusion-agar plates sown with liver and
spleen materials of g. pigs inoculated with saline emulsions of the iliac and supra mammary lymphatic
glands of the goat. Vaginal swabs and normal saline washings from the vaginae of goats 26, 685,
753, 918 and 985 which had recently kidded were cultured and inoculated into g. pigs respectively
for the isolation of Brucella organism. No growths were observed after seven days' incubation of
crystal violet-liver infusion-agar plates inoculated with the original swab material and the spleen
and liver material of the g. pigs inoculated with the washings.
Examination of milk
About 10 c.c. of milk from each of the above five goats were collected in sterile tubes with aseptic
precautions and kept in ice undisturbed for eight hours, 2 c.c. of cream from each sample were
inoculated subcutaneously into g.pigs. The g. pig inoculated with the material from goat 26 died on
the same day but no cultural examination was made due to highly putrified state of the carcase. Milk
samples collected in the same manner and preserved in 10 per cent boric acid solution were also sent to
Mukteswar for direct cultural examination, but no organisms were recovered from these samples. The
remaining g. pigs were destroyed six weeks post injectio and their liver and spleen were cultured on
crystal violet-liver infusion-agar plates which were incubated aerobically as well as under 10 per
cent Co 2 tension at 37°C. Five days after incubation, plates exposed to Co 2 tention and sown with
the liver and spleen materials of g. pigs inoculated with the cream samples from goats 753, 918 and
985 showed colonies similar to Brucella. The colonies were picked and subcultured on liver agar
slants and grown under 10 per cent Co 2 tension.
Identification of the Brucella strains isolated
Each of the three strains was examined as follows:
1. For morphological and staining characters.
2. Against a positive Br. abortus serum.
3. For the production of H 2 S
4. For growth on Huddleson's dye media
5. For agglutinin-absorption test
6. For pathogenicity to g. pigs.
1. Morphologcial and staining characters. Culture smears were stained by Gram's method and
examined. Gram negative, short and slender rods were observed.
2. Test against a positive Br. abortus serum. Suspensions of the organisms were made in 12
per cent saline which was 0.5 per cent carbolized and adjusted to Brown's opacity tube No. 1. These,
together with the standard Br. abortus antigen, were put to agglutination test against stock Br.
abortus anti-serum. Positive agglutination was observed in high dilutions of the serum in all the
cases, thus proving that the strains under study belonged to the genus Brucella.
3. H 2 S production. The goat Brucella strains along with the known Br. abortus, Br. meletensis
and Br. suis strains were subcultured on liver infusion agar slants. Strips of filter paper dipped in
10 per cent lead acetate solution and dried were inserted so that the free ends of the strips would
hang inside the culture tubes just above the level of the media. The tubes were then incubated at
37°C (10 per cent Co 2 tension was used wherever necessary). The strips of indicator paper were
changed daily and the date and the culture number marked on them. This process was repeated for
seven days and on comparison with the known strains the goat strains of Brucella had produced