60
Paratuberculosis of Cattle in Assam
infestation or lack of proper diet, was the underlying factor. About a year
after purchase of Government animals at these farms they were reported to
have died of Johne's disease, and the presence of the disease was detected in
a majority of the indigenous stock at these farms.
The effects of Churn Brand Complete Mineral Feeding Flour in checking
the progress of the disease amongst known infected animals have been deter-
mined in the case of 15 positive reactors which were also known to have yielded
Johne's bacilli in their excreta from time to time. These animals declared
as positive reactors in March 1934 were kept under segregation, and fed on
this mineral product for about ten months during which they showed consi-
derable improvement in condition. Three to four oz. of this mixture were
given to each animal with the usual concentrate ration. On this mineral-
supplement diet the animals had not only improved in condition, but also
had shown an increase in their live-weight. In December, 1934 they were
again tested with Avian Tuberculin (as shown in Table XI) and all except two
passed the test. After the second test, repeated microscopical examination
of bowel-washings of these animals had proved negative for the organisms
of Johne's disease.
With a view to ascertaining the response of the lesion to the mineral
feed, four healthy animals of this lot were slaughtered for post-mortem
examination which revealed gross microscopic lesions typical of Johne's disease
involving the entire length of the alimentary tract. Smears prepared from
several parts of the involved gut and the mesenteric lymph glands, when
examined under the microscope after Ziel-Neelsen's staining, showed no bacilli
of Johne's disease. Pieces of intestines and the associated lymph glands
from all the four cases were sent to the Mukteswar laboratory for cultural
and histopathological examination. It was reported that the organisms
were cultured from the materials of three cases only, and in respect of the
fourth, no growth of the organisms was obtained and the bacilli of the disease
were not seen in sections prepared from several parts of the intestines, although
the histopathology of the involved tissues was typical of Johne's disease.
A tentative conclusion of this experiment is that the extra mineral feeding
provided a greater resistance and tended to retard the progress of the disease
in an infected animal which, as a result of the disease processes being more
or less completely arrested, failed to show the characteristic allergic response
to Avian Tuberculin.
Further evidence on the restorative and the prophylactic value of the
mineral-supplement diet was obtained in another experiment of a similar
nature at the Sylhet farm with 47 positive reactors (some of which were
confirmed cases) and 25 untested animals exposed to infection since calfhood.
To each adult animal 3 oz. and to each young stock 2 oz. of the minerals were
supplied per day. To the milch cows, which were 14 in number, an extra
ounce was given per day. After about nine months of this special treat-
ment these animals were tested with Avian Tuberculin, and the test revealed
14 reactors only amongst 47 old reactors and known infected cases. Out
of 25 animals which had never been previously tested only three showed
positive reaction. In a farm in which during each test of the non-reactors
and the untested animals the incidence has been recorded as over 30 per