J. B. POLDING 31
1.5 for country-bred cows, and 3.5 for crossbred cows. Thus, suscept-
ibility to abortion amongst buffaloes, country-bred cows and crossbred cows
is 1: 1 . 5 : 3.5. Applying the same calculation to buffaloes in special
environments, their susceptibility figure works out at a little over 3.
The susceptibility of sheep and goats to the Brucella types extant in
India appears at the present time to be small but the final word has yet to
be said on this subject.
Incidence of Brucellosis in India
(i) On organized farms. It is not proposed to give a list of places in India
where Brucellosis is present, it being sufficient to state that this disease can
usually be detected on almost any organized farm in the country. It may
also be added that where European blood is present and conditions of animal
husbandry are favourable the annual average loss of calves will be in the
neighbourhood of 3 per cent. In well-run indigenous herds in good climates
on the other hand the average loss may be less than 1 per cent, while in
thoroughly bad conditions the annual loss of calves amongst any type of
animal may be as high as 25 per cent.
(ii) In village or desi cattle. It is impossible to give accurate figures
for actual abortion rates amongst village cattle as no records have been kept.
It is probable, however, that Brucellosis in this class of stock is common in
Bengal and Assam; it is certainly common in Orissa, eastern and central
Madras, in the eastern and central parts of Central Provinces, and in the
south-eastern parts of Hyderabad State. It appears to be rare on the Deccan
plateau. The survey of villages north of the line from Bihar to Bombay is
not yet complete.
Conditions governing the spread of Brucellosis in India
It is, of course, quite impossible to assess accurately all the factors affect-
ing the spread of Brucellosis, but the following are probably the most important
in India ; (1) the magnitude of existing reservoirs of infection, (2) the magni-
tude and direction of cattle movements, (3) the prevailing conditions of animal
husbandry, (4) the climate and (5) the phasic susceptibility of animals. It is
the writer's opinion that, when factors (3) and (4) are favourable, the magni-
tude of existing reservoirs, even when cattle movements are considerable, is
insufficient to cause a large increase in abortion in India. The gravest possible
cause of increase in sources of infection would be, undoubtedly, an increase
in the importation of foreign cattle or an increase in cattle movement
from villages on the Eastern Seaboard of the Indian peninsula. There is also
danger of a further spread of infection from an increase of cattle movements
from a few special areas such as Calcutta or Bombay. Actually, at the
present time, where animal husbandry has been improved or is improving
and the climate is good, the existing reservoirs seem hardly sufficient to main-
tain themselves. When conditions of animal husbandry and climate are bad,
however, the smallest reservoir is probably sufficient to spread infection. As
regards animal husbandry, at present there seems to be no evidence that
ill balanced cattle feeding per se plays an important role in the spread
of Brucellosis. Indeed, it is well known that some of the best-fed herds are
the worst infected. Nevertheless, it is believed that the contamination of
food, especially cut green fodder, by animal secretions may play some part