14                 The Blood Groups of Indian Cattle and Buffaloes

Usuelli [1931], in studying the blood groups of Bos taurus, found that group Ao and
Oa occurred almost exclusively in animals descendant from the Podolian breed
while Swiss and Holstein breeds belonged to group Oo, with the exception of a few Swiss
cattle of group Ao. Karshner [1928] found isoagglutinins in the blood of bovines but
states that they are less common than in the blood of man. Reactions are less frequent
among bovine animals of the same strain than among those of widely divergent strains.
Schermer [1932] states that there appears to be a difference of opinion as to whether cattle
have three or four groups.

The problem of differentiating the various breeds of cattle in India and
of deciding whether particular animals ought to constitute ' breeds' or
merely ' local varieties' is one which has exercised many minds. Until
a few years ago there was considerable disagreement on these matters among
persons qualified to express an opinion ; even now it cannot be said that
complete agreement has been reached, while the criteria that are used for classi-
fication are largely physical or morphological. The issues have now been
considerably clarified, thanks to the observation of Olver [1938] and Ware
[1939, 1941], working through the medium of the Imperial Council of Agri-
cultural Research.

No previous work has been carried out in this country on the grouping
of bovine bloods. By doing so now, it was hoped that some light might be
thrown on the origin and relationship of Indian cattle. It was necessary,
however, to determine in the first place whether blood groupings can be
accurately distinguished. The first experiments were, therefore, conducted
on cattle of the Hariana breed, a few Kumauni hill bulls, Dhanni bullocks
and on buffaloes, such as were available on the farm of this Institute. A
few samples of sera and corpuscles were also available from other cattle
breeds. Finally, a considerable number of Hariana cattle at the Govern-
ment Cattle Farm at Hissar were tested.

                                        METHODS

In view of the findings of Hopp [1920], according to which the blood-
groups in children are only established after one year of age, adult animals
only were used in these experiments. The technique for studying isoagglu-
tinins in human practice has been fully worked out but in veterinary science
much further work remains to be accomplished. At first, the slide and plate
methods, originally adopted by Moss, Lee and Vincent, quoted by Lauer
[1930], were used but those proved to be entirely unsatisfactory with cattle.
We have, therefore, used the tube method, in which a certain quantity (say
four drops) of serum is poured into small test tubes (size 7 cm. × 1 cm.) and
an equal quantity of 2 per cent corpuscle suspension added. The mixture
is then gently shaken and placed in a dry incubator at 37°C.

Serum was taken from the clot, and corpuscles by drawing blood into
small bottles containing 2.5 per cent. sodium citrate in saline—one volume
citrate solution and 10 volumes of blood. The cells were then well washed
with saline on the centrifuge.