A. L.
ROSE
191
The rabbits and goats, as controls, amply
demonstrate the virulence of the strains used in
each individual inoculation. The above results
have been obtained with standard European
strains and work is in progress to test out locally
isolated virulent bovine strains in a similar
manner.
Summary
The results of inoculating subcutaneously
eight Zebu calves and three Ankole calves with
50 mg. of a bovine strain of tubercle bacillus of
standard virulence are recorded. The Zebu calves
showed a marked resistance to tuberculous in-
fection as compared with calves of British breeds,
but the Ankole calves, on the other hand, proved
equally susceptible.
REFERENCES
Griffith, A. S. (1930): A System of Bacteriology,"
Med. Res. Council, 5, 170.
Hornby (1934): Bovine Tuberculosis in Tropical
Africa, E. Afr. med. J., 11, 9-15.
Liston, W. Glen, and Soparkar, M.B.(1917): The
Susceptibility of Indian Milch Cows to Tuberculosis,
Indian J. med. Res., 5, 19-71.
Sheather, A. L. (1921): The Virulence of tubercle
bacilli isolated from Bovine Lesions in India,
Mem. Dep. Agric. India. Vet. 3,
Soparkar, M. B. (1926): The relative susceptibility of
Indian Milch Cattle of various Breeds to Tuber-
culosis, Indian J. med. Res., 13, 755-79.
Soparkar, M. B. (1927): Virulence of Tubercle Bacilli
isolated from Cattle in India Trans. 7th Congress
of the Far Eastern Association of
Tropical
Medicine, 3, 603.
A CLINICAL SURVEY OF INTOXICATIONS OF CATTLE BY SUDAN
GRASS (SORGHUM SUDANESE)
By A. L. ROSE, B.V.Sc., District Veterinary Officer, Cootamundra, N. S. W.
(Reprinted from the Australian Veterinary Journal Vol. 7, No. 6 Dec. 1941.)
INTRODUCTION
IN the past a good many misapprehensions have
existed concerning the toxic properties of sudan
grass and its hybrids. It has been stated often
that pure sudan grass is not toxic and that mortali-
ties occur because impure seed is used by farmers.
Sorghum has always been regarded as highly toxic,
and sorghum-sudan grass hybrids are said to in-
herit the toxic properties of sorghum. Clinical
observations made during the years 1931-1938,
inclusive, throw a great deal of light on the whole
question. The clinical data concerning some
thirty-six mortalities have been tabulated and
surveyed with the object of furnishing field evi-
dence in support of certain contentions. In pre-
senting this data in tabulated form it is admitted
that much quite important clinical material has
had to be omitted., but the inclusion of all the
relevant observations would make the recorded
matter much too unwieldy in form.
During the heavy mortalities of 1931, it became
imperative to take advantage of the material
offering for investigation, and a great deal of valu-
able work was conducted at the Glenfield Veteri-
nary Research Station, much of which confirms
clinical findings and places some aspects of the
matter on a more exact basis.
The object of this article is. to record relevant
clinical observations. Discussion will be confined
to the subject matter given in the accompanying
table and will be arranged under appropriate
headings.
THE IDENTIFICATION OF PLANTS AND SEEDS
It became obvious in 1931 that allegedly pure
sudan grass seed (Sorghum Sudanese) was capable
of producing crops containing plants which differed
widely in characteristics. The so-called pure
forms consisted of heavily stooling plants bearing
a multitude of fine stalks, long narrow leaves and
uniform, fine seed. The height of the plants was
usually from two to four feet and they had the
general appearance of a 'grass'. Coarser forms
had fewer stalks, which were much thicker, grew
much taller and carried much coarser leaves and
irregularly shaped seeds. Sometimes one en-
countered a crop which looked nearly pure, while
in other cases many, or even the majority, of the
plants showed all grades of coarseness. It was
found that botanical experts had some difficulty in
giving a precise opinion upon specimens submitted
for determination, and for this reason the name
'sudan grass' as used in the accompanying table
means a plant grown from certified sudan grass
seed but which may have developed any of the
characteristics described above.
It soon became very apparent that no difference
in toxicity existed between any of the forms of
crops which developed from pure seed. In other
words, it was obvious that toxicity did not depend
upon hybridization with the coarser sorghum
species and that the fine and pure types of sudan
grass could be just as toxic as the hybrids. The
field observations on this aspect of the matter are
supported by analytical data secured by the
Veterinary Research Station.