SORGHUM HELEPENSE PERS POISONING IN CATTLE AND SHEEP*
By H. S. BAWA, M. R. C. V. S., Veterinary Investigation Officer, Sind, Karachi
(Received for publication on 20 March 1943)
(With Plate XXII)
IT is well known that a large number of grasses
(Gramineae) forms an important source of palat-
able fodder for livestock. When the young
foliage is wilted or stunted by frost, injury or
drought, some plants of this family become mark-
edly poisonous to livestock on account of the
formation of excessive quantities of a cyano-
genetic glucoside which is readily converted into
hydrocyanic acid by enzymotic action. Steyn
[1929] considered this phenomenon to cause
severe losses in livestock in the arid and semi-arid
areas of South Africa ; Henrici [1926] found that
certain grasses produced prussic acid very soon
after the process of wilting had set in, whilst
others did so at a later stage.
Although considerable literature is available
in other countries on the toxicity of different
members of gramineae at different stages of their
growth, little is known in India on plants other
than Sorghum vulgare [Benson and Sobha Rao
1906; and Acharya 1933].
In this article, the poisoning of cattle and sheep
by Sorghum helepense Pers, as observed under
ordinary grazing conditions, is described.
Sorghum helepense Pers (barwari grass, Ajmer-
Merwara, dadam, N.-W.F.P., baru, Hindi) is com-
mon throughout India. It is found in areas at
all altitudes from sea level to a height of 7,000 feet.
It is a tall gregarious, perennial grass (Plate XXII)
common in cultivated and uncultivated soil and
also in hedges and along the banks of water-
courses. It, however, appears to thrive best on
well-drained soil. It is usually found in wild
state. Burtt-Davy [1903-04] considered it as one
of the most precious weeds introduced by human
agency. Bor [1941] has stated that it is very
suitable for hay if cut when not more than 3 feet
high and makes excellent silage. Whemer [1929]
and Couch [1932], however, have pointed out that
under drought conditions it may develop dan-
gerous amounts of prussic acid. Manley [1932]
and Mathews [1932] reported deaths of dairy
cows and sheep by Sorghum helepense poisoning.
Chopra and Budhwar [1940] instance Sorghum hele-
pense as one of the two (the other being Sorghum
vulgare), which, when wilted or stunted through
drought condition, have caused serious outbreak
of poisoning among livestock. They allege that
it has been responsible for serious losses of recent
years in the N. W. F. P.
Ajmer-Merwara is a typically semi-arid area
with an average rainfall of 10-12 inches. This
grass grows in abundance in a wild state in
Beawar, sub-division of Ajmer-Merwara. In the
month of May when the shoots of Sorghum hele-
pense were very young, sudden deaths of 35
sheep and two cows are reported in a herd
that grazed on the area where Sorghum helepense
was growing.
Symptoms. The chief symptoms observed were
acute colic, tympany, profuse salivation, great
excitement, shivering, anxious look, dilatation of
pupils, convulsions, coma and death within one
to two hours after the ingestion of the grass.
Cessation of respiration before that of the heart
beat was noticed.
Post mortem changes. The abdominal cavity
was greatly distended with gas, salivation was
profuse, and in some cases there was bucketful
of saliva. Blood was bright red in colour, and
cavities of the heart contained bubbles of gas.
On opening, the carcase emitted a faint smell of
bitter almonds. The entire gastro-intestinal
tract was highly inflammed. There was marked
congestion of the lung and brain.
Diagnosis. A fresh sample of the grass was
tested by [Henrici, 1926] alkaline picrate paper
test. The colour changed from yellow to red in a
very short time, indicating that the prussic acid
content was fairly high.
Besides, air dried samples were sent to the
Officer in charge, Research Unit, Medical College,
Madras, who reported that the plant contained
2.7 mg. and 5.95 mg. per 100 gm. of the dried
plant of free and total hydrocyanic acid respecti-
vely, which might be considered lethal.
Treatment. No treatment could be given, as
by the time the information of sudden deaths was
received and the suspected area visited all the
affected animals had died. Arrangements were
made, in case of any further opportunity occurring'
to bleed the animals to remove excessive prussic
acid and administer sodium thiosulphate and
sodium nitrite, as suggested by Hubert Bunyea
[1935].
It has been repeatedly observed that when the
plant is either young or the foliage is wilted,
there is a large amount of cyanogenetic glucoside.
Similar observations have been made by Hensen
[1928], Steyn [1929], Manley [1932] and Mathews
[1932]. Mature plant, however, does not produce
any harmful effect. Kehar [1942] obtained
*Under the grant of the Imperial Council of Agricul-
tural Research, New Delhi.
326