A variety of grasses from the genus Sorghum: Sorghum vulgare (sorghum,
Sorghum bicolor, broom-corn, guinea corn, milo, schrock); S. vulgare
var. sudanese (Sudan grass, Indian corn). Related wild species:
S. halpense (Johnson grass, Aleppo grass). A member of the plant family GRAMINEAE. Valuable plants cultivated as crops in
the same manner as barley and oats. With the exception of Aleppo grass, sorghum is
used as fodder (green chop or ensilage), and grain sorghum used for feeding horses,
cattle and poultry. The flowers of the plant are terminal inflorescences which develop into large heads
of glossy small, round grain.
Animals most affected
Cattle, (sheep, goats).
Massive ingestion of sorgho or Sudan grass (a variety of sorghum) as fodder sorghum,
or sprouting green sorghum or of regrowth of the grass after harvesting.
Contains a cyanogenetic heteroside, durrhine (which yields HCN on hydrolysis). The
levels of durrhine are high in the young plant, but diminish as the plant matures.
The leaves contain more durrhine than the stems. Drought, strong sun, nitrate fertilizers
all increase the levels of HCN in Sorghum species.
1 kg leaves/500 kg body weight.
Clinical featuresIngestion of large amounts
Onset of clinical signs can be immediate if large amounts are ingested:
death in 1-2 minutes, preceded by a few convulsions and paddling movements.
Ingestion of a moderate quantity
dyspnoea, tympanism, ataxia;
collapse and falling to the ground;
paddling movements, convulsions;
death due to asphyxia may occur within a few ininutes of ingestion.
Ingestion of a small quantity
If the amount ingested is relatively small, recovery occurs within several hours,
severe congestion and cyanosis of the mucosae;
Often of little value as the onset of clinical effects is so rapid; the efficacy
of the treatment is also debatable. The following may be tried:
iv Na hyposulphite, 3 g/l00 kg;
iv Na nitrite (10% solution), 15 ml/100 kg;
iv dicobalt edetate (Kelocyanor), 20-25
Laboratory investigations Stomach contents:
to determine the levels of HCN, but care should be taken as the compound is extremely
volatile; the sample has to be very fresh or frozen immediately; to identify
fragments of ingested plant material (leaves and stems).
ensure animals graze only old sorghum, avoid new growth or recently harvested sorghum
use a medium-strength nitrate fertilizer and apply a manure which has a high phosphate
A colleague of the author made an interesting case observation which illustrates
the most common features of sorghum poisoning. A farmer had been growing sorghum
for over 20 years. The area was grazed by cattle but access to the crop was restricted
by an electric fence. The weather conditions were characteristic for July, with severe
drought. The following month there were several storms which encouraged regrowth
of the crop.
The farmer, hoping to avoid significant losses from this land, harvested the sorghum
with a silage-maker and fed his animals with all the newly harvested crop that evening.
On the morning of the next day a 4-year-old cow was found dead and a second 12-year-old
cow presented with a staggering gait, wheezing and an atonic rumen. The cow recovered
after symptomatic treatment.
In this particular case the new shoots of sorghum, rich in cyanogenetic heterosides,
had been pulverized by the silage-maker, liberating and dispersing the hydrocyanic
acid within the crop. The affected animal showed no further ill effects after its
recovery. This is a characteristic of sorghum poisoning.