Sudan grass-Sorghum sudanense (Piper) Stapf-Poisonous plant

Sudan grass

Other names:

Garawi (Sudan).

General poisoning notes:

Sudan grass (Sorghum sudanense) is a cultivated forage that is planted as a late-season emergency forage crop and is either pastured or cut for green feed. Some naturalized plants are occasionally found in waste places. Sudan grass can have an HCN potential after damage to the plant. It can also accumulate toxic quantities of nitrates. These problems can be avoided by proper management. Cattle are the main livestock animals that have been poisoned. In one case in California, sheep became photosensitive after ingesting Sudan grass pasture for several days. The photodynamic pigment was not determined (Gray et al. 1968, Clay et al. 1976, Fuller and McClintock 1986).

Description

Annual. Culms 1–2.5 m tall, 3–6 mm in diam. Leaf sheaths glabrous or pilose at mouth and base; leaf blades linear or linear-lanceolate; 15–30 × 1–3 cm, glabrous; ligule brown. Panicle lax, 15–30 × 6–12 cm; branches slender, branched; racemes usually tardily fragile at maturity, composed of 2–5 spikelet pairs. Sessile spikelet elliptic, 6–7.5 mm; callus hairy; lower glume leathery, thinner upward, thinly strigillose, distinctly 11–13-veined; upper lemma ovate or ovate-elliptic, apex 2-lobed, awned; awn 10–16 mm. Pedicelled spikelet male or barren, linear-lanceolate, persistent. Caryopsis elliptic or obovate-elliptic, 3.5–4.5 mm, enclosed within glumes. Fl. and fr. Jul–Sep. 2n = 20.

Nomenclature:

Scientific Name: Sorghum sudanense (Piper) Stapf

Vernacular name(s): Sudan grass

Scientific family name: Gramineae

Vernacular family name: grass

Geographic Information

Ontario, Quebec.

Notes on Poisonous plant parts:

The HCN potential is greatest in younger plants. Damage to the plant material is required for release of the volatile HCN (Gray et al. 1968).

Toxic parts:

Leaves, stems.

Notes on Toxic plant chemicals:

Sudan grass contains a cyanogenic glycoside, dhurrin, that can release HCN after plant damage such as frost, mastication, and water stress and allows plant enzymes to alter the glycoside. If enough HCN is released into the animal''s system, cyanide leads to cytotoxic hypoxia, which can result in death by asphyxiation. Nitrates can also accumulate to toxic levels in Sudan grass. A case of photosensitization occurred in sheep. A photodynamic pigment may be contained in Sudan grass (Gray et al. 1968, Clay et al. 1976, Fuller and McClintock 1986).

Toxic plant chemicals:

Dhurrin, nitrate.

Chemical diagram(s) are courtesy of Ruth McDiarmid, Biochemistry Technician, Kamloops Range Station, Agriculture and Agri-Food Canada, Kamploops, British Columbia, Canada.

Animals/Human Poisoning:

Note: When an animal is listed without additional information, the literature (as of 1993) contained no detailed explanation.

Cattle

General symptoms of poisoning:

abortion

breathing, rapid

death

death by asphyxiation

gait, staggering

methemoglobinemia

mouth, frothing of.

Notes on poisoning:

The release of cyanide into the animal''s system leads to cytotoxic hypoxia. In severe cases, death has resulted from asphyxiation. Other symptoms include increased breathing rate, irregular pulse, staggering, and frothing at the mouth. Nitrate poisoning causes methemoglobinemia, which can result in death. From 3-5 days after surviving acute poisoning, pregnant cows may abort (Gray et al. 1968, Clay et al. 1976).

Sheep

General symptoms of poisoning:

Breathing, labored, erythema, itchiness, nasal discharge.