| Information sheets | | | Elsenburg infopaks | | | Animals, diseases: 19 |
Plant poisoning in Namaqualand
Afrikaans | Xhosa
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Conditions peculiar to Namaqualand contribute towards the losses that
are sustained due to plant poisoning - for example the incidence of the
Gladdehaarbossie.
The low rainfall and the consequent weak grazing conditions often compel animals to consume more of plants which they would have avoided under better conditions. |
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Thus, for example, Abdominal dropsy causes severe losses through the excessive consumption of Kraalbos (Galenia africana). |
The system of nomadic migration between winter and summer rainfall regions results in hungry animals having to eat the only available plants along the way. However such plants, for example Asclepia en Gnidia, are often undesirable. The extensive farming practices sometimes compel stock to remain in and around pens for protracted periods, and when finally put out to graze, the famished animals are highly susceptible to poisoning. The luxuriant seedlings which appear after even light rains are highly favoured by stock that are in a poor condition. Plants of the bush-tick berry family - which are responsible for a large part of the attraction that Namaqualand has for tourists - have a very high prussic acid content which, under certain conditions, can cause severe stock losses.
Good rains in the early summer result in dense stretches of Duifiedoring (Tribulus terrestis) which causes Tribulosis. In a bad year this disease may be responsible for large-scale mortality among sheep.
Loco disease which results when the Cotyledon and Tylecodon species are eaten, is very common. The toxin accumulates in animals, and acute mortality occurs when large quantities of the plants are eaten. The protracted eating of even single plants can lead to death. The toxin can also be passed out in milk. Goat lambs that are kept in the pen die of Loco disease when the ewes have eaten these plants.
Loco disease is caused by one of the few toxins that result in secondary poisoning, for example when dogs eat from carcasses of animals that have died of the disease.
The following poisonous plants occur in Namaqualand:
| Cotyledon | Plakkie | Loco disease |
| Tylecodon | Plakkie | Loco disease |
| Ornithoglossum | Gif-ui | Heart and nerve toxin |
| Ornithogalum | Chinkerinchee | Blindness, diarrhoea |
| Thesium | Vaalstorm | Heart damage |
| Melianthus | Touch-me-not | Heart damage |
| Geigeria | Vermeerbos | Oesophageal weakening |
| Homeria | Poisonous iris | Heart, nerve poison |
| Trachyandra | Gladdehaarbossie | Muscle damage, nerve poison |
| Euphorbia | Euphorbia | Nerve poison |
| Sarcostemma | Euphorbia | Nerve poison |
| Tribulus | Devil's thorn, Duifiedoring | Bile duct damage, light sensitivity |
| Athanasia | Klaaslouwbos | Liver damage, light sensitivity |
| Asaemia | Vuursiektebos | Vuursiekte |
| Galenia | Kraalbos | Abdominal dropsy |
| Pteronia | Scholtzbossie | Liver poison |
| Ricinus | Caster-oil plant | Diarrhoea, nerve poison |
In addition to the well-known poisonous plants, there are many more that are under suspicion. These still need to be investigated in a controlled manner.
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Treatment of plant poisoning is difficult, and often treatment is only successful if the animals are treated within an hour or two after eating the plants. Activated carbon is the main antidote for poisonous plants. When it is administered at a very early stage, it binds with the poison in the rumen and in this way prevents the absorption of toxins. Raw linseed oil and lime water can protect the intestinal tube against irritating constituents of poisonous plants, and control diarrhoea. Liver stimulants can be used for Tribulosis and Abdominal dropsy, and cortisone for Loco disease, but with limited success. Hypo is effective against prussic acid, provided that it is administered early. Hypo can also be added to drinking water as a preventative measure. |
The prevention of plant poisoning depends finally on the application of such management measures as are aimed at limiting the factors that are responsible for the poisoning.
MP van Aardt
ELSENBURG / SPRINGBOK Veterinary Services
