Senecio jacobea (ragweed, St James-wort, staggerwort, cankerwort, stammerwort,
stinking nanny). Related species: S. vulgaris (groundsel); S. lautus
(common fireweed). A member of the plant family COMPOSITAE. Very common perennial
plant, with a 90cm stem, lobed broadly toothed leaves and bright yellow flowers arranged
in large, flat-topped bunches (corymbs). The fruit (akenes) are hairy with a single
Animals most affected
Cattle, horses, (all other animal species).
Note: poisoning involving S. jacobea has never been well documented in France
despite the prevalence of the plant. However in the UK there are many reported incidents
involving exposure to ragwort. The plant should thus be borne in mind when cattle
present with a hepatic syndrome of unknown etiology.
Poisoning occurs when the fresh plant material is ingested or, more frequently, when
it contaminates hay or silage.
Contains pyrrolizidine alkaloids including:
jacobine, jacodine, jaconine and retrorsine, which are all hepatotoxic. Toxicity
is maximal during the first stage of plant growth. Drying does not reduce the toxicity
of the plant.
LD quantity of fresh plant expressed as a percentage of body weight:
repeated ingestion of approximately 50-100 g fresh plant over a period of 7-8
weeks can result in hepatic lesions in cattle;
Present after a latent period of several weeks to several months. The clinical signs
are extremely diverse and without any special characteristics:
anorexia, loss of weight, constipation, mild jaundice of the mucosae;
reduction in vision followed by blindness;
ataxia with trembling, weakness, drowsiness.
Generally fatal outcome. Although acute poisoning is quite uncommon, it may result
where there has been a massive ingestion over a short time, with tachypnoea, weakness,
jaundice and death within several hours. In horses, photosensitization may develop
following ingestion of the plant.
enlargement and congestion of the liver, hepatitis (a cirrhotic form) with ascites
oedema of the abomasum.
No antidote. Symptomatic care may be attempted but is of little value.