CASE NOTES

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Tribulus Staggers

Steve Eastwood, District Veterinarian, Connabarabran RLPB

Posted Flock & Herd February 2011

History

• History important — may not be grazing tribulus when first observed
• signs may develop at least 3 months after initial exposure and can last an average of 8 months
• mainly sheep affected
• incidence is highest in British breeds and their crosses
• usually adult breeders, but occasionally hoggets may be affected
• during droughts when summer storms fall on bare cultivation profuse growth occurs
• generally only plant species available

Clinical signs

• subtle differences between T. terrestris and T. micrococcus
• initially mild paresis in hindquarter develops
• further asymmetry develops with one hind limb showing more weakness than the other
• when running affected animals move hindquarters sideways
• final stages forelimb weakness develops
• recumbency, death
• chronic, progressive and irreversible (in T. terrestris)

Gross pathology

• atrophy of hind limb muscles

Laboratory Results

• diagnosis based on History and clinical signs
• in merinos - can eliminate inherited CNS diseases by brain and spinal cord pathology

Treatment Options

• exposure to T. terrestris is irreversible
• exposure to T. micrococcus may lead to recovery
• No treatment possible
• Prevention / control of prolonged grazing only viable option

Control Options

• Control grazing — avoid prolonged grazing of Tribulus dominant pastures.