Equis ISSN 2398-2977

Poisonous plants: overview

Contributor(s): Alexander Campbell, Ruth Morgan, Wilson Rumbeiha, Vetstream Ltd

Introduction

  • The most common causes of plant poisoning in horses, ragwort, yew, laburnum, hoary alyssum and bracken are usually well known to their owners.
  • Many other plants can be toxic and, if a horse is suspected of having ingested toxic herbage, veterinary help should be sought without delay.
  • Horses may suffer mild toxic effects (non-specific allergies, weight loss, lethargy, and mild digestive problems), unnoticed by owner or vet. However, reported cases of fatality by plant poisoning are rare; most toxic plants are too pungent or bitter for the horse to ingest, unless he has a craving or is exceptionally hungry.
  • Toxic plants may also be found in hay and may be more palatable when dried, eg ragwort.
  • Horses are more likely to eat poisonous plants if they are hungry or when they have insufficient access to forage. Occasionally horses appear to be addicted to certain poisonous plants and eat substantial quantities.
Print off the Owner factsheet on Poisonous plants - what to look out for to give to your clients.

Plants toxic to horses

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Clinical signs

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Prevention

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Cortinovis C & Caloni F (2013) Epidemiology of intoxication of domestic animals by plants in Europe. Vet J 197 (2), 163-168 PubMed.

Other sources of information

  • Allison K (1999) A Guide to Plants Poisonous to Horses. J A Allen & Co Ltd. ISBN 0851316980.
  • Cooper M R & Johnson A W (1998) Poisonous Plants and Fungi - An Illustrated Guide.The Stationery Office. ISBN: 0112429815.
  • Allison K & Day C (1997) A Guide to Plants Poisonous to Horses. British Association of Holistic Nutrition and Medicine.
  • Murphy M & Reagor J (1989) Toxic Plants. In: Current Therapy in Equine Medicine. Ed: Galey F D. pp 649-652.

Organization(s)

  • Cornell University - Poisonous Plants Informational Database. Website: www.ansci.cornell.edu/plants.
  • The National Archives: 1959 Weeds Act. Website: www.legislation.gov.uk/ukpga/Eliz2/7-8/54/contents.
  • ToxicologyOnline.com. Website: www.toxonline.com.
  • Veterinary Poisons Information Service (VPIS), London Center, Medical Toxicology Unit, Avonley Road, London SE14 5ER, UK. Tel: +44 (0)20 7635 9195; Fax: +44 (0)20 7771 5309.
  • Veterinary Poisons Information Service (VPIS), Leeds Center, The General Infirmary, Great George Street, Leeds LS1 3EX, UK. Tel: +44 (0)113 245 0530; Fax: +44 (0)113 244 5849.


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