Equis ISSN 2398-2977

Russian Knapweed (Acroptilon repens)

Synonym(s): Centaurea repens

Contributor(s): Anthony Knight, Vetstream Ltd

Introduction

  • Russian Knapweed is a creeping perennial, noxious weed.
  • Introduced from Russia, and now well established in large areas of North America.
  • Found along roadsides, cultivated areas, fields/pastures.
  • Black, horizontally branching black roots.
  • Flowers are thistle-like, spineless and range from purple to white in color   Russian Knapweed (Acroptilon repens)  .
  • The stems are stiff and leaves are alternate with toothed margins - new stems and leaves are covered in gray hairs (knap).
  • Can grow up to 2-3 feet tall, and forms monocultures as a result of inhibitory substances secreted by the roots that prevent other plant growth in the vicinity (allelopathic).
  • All parts of the plant are toxic.
  • Only horses are affected.
  • Known to cause nigropallidal encephalomalacia   Toxicity: nigropallidal encephalomalacia  .
  • Ensure removal of the plant from pastures.
  • Most horses will avoid the plant unless grazing is poor.

Toxicity

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Clinical signs

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Diagnosis

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Treatment

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Prognosis

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Larsen K A & Young S (1970) Nigropallidal encephalomalacia in horses in Colorado. JAVMA 156, 626-628 PubMed.
  • Stevens K L, Riopelle R J & Wong R Y (1990) Repin, a sesquiterpene lactone from Acroptilon repens possessing exceptional biological activity. J Nat Prod 53, 218-221 PubMed.

Other sources of information

  • Knight A & Hall J (2004) The 10 Most Dangerous Plants for Horses. Equus 320, 71-81.
  • Knight A P & Walter R G (2001) A Guide to Plant Poisoning of Animals in North America. Teton New Media, USA.
  • Burrows G E & Tyrl R J (2001) Toxic Plants of North America. Iowa State University Press, USA.
  • 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.
  • Cordy D R (1970) Centaurea Species and Equine Nigropallidal Encephalomalacia. In: Effects of Poisonous Plants on Livestock. Eds: Keeler R K, Van Kampen K R & James L F. New York Academic Press. pp 327-336.

Organization(s)

  • Cornell University - Poisonous Plants Informational Database. Website: www.ansci.cornell.edu/plants.
  • Guide to Poisonous Plants. Website: www.southcampus.colostate.edu/poisonous_plants.
  • 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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