List of plants poisonous to equines
Many plants are poisonous to equines; the species vary depending on location, climate, and grazing conditions. In many cases, entire genera are poisonous to equines and include many species spread over several continents. Plants can cause reactions ranging from laminitis (found in horses bedded on shavings from black walnut trees), anemia, kidney disease and kidney failure (from eating the wilted leaves of red maples), to cyanide poisoning (from the ingestion of plant matter from members of the genus Prunus) and other symptoms. Members of genus Prunus have also been theorized to be at fault for mare reproductive loss syndrome. Some plants, including yews, are deadly and extremely fast-acting. Several plants, including nightshade, become more toxic as they wilt and die, posing a danger to horses eating dried hay or plant matter blown into their pastures.
The risk of animals becoming ill during the fall is increased, as many plants slow their growth in preparation for winter, and equines begin to browse on the remaining plants. Many toxic plants are unpalatable, so animals avoid them where possible. However, this is not always the case; locoweeds, for example, are addictive and once a horse has eaten them, it will continue to eat them whenever possible, and can never be exposed to them again. When a toxic plant is ingested, it can be difficult to diagnose, because exposure over time can cause symptoms to occur after the animal is no longer exposed to the plant. Toxins are often metabolized before the symptoms become obvious, making it hard or impossible to test for them. Hungry or thirsty horses are more likely to eat poisonous plants, as are those pastured on overgrazed lands. Animals with mineral deficiencies due to poor diets will sometimes seek out poisonous plants. Poisonous plants are more of a danger to livestock after wildfires, as they often regrow more quickly.
|Scientific name||Common name||Notes||References|
|Abrus precatorius||Crab's eye||Also known as precatory bean, rosary pea, or jequirity bean|||
|Acer rubrum||Red maple, also known as swamp or soft maple||Toxic compounds are gallic acid and tannins.|||
|Adonis microcarpa||Pheasant's eye||Often found in hay.|||
|Aesculus hippocastanum||Horse chestnut||Also known as buckeye|||
|Ageratina||Snakeroots||Known poisonous species include Ageratina adenophora (Crofton weed, causes Tallebudgera horse disease) and Ageratina altissima (white snakeroot)|||
|Aleurites||Tung oil tree|||
|Amsinckia intermedia||Fiddleneck||Contains pyrrolizidine alkaloids|||
|Apocynum cannabinum||Hemp dogbane||Also known as Indian hemp, choctaw root, rheumatism weed, and snake’s milk|||
|Arctotheca calendula||Cape weed|||
|Artemisia||Known poisonous species include Artemisia tridentata (big sagebrush) and Artemisia filifolia (sand sagebrush)|||
|Asclepias syriaca||Common milkweed|||
|Astragalus||Locoweed, crazy weed, or milk vetch||Contains Swainsonine|||
|Atropa belladonna||Deadly nightshade or belladonna|||
|Berteroa incana||Hoary alyssum|||
|Celastrus scandens||Climbing bittersweet|||
|Centaurea||Thistles||Known poisonous species include Centaurea solstitialis (yellow star thistle or St. Barnaby's thistle) and Centaurea repens (Russian knapweed)|||
|Cestrum parqui||Green cestrum|||
|Chrysothamnus nauseosus||Rubber rabbitbrush|||
|Cicuta||Water hemlock, cowsbane|||
|Claviceps paspali||Paspalum ergot|||
|Conium maculatum||Hemlock or poison hemlock|||
|Craspedia chrysantha||Round billy button or woollyhead|||
|Cucumis myriocarpus||Paddy melon|||
|Dendrocnide moroides||Stinging tree or Gympie stinger|||
|Descurainia pinnata||Tansy mustard|||
|Dryopteris filix-mas||Male fern|||
|Echium plantagineum||Paterson's curse||Also known as Salvation Jane, blue weed and Lady Campbell weed|||
|Equisetum||Horsetails, mare's tails, scouring rush|||
|Erythrophleum chlorostachys||Cooktown ironwood|||
|Festuca arundinacea||Tall fescue|||
|Franseria discolor||White ragweed|||
|Glechoma hederacea||Ground ivy||Also known as creeping charlie|||
|Haplopappus heterophyllus||Rayless goldenweed||Also known as jimmyweed or burrow weed|||
|Heliotropium||Heliotropes||Known poisonous species include Heliotropium amplexicaule (blue heliotrope), H. europaeum (common heliotrope), and H. supinum (creeping heliotrope)|||
|Hypericum perforatum||St. John's wort||Also known as Klamath weed|||
|Hypochaeris radicata||Flatweed or catsear||Has been implicated in causing Australian stringhalt, possibly due to a toxic mold that grows on it, especially poisonous to draft horses|||
|Juglans nigra||Black walnut||Bedding horses in shavings or sawdust can cause laminitis|||
|Kalmia latifolia||Mountain laurel or spoonwood||Also known as spoonwood or calico bush|||
|Kochia scoparia||Burning bush||Also known as summer cypress or Mexican firewood|||
|Lantana camara||Yellow sage|||
|Lolium perenne||Perennial ryegrass|||
|Lychee||Lychee||Ingesting large amounts almost certainly caused the death of four horses|||
|Marsilea drummondii||Nardoo||Contains an enzyme which destroys vitamin B1, leading to brain damage in sheep and horses|||
|Melilotus||Sweetclover||Includes Melilotus alba (white sweetclover) and M. officinalis (yellow sweetclover), can be grazed as a forage crop, but mold or spoilage converts coumarins to toxic dicumarol, thus moldy hay or silage is dangerous|||
|Nerium oleander||Oleander||Also known as rose laurel, adelfa, or rosenlorbeer|||
|Onoclea sensibilis||Sensitive fern or meadow fern|||
|Oxytropis||Locoweed or crazy weed||Contains Swainsonine|||
|Physalis||Japanese lanterns, groundcherries|||
|Prunus||Cherries, apricots, peaches, and plums|||
|Pteridium esculentum/P. aquilinum||Bracken fern|||
|Rhododendron||Azaleas, laurels, and rose bays|||
|Ricinus communis||Castor bean||Also known as palma Christi, fatal even in small amounts|||
|Robinia pseudoacacia||Black locust||Also known as false acacia|||
|Romulea||Known poisonous species include Romulea longifolia (Guildford grass) and R. rosea (onion grass or onion weed)|||
|Rudbeckia laciniata||Goldenglow, coneflower, or thimbleweed|||
|Senecio||Ragworts, groundsel, or stinking willy|||
|Silybum marianum||Variegated thistle||Poisons cattle, sheep, and rarely horses|||
|Solanum||Potatoes, tomatoes, nightshades, horse nettle, ground cherry, or Jerusalem cherry|||
|Sorghum||Sudan grass, Johnson grass||Cyanide produced after stress|||
|Stachys arvensis||Field woundwort or stagger weed|||
|Stipa viridula||Sleepy grass|||
|Taraxacum officinale||Dandelion||When infected with a toxic mold that grows on it, the plant has been linked to outbreaks of Australian stringhalt.|||
|Trifolium pratense||Red clover|||
|Vinca major||Blue periwinkle or large periwinkle|||
|Wislizenia refracta||Jackass clover|||
|Zephyranthes atamasca||Atamasco lily or rain lily|||
- Cable, Christina (2002-04-01). "Which Trees are Toxic?". The Horse. Retrieved 2010-12-07. (Registration required (. ))
- "Poisonous Plants: Yew". Horse & Hound. 25 June 2001. Archived from the original on 18 March 2012. Retrieved 12 December 2010.
- King, Marcia (2001-05-01). "Poisonous Plants". The Horse. Retrieved 2010-12-07. (Registration required (. ))
- DeLong, Jodi (2008-10-10). "Poisonous Plant Risk Increases as Pasture Grass Goes Dormant". The Horse. Retrieved 2010-12-06. (Registration required (. ))
- "Horse Nutrition". Ohio State University. Archived from the original on 6 December 2010. Retrieved 8 December 2010.
- Israelsen, Clark E.; McKendrick, Scott S.; Bagley, Clell V. (2006-10-01). "Poisonous Plants and Equines" (PDF). Utah State University. Archived from the original (PDF) on 12 January 2011. Retrieved 2010-12-08.
- Knight, James E. (2002). "After Wildfire" (PDF). Montana State University. Retrieved 2010-12-15.
- DiTomaso, Joseph M. (1994). "List of Plants Reported to be Poisonous to Animals in the United States" (PDF). 36:49-52. Veterinary and Human Toxicology. Also, plantsciences.ucdavis.edu/PlantSciences_Faculty/Ditomaso/main/pubs.htm
- LLC, HorseDVM. "HorseDVM Toxic Plants for Horses | Red maple". HorseDVM. Retrieved 2017-07-09.
- McBarron, E.J. (1983). Poisonous Plants. Melbourne: Inkata Press. ISBN 0-09-096029-7.
- LLC, HorseDVM. "HorseDVM Toxic Plants for Horses | Summer pheasant's eye". HorseDVM. Retrieved 2017-07-09.
- Jordan, Sonia (2010-10-26). "Crofton weed". The State of Queensland. Retrieved 2010-12-06.[permanent dead link]
- "Toxic Plants in Your Hay and Pasture". University of California – Davis. Archived from the original on 4 January 2011. Retrieved 7 December 2010.
- LLC, HorseDVM. "HorseDVM Toxic Plants for Horses | Fiddleneck". HorseDVM. Retrieved 2017-07-09.
- LLC, HorseDVM. "HorseDVM Poisonous Plants in horse pastures". HorseDVM. Retrieved 2017-07-09.
- Lamm, Willis (1997). "Poisonous Plants". TrailBlazer Magazine. Retrieved 2010-12-06.
- Offord, Mellisa. "Plants Poisonous to Horses: An Australian Field Guide" (PDF). Rural Industries Research and Development Corporation, Australian Government. Archived from the original (PDF) on 15 July 2011. Retrieved 8 December 2010.
- Michigan State University Extension (2008-07-17). "Horse Owners Cautioned about Hardy Toxic Plant". The Horse. Retrieved 2010-12-07. (Registration required (. ))
- McKenzie, Ross. "Australian Native Poisonous Plants". Australian Native Plants Society. Archived from the original on 10 April 2011. Retrieved 2010-12-06.
- "Toxic Plants". Tamworth Regional Council. Retrieved 2010-12-06.[permanent dead link]
- "Common heliotrope" (PDF). New South Wales Department of Agriculture. May 2004. Retrieved 2017-02-25.
- "Common pasture weeds that may poison horses". Government of South Australia. 2008-11-20. Retrieved 2010-12-06.
- Kohnke, John. "Australian stringhalt" (PDF). South East Victoria Equine Network. Archived from the original (PDF) on 21 February 2011. Retrieved 6 December 2010.
- "Lantana (Lantana camara L.)". University of Illinois at Urbana-Champaign. Archived from the original on 26 November 2011. Retrieved 12 December 2010.
- "Our horses died from too many Lychees". Retrieved 2017-12-01.
- "Avocado". University of Pennsylvania. 2002. Archived from the original on 5 December 2010. Retrieved 7 December 2010.
- "Important Poisonous Vascular Plants of Australia". Merck & Co., Inc. 2008. Archived from the original on 17 November 2010. Retrieved 8 December 2010.