Lethal Beauty

Cardiac glycosides, the primary toxins in oleander, can cause an irregular or erratic heart rate, which may be racing initially, later slowing to below normal. Kidney failure, colic and CNS symptoms from drowsiness to seizures and collapse may occur. 

In the Southwest, Oleander is everywhere. Its evergreen foliage and beautiful flowers make it an attractive landscape plant, used extensively in new housing developments and along roadways. But its beauty hides a deadly danger - just four oleander leaves can kill an adult horse.  Dry leaves that blow into your horse’s paddock are as deadly as those on the plant.

From the latest UC Davis CEH Horse Report: Oleander Poisoning: The Preventable Illness -
"Oleander is one of the most poisonous plants and contains numerous toxic compounds, many of which can be deadly to people and animals. It is especially dangerous to horses, as it is sweet. Symptoms of a poisoned horse include severe diarrhea, colic and abnormal heartbeat." (Read the entire article)

Unsuspecting newcomers to the area may have oleander planted in close proximity to their horses - or your new neighbors may have planted an oleander hedge right next to your horses' turnout fence line. If this is the case, you may have to resort to offering to pay for and help plant a safer replacement. This may be much less expensive in the long run than the potential veterinary bill and can keep you on better terms with your neighbors - they likely were simply unaware that these plants could harm your horses.

Any plants that are removed should be bagged and taken off the property as soon as possible as the dried leaves are as toxic as the live plant.  Toxicity can also occur from inhaling smoke from burning oleander leaves and wood.

One of the most complete listings of poisonous plants is the Cornell University Poisonous Plants Informational Database which lists plants by both common name and scientific name.

Another excellent resource is A Guide to Plant Poisoning of Animals in North America from IVIS (International Veterinary Information Service), which lists plants by systems affected - very helpful if your horse is showing symptoms and you and your vet are trying to determine a possible cause.  Accessing IVIS does require registration (which is free).

If you’re uncertain of your skill at identifying plants you can consult with your state’s local Cooperative Extension agent to walk your land with you to identify potential problem plants.

Best regards,

Patti in Vail AZ

- where I hope to see everyone keep their horses safe.

LINKS

UC Davis CEH Horse Report http://www.vetmed.ucdavis.edu/ceh/current.cfm

Cornell University Department of Animal Science:  

Plants Poisonous to Livestock and other Animals Database 

http://www.ansci.cornell.edu/plants/index.html

International Veterinary Information System (IVIS)

A Guide to Plant Poisoning of Animals in North America

http://www.ivis.org/special_books/Knight/toc.asp

Cooperative Extension System

Each U.S. state and territory has a state office at its land-grant university and a network of local or regional offices. These offices are staffed by one or more experts who provide useful, practical, and research-based information to agricultural producers, small business owners, youth, consumers, and others in rural areas and communities of all sizes.

http://www.csrees.usda.gov/Extension/