Horse Keeping 101: Toxic Plant Awareness

Poisonous plants grow throughout North America and many can even be spotted in your own garden. Because they are so common, it is easy to mistakenly believe these poisonous plants are non-toxic. The good news is that although there are a few that can be deadly, most are not. One factor that protects our horses is their sheer size. However, some plants can lead horses to experience severe illness or death when ingested over time.  If any of these toxic plants grow in your area then try your best to learn them by sight. By knowing them you can prevent putting your horse at risk.

1. Oleander (Nerium Oleander): An evergreen shrub with thick leathery leaves. The flower, which grows in clusters, can be white, pink or red. All parts of the plant contain a naturally occurring poison that affects the heart. This is a common plant in the southern United States from California to Florida. Thirty to forty leaves can be deadly to a horse but is treatable if treated earlier by a veterinarian. Photo © by Alvesgasper

 2. Locoweed (Astragalus spp. Or Oxytropis spp.) This is a leafy perennial with short stems and leaves that grow in tuft-like forms from a single taproot. The Flowers are often white or purple. This plant grows in the West and Southwest, often in dry sandy soil. Locoweed contains swainsonine an alkaloid that after being consumed for a period of time can disrupt brain cells.

There is no treatment for advanced locoism and its effects are irreversible. Horses with less severe poisoning may recover when access to the weed is removed. 
Photo © by Colin Barker

 3.Red Maple Trees (Acer Rubrum): A medium-sized tree with green leaves in spring and summer with bright red stems and a whitish underside. In fall, the leaf turns bright red. The bark is smooth and pale grey in color and becomes darker with age. Fresh growing Red Maple leaves do little to no harm, but when the leaves wilt they become extremely toxic to horses. The toxins cause the red blood cells to break down so that the blood can no longer carry oxygen; the kidneys, liver and other organs may also be affected. Native throughout Eastern North America from Canada to Florida and West to Minnesota and Eastern Texas. Photo © by Jeff Dean.

4. Bracken Fern (Pteridum Aquilinum): A perennial fern with triangular leaves that can reach two to three feet high. Bracken fern grows in clumps in woodland and moist open areas. This fern contains thiaminase which inhibits absorptions of thiamin, which is vitamin B1. Deficiencies can lead to neurological impairment. Large amounts must be consumed to cause ill effects. However, some horses develop a taste for bracken fern and over time the toxins will build up in their system. Bracken fern grows coast to coast, except for desert climates of Southern California and the Southwest.
Photo © by Kenraiz

By Kathy Satterfield 

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