University of Missouri Extension

G4970, Reviewed September 2001

Plants Poisonous to Livestock

Fred Fishel
Department of Agronomy

Several species of plants poisonous to livestock are distributed throughout Missouri, and many of them are commonly found in native or improved pastures. This guide describes some of the more common species that are toxic to various livestock. For more information, see your local MU Extension center, or check one of the toxic plant databases on the Web.

A common characteristic of several poisonous plants is a disagreeable taste that ordinarily discourages livestock from grazing them. Some species are poisonous only during certain stages of growth. For example, common cocklebur is most poisonous shortly before reaching the two-leaf stage. During this period of growth, cocklebur is exceedingly toxic to pigs but can also harm cattle and sheep.

If livestock poisoning is suspected, carefully examine the grazing area for poisonous plants. Jimsonweed, snow-on-the-mountain, croton and wild indigo are commonly found in open areas of the pasture. Species commonly found in shady areas include white snakeroot, bracken fern, pokeweed and buckeye. Moist areas along creeks or ditch banks are favorable for growth of water and poison hemlock, black nightshade and horsetail. Poisonous plants found in cultivated fields include cocklebur, jimsonweed, milkweed, pigweed and johnsongrass. Wild cherry, milkweed and pokeweed are found along fence and hedge rows.

What to do in case of livestock poisoning

Common poisonous plants of Missouri

Black cherry (Prunus serotina)

Black locust (Robinia pseudo-acacia)

Black nightshade (Solanum americanum)

Bouncingbet, also known as soapwort (Saponaria officinalis)

Bracken fern (Pteridium aquilinum)

Buttercups (Ranunculus spp.)

Common cocklebur (Xanthium strumarium)

Field horsetail (Equisetum arvense)

Jimsonweed (Datura stramonium)

Johnsongrass (Sorghum halepense)

Milkweeds (Asclepias spp.)

Mustards (Brassica spp., Thlaspi spp. and Lepidium spp.)

Ohio buckeye (Aesculus glabra)

Poison hemlock (Conium maculatum)

Common pokeweed (Phytolacca americana)

Snow-on-the-mountain (Euphorbia marginata)

Water hemlock (Cicuta maculata)

White snakeroot (Eupatorium rugosum)

Wild indigo (Baptisia spp.)

Woolly croton (Croton capitatus)

Line drawings of black cherry (Prunus serotina), black locust (Robinia pseudo-acacia), Ohio buckeye
(Aesculus glabra), and wild indigo (Baptisia leucantha) are reprinted, with permission, from Julian A. Steyermark's Flora of Missouri (1963, Missouri Department of Conservation).

G4970, reviewed September 2001

G4970 Plants Poisonous to Livestock | University of Missouri Extension

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