Poisonous plants for sheep

While most plants are beneficial, some are hazardous to animal and human life. Ohio has about 100 toxic plants and some of these are responsible for deaths of domestic livestock every year. The number of cases of toxicosis (plant poisoning) in livestock far outweighs those reported for humans. Accurate statistics are not available, but it is estimated that several thousand animals die annually in the U.S. from plant toxicosis.

With houses springing up everywhere in Ohio, the rural/urban interface is dramatically increasing. Many farm neighbors are unfamiliar with the plants that are toxic and many of them are found in our home landscapes. Homeowners bordering farmland or pastures should not throw yard waste over the fence or onto cropland without consulting the farmer or landowner.

The following are some common plants that are poisonous to farm animals:

Garden Iris
Grown as an ornamental plant, the iris contains an irritant in the leaves or root stalks which can produce gastroenteritis if ingested by livestock in sufficient amounts.

Holly
Common holly, a favored ornamental in landscapes around the home, has berries that are poisonous and cause vomiting, diarrhea, and stupor in animals if ingested in large amounts.

Morning Glory
Hogs, sheep, cattle and goats are especially susceptible to poisoning from overdoses of the hallucinogenic seeds produced by the morning glory.

Bracken Fern
This plant is poisonous in a fresh or dried condition causing rough hair coats, listless attitudes, and mucous discharge in ruminant animals like sheep, cattle, and goats. Elevated temperatures, swelling of the neck and difficult breathing may occur. Monogastrics, like swine, may show anorexia and incoordination.

Rhubarb
The flat leaf blade is the toxic part of the rhubarb plant that causes staggering, excessive salivation, convulsions, and death in most classes of livestock.

English Ivy
All species of livestock have exhibited toxicosis from English Ivy with symptoms including local irritation, excessive salivation, nausea, excitement, difficult breathing, severe diarrhea, thirst, and coma.

Wild Cherry
As far as plants go, wild cherry is probably the most common cause of livestock poisoning known. The most common exposure occurs when limbs are blown down or are trimmed and thrown into a fenced area. Only the wilted leaves are toxic as they produce cyanide. Wilted cherry tree leaves cause anxiety, staggering, falling down, convulsions, rolling of the eyes, tongue hanging out, loss of sensation, and dilated pupils. The animal then becomes quiet, bloats and dies within a few hours of ingestion.

Yew
This popular, needlelike shrub grown around the home contains poisonous alkaloids. Symptoms of yew poisoning are gastric distress, diarrhea, vomiting, tremors, dilated pupils, respiratory difficulty, weakness, fatigue, collapse, coma, convulsions, circulatory failure, and death. Survival after yew poisoning is rare.

Oaks
Acorns and young shoots can cause severe poisoning especially if eaten in quantity. Cattle, sheep, horses, swine will display anorexia, constipation that develops into diarrhea, gastroenteritis, thirst, and excessive urination.

Mountain Laurel
Native or wild Mountain Laurel, Rhododendron and Azalea are all considered poisonous and highly toxic to ruminants. Symptoms of poisoning include: anorexia, repeated swallowing, profuse salivation, watering of the mouth, eyes, and nose, loss of energy, slow pulse, low blood pressure, incoordination, dullness, and depression. Death is proceeded by coma.

Editors note: It pays in the long run to periodically check pastures and around the fence lines for plants that are toxic and remove them.

Adapted from an article by:
Chester D. Hughes, Extension Agent – Livestock, Penn State University

Sheep And Poisonous Plants – What Plants Are Poisonous To Sheep

If you keep a flock of sheep, whether big or small, putting them out to pasture is an essential part of each day. The sheep get to graze and roam, doing what they do best. However, there are risks to your flock if you have plants that are bad for sheep in your pasture. Protect your sheep by learning what common plants could harm them.

Plant Toxicity in Sheep

Any kind of livestock that goes out to pasture (including urban and suburban areas) and grazes is at risk for finding plants poisonous for sheep. The boundaries between rural and urban areas are blurring in some places, and this may put sheep at greater risk. Backyard sheep may encounter types of plants they wouldn’t normally see in a pasture that could be harmful to them.

With sheep and poisonous plants, it’s best to be proactive. Know the dangerous plants and remove them from the areas your sheep will graze. Also, look for signs of poor health and plant toxicity in sheep so you can get veterinary care as soon as possible.

Signs and symptoms to watch out for include:

  • Not eating
  • Vomiting
  • Staying away from the rest of the flock
  • Keeping head down, apathy, fatigue
  • Acting confused
  • Drinking an excessive amount of water
  • Difficulty breathing
  • Convulsions
  • Bloating

What Plants are Poisonous to Sheep?

Plants poisonous for sheep may be lurking in your pastures, around the edges of fields, along fence lines, and in your landscaping or garden beds. Some examples of toxic plants you may be using intentionally for landscape and garden areas include:

  • Iris
  • Holly
  • Morning glory
  • Rhubarb
  • Cruciferous vegetables (like cabbage and broccoli)
  • Yew
  • Oak
  • Oleander
  • Wild cherry
  • Mountain laurel
  • Lantana

Plants more likely to be found in a pasture that could be dangerous to your sheep include:

  • Milkweed
  • Locoweed
  • Lambsquarters
  • Snakeroot
  • St. John’s wort
  • Flax
  • Birdsfoot trefoil
  • Bracken fern
  • Black locust
  • Pokeweed
  • Common nightshade
  • Arrowgrass
  • False hellebore
  • Common ragwort

Keeping your pasture clear of toxic plants is important for the health of your flock. If you notice signs of toxicity, contact your veterinarian immediately. Search for the plant that likely caused the symptoms so you can provide more information to help with the sheep’s care.

Connect With Us!

by Martok April 22, 2013


Photo by Sue Weaver
If your sheep are sick and you don’t know why, poisonous plants in the pasture might be to blame.

This week’s question is from Sharon DeJonge, who asks, “We live in North Florida and are getting a few lambs. We have many weeds in our field. Are there any toxic ones we should worry about?”

Sharon, no matter where you live in North America, there could be plants growing on your farm that are poisonous to livestock. There are a few questions you can ask yourself to figure out if the poisonous plants will be a problem:

1. Are your sheep tempted to eat the poisonous plants?
Poisonous plants aren’t necessarily attractive to sheep. Pasture-wise animals seem to intuitively know which plants they can safely consume, and many poisonous plants taste horrid to them. Sheep (and us goats) won’t eat them unless we’re desperately hungry and we have to eat those plants to keep from starving.

2. Will your sheep eat an amount of the poisonous plants to cause concern?
Many “poisonous” plants are only toxic, so unless we eat them in massive quantities or over a length of time, they won’t really hurt us.

3. Will your sheep consume the poisonous part of the plant?
Sometimes only a portion of a plant—such as its roots, wilted leaves or seeds—is poisonous. Other times, the plant is only poisonous at certain stages of its growth, and sheep might not eat the plant at that time of the year.

4. Are your sheep immune to the compounds in a given plant?
Many poison plants are species-specific. Some humans, like my Mom, love boiled milkweed shoots, but milkweed is poisonous to sheep and goats. Goats (myself and my friends included) love poke, but poke is toxic to sheep. One species’ poison may be another species’ tasty dinner!

You should know which poisonous or toxic plants are growing in your sheep’s pasture and how to zap them if you like. Your best source of information is your cooperative-extension agent. He or she is familiar with plant species that grow in your area and how to deal with them.

You’ll also find lots of useful resources online, including sites to help you identify wild plants. Always be cautious when getting your info online, though, and make sure the writer really knows his stuff! Here are some I recommend:

  • Because most plants that are toxic or poisonous to goats are also poisonous to sheep, a good one for you is Florida A&M’s color bulletin, “Plants Poisonous to Goats and Other Livestock in the Southeast.”
  • Another great resource—especially for readers from other parts of the country or who keep additional kinds of livestock and farm pets—is Cornell University Department of Animal Science’s Plants Poisonous to Livestock website. You can click on each species for a list of poisonous plants, and then click on their scientific names to see pictures of each plant.
  • And the Maryland Small Ruminant Page’s poisonous plants and plant toxins page is a treasure trove of links to material about poisonous plants and plant toxins.

You probably won’t be able to eradicate every poisonous or toxic plant in your flock’s environment, so if one of your sheep gets sick you should keep plant poisoning in mind. If you think one of your animals has been poisoned, look for these symptoms:

  • standing alone, away from the flock or herd
  • acting confused
  • holding head down
  • refusing feed
  • drinking large amounts of water
  • vomiting

Do you have a livestock or wildlife question you want me to answer? Send me your question!

” More Mondays with Martok ”

General information for livestock

The University of Illinois Veterinary Medicine Library has a good database of plants toxic to animals (including photos and detailed description of the effects of the plants on animals): https://guides.library.illinois.edu/plantstoxictoanimals

Cornell University has a poisonous plants information database, which is arranged by type of animal, which covers horses, cattle, goats, sheep, poultry and pigs: http://poisonousplants.ansci.cornell.edu/anispecies.html

Horses

RIRDC has published a guide for horse owners to help them prevent plant poisoning in their horses: Plants Poisonous to Horses: an Australian Field Guide by Melissa Offord. You can download a PDF copy of the guide or order a hard copy from this link:

The US animal welfare organisation ASPCA runs a national poisons control centre which includes a list of the most frequently encountered plants that have been reported as having adverse effects on horses (it also provides information on pets): https://www.aspca.org/pet-care/animal-poison-control

How To Prevent Death Loss From Toxic Weeds

A weedy pasture can present a buffet of toxins to livestock.

But poisonings are rare enough, and usually light enough, that your first clue may be dead animals on the ground. And, by then, there may be more than one.

What happens more commonly is that poisoned animals just do poorly and appear unthrifty, due to a less-than-lethal dose of a toxin.

It’s rare, but it happens.

The probability of poisonings increases during and after a drought, says Pat Burch, a Virginia-based field scientist for Dow AgroSciences. But it can happen anytime.

Many common broadleaf weeds are toxic to livestock. Sheep and horses tend to be the most sensitive followed by cattle and then goats. Old and young animals are more sensitive.

Why it happens

Fortunately, livestock usually avoid more than a nibble on toxic weeds because the plants typically taste bad, smell bad, have stickers or a combination of those factors.

But there are exceptions – when something changes the desirability or palatability of these weeds.

Lack of good forage is the most common cause of poisoning. When livestock are left with little else to eat, they will go to weeds. Likewise, a mineral deficiency or an unbalanced diet may push them to new plants.

Anything that wilts the leaves of a toxic plant may, for a time, improve its palatability so animals will graze it. That wilting may be from frost, cutting or herbicides.

Take precautions

“It doesn’t take long for leaves to dry up and go crispy, but before that happens, those leaves may become more palatable,” Burch says.

“And that’s dangerous with toxic plants, especially if there’s little else there to graze.

Black cherry is notoriously toxic. If you cut a black cherry, remove the entire plant from a pasture before livestock can get to the leaves, Burch says.

“Perilla mint is toxic. If you want to spray, spray it early in the season,” he says. “Later, when forage is more limiting, animals are more likely to graze it after it’s sprayed. And the toxin level naturally goes up in the fall.”

Before you spray a pasture, take note of what your animals will have to eat as the weeds die, Burch says. If you have lots of toxic weeds, and little forage, it will be wise to find livestock another home until treated weeds are “crispy-dry.”

“There aren’t any rules of thumb about moving animals when spraying a pasture with a certain percentage of weeds,” Burch says. “So err on the side of caution.”

Other helpful resources:

Winter Treatment To Help You Get A Jump On Spring Brush Control

Pasture Clover: When Do You Sacrifice Clover For Weeed Management?

6 Tiips For Cost-Effective Weed Control

Quick Steps To Help Pastures Recover From Drought

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

  • If you suspect poisoning, call a veterinarian immediately. If death has occurred, the stomach contents should be examined for consumed herbage.
  • Identify the suspected plants. Consult your local MU Extension center or submit a plant sample:
    • Plant Diagnostic Clinic
      Weed Identification Service
      23 Mumford Hall
      Columbia, Mo. 65211.
      https://extension2.missouri.edu/programs/plant-diagnostic-clinic
  • Remove livestock from grazing area until all poisonous plants have been destroyed.
  • Eradicate poisonous plants by mowing or by applying the recommended herbicide based on the plant species present.

Common poisonous plants of Missouri

Black cherry (Prunus serotina)

  • Key descriptive characteristics
    It may have a tree or shrub appearance. The leaves are alternate, simple, pointed, leathery in texture and finely toothed on the margins. The bark of young branches is scaly and reddish brown with prominent cross-marks. Fragrant white flowers hang in drooping clusters and produce dark-red to black cherry fruits.
  • Habitat
    Low or upland woods and along streams.
  • Distribution
    All Missouri counties.
  • Poisonous part
    Damaged or wilted leaves pose the greatest risk; all parts are potentially toxic. Hydrocyanic, or prussic, acid is the responsible toxic substance.
  • Symptoms
    Anxiety, difficult breathing, staggering, convulsions, collapse and death may be sudden.

Black locust (Robinia pseudo-acacia)

  • Key descriptive characteristics
    Two short, sharp spines are present at the base of each leafstalk. Leaves are alternate and pinnately compound with oval-shaped leaflets that have entire margins. The fragrant white flowers are creamy-white and arranged in long, drooping clusters. The fruit is a flat, brown pod that contains kidney-shaped beans.
  • Habitat
    Dry or rocky upland woods, along streams, in pastures, thickets and waste ground.
  • Distribution
    Native to the Ozarks, but present in all Missouri counties.
  • Poisonous part
    Leaves, especially wilted leaves, young shoots, pods, seeds and inner bark contain three toxic substances: the protein robin, the glycoside robitin and the alkaloid robinine.
  • Symptoms
    Depression, poor appetite, weakness, paralysis, abdominal pain, diarrhea and abnormal heartbeat. Death is possible.

Black nightshade (Solanum americanum)

  • Key descriptive characteristics
    This summer annual has leaves that are alternate, simple, triangular-ovate to elliptic in shape and smooth margins. Star-shaped, white flowers, which may have tinges of purple or purple stripes, occur in clusters of 5 to 7. The fruit are small, glossy-black berries.
  • Habitat
    Occurs in open woodland, at bases of and ledges of bluffs, along streams, fallow and cultivated fields, and along rights-of-way.
  • Distribution
    Throughout Missouri.
  • Poisonous part
    All parts of the plant except the mature berries contain solanine, the toxic substance.
  • Symptoms
    Nausea, vomiting, salivation, drowsiness, abdominal pain, diarrhea, weakness, respiratory depression. Death is possible.

Bouncingbet, also known as soapwort (Saponaria officinalis)

  • Key descriptive characteristics
    The leaves are simple and opposite; they lack petioles and have entire margins. Bouncing bet generally grows to knee height. The flowers have a “phlox-like” appearance with white or pinkish white to red blossoms. Each flowering petal has a small notch at the tip. Seeds are reddish in color.
  • Habitat
    Gravel and sandbars along streams, sandy or open waste ground and rights-of-way. It is seldom encountered in wooded areas.
  • Distribution
    Throughout Missouri.
  • Poisonous part
    The toxic substance, saponin, forms a soaplike foam when mixed with water. It is found in the leaves and stems.
  • Symptoms
    The effects are delayed for several days. They include mild depression, vomiting, abdominal pain, and diarrhea.

Bracken fern (Pteridium aquilinum)

  • Key descriptive characteristics
    The leaves are erect and often inclined to one side. They are broadly triangular and usually divided into three sections, each with small, elongated segments. Small spore-sacs can be detected along the leaf margins. Creeping, hairy rhizomes are found underground.
  • Habitat
    Rocky or dry open woods, favoring acidic soils.
  • Distribution
    Primarily in the Ozark region of southern and east-central Missouri.
  • Poisonous part
    All parts contain the toxin thiaminase.
  • Symptoms
    Weakness, high fever, incoordination, convulsions.

Buttercups (Ranunculus spp.)

  • Key descriptive characteristics
    These perennial plants emerge from rootstocks or bulbs to form a rosette. Generally, the leaves are divided into three sections. The flowers occur singly and have five glossy yellow petals.
  • Habitat
    Most species are usually in moist areas of woods and pastures.
  • Distribution
    There are approximately 20 species of buttercups present in Missouri. Several species are found throughout the state.
  • Poisonous part
    Leaves and stems. The toxins contained in buttercups volatilize upon drying; therefore, buttercups contained in dried hay do not pose toxicity problems.
  • Symptoms
    The toxin causes oral and gastrointestinal irritation. Because of its immediate effects, livestock tend to avoid it.

Common cocklebur (Xanthium strumarium)

  • Key descriptive characteristics
    Stems contain black or red spots. The first pair of leaves are opposite and subsequent leaves are arranged alternately. Young leaves are triangular with three prominent veins. The leaves have a coarse texture, similar to sandpaper. The margins have coarse, irregular teeth. The egg-shaped burs are covered with stiff, hooked spines.
  • Habitat
    Primarily cultivated fields, but also fallow fields, waste areas and rights-of-way.
  • Distribution
    Throughout Missouri.
  • Poisonous part
    The entire plant may be considered toxic; however, the young seedlings and seed contain the largest amounts of toxin. The seed bur causes mechanical injury.
  • Symptoms
    Variable, because the plant contains several different toxins. Liver damage can result; ingestion of as little as 0.75 percent of an animal’s body weight can be lethal.

Field horsetail (Equisetum arvense)

  • Key descriptive characteristics
    The plant has two different appearances. In the spring, single, tan-colored, jointed shoots emerge from the underground rhizome system and terminate with cone-like structures. Later, green and sterile shoots emerge and have the appearance of a horse’s tail.
  • Habitat
    Banks of streams, ditches and commonly along railroad embankments.
  • Distribution
    Throughout Missouri.
  • Poisonous part
    All.
  • Symptoms
    See bracken fern; the plant contains the same toxin. Horses are most severely affected, while other grazing animals are moderately susceptible.

Jimsonweed (Datura stramonium)

  • Key descriptive characteristics
    Leaves are alternate, coarsely toothed and smooth with a glossy-green appearance. The plant’s foliage has a distinct, foul odor. This summer annual can grow to heights of approximately 5 feet. The tubular flowers are very showy and range in color from white to purple. Seedpods are egg-shaped and covered with prickles.
  • Habitat
    Pastures, barnyards, cultivated fields, waste areas, rights-of-way and rocky open places.
  • Distribution
    Throughout Missouri.
  • Poisonous part
    Seeds contain the greatest concentration of the toxic alkaloids atropine, hyoscyamine and hyosine. Leaves contain lower concentrations of the alkaloids. Animals will avoid grazing jimsonweed; however, the alkaloids remain in dried hay. There is no reported safe quantity of hay that can be fed to livestock.
  • Symptoms
    Signs can become readily apparent. Because the alkaloids act on the nervous system, bodily functions are affected. Animals may have dilated pupils, become agitated, have increased heart rate, tremble, become delirious, appear to be hallucinating, have convulsions, become comatose, and possibly die.

Johnsongrass (Sorghum halepense)

  • Key descriptive characteristics
    johnsongrass is a coarse perennial grass that emerges from an extensive underground rhizome system. The plant grows in dense stands, reaches heights up to 8 feet in some situations and often has reddish brown blotches on its leaves. The seed heads are large, open and loose.
  • Habitat
    Pastures, fertile cultivated fields, rights-of-way and field borders.
  • Distribution
    The plant has rapidly spread into many areas of the state; however, some northern counties are void of johnsongrass.
  • Poisonous part
    Leaves and stems possess cyanide. The young shoots are the most toxic, and when wilted or frost-damaged, cyanide becomes readily available in the leaves. Nitrates can also accumulate in johnsongrass. Well-cured hay is relatively safe for animal consumption as mature plants have much lower toxicity.
  • Symptoms
    Occur very rapidly. The animal will breathe rapidly and deeply, then become anxious and stressed. Progressing symptoms include trembling, incoordination, attempts to urinate and defecate and collapsing. Finally, respiratory or cardiac arrest may occur, leading to a violent death.

Milkweeds (Asclepias spp.)

  • Key descriptive characteristics
    Missouri has approximately 15 species of this plant. Most have a thick, milky sap in their leaves, stems and seedpods. The plant is erect-growing and has opposite, fleshy leaves (one species has whorled leaves) with entire margins. Flowers have a “globe-like” appearance and range in color from white to purplish pink. Fruit are large, angled pods with soft spines. Seeds are a flattened oval with a winged margin and have a terminal tuft of long silky hairs.
  • Habitat
    Fields, open woods, waste ground and rights-of-way.
  • Distribution
    Throughout Missouri.
  • Poisonous part
    Stems, leaves and roots contain glycosides. The sap contains a resin, known as galitoxin, which contributes to its toxicity.
  • Symptoms
    Although not eaten under normal circumstances, muscle tremors and spasms, bloat, increased heart rate, difficult breathing, and occasionally death. Toxic signs are more apparent in animals that cannot vomit, such as horses.

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

  • Key descriptive characteristics
    Collectively, the mustards have a pungent sulfurous odor. They tend to produce a basal rosette of leaves, and later produce alternate leaves along their stems. Most mustards have yellow flowers with four petals. Some of the common species in Missouri are wild mustard, field pennycress, tansy mustard, yellow rocket and Virginia pepperweed.
  • Habitat
    Fields, waste ground, pastures, rocky glades and rights-of-way.
  • Distribution
    Throughout Missouri.
  • Poisonous part
    All parts, especially seeds contain isoallyl thiocyanates, irritant oils, and under some conditions, nitrates.
  • Symptoms
    Oral and gastrointestinal irritation is most common leading to head shaking, salivating, colic, abdominal pain, vomiting and possibly diarrhea. Generally, for problems to occur, large quantities have to be consumed over a period of time.

Ohio buckeye (Aesculus glabra)

  • Key descriptive characteristics
    Leaves are opposite and are palmately compound consisting of five leaflets. Flowers are yellow and occur in clusters at the ends of branches. The fruit is prickly, glossy and leathery brown and has a pale scar.
  • Habitat
    Rich or rocky woods of valleys, ravines, slopes, bases of bluffs and thickets.
  • Distribution
    Throughout Missouri.
  • Poisonous part
    Buds, nuts, leaves, bark, seedling and honey contain aesculin and are thought to contain alkaloids.
  • Symptoms
    Both gastrointestinal and neurologic. Gastrointestinal signs occur first, with salivation, vomiting, abdominal pain and diarrhea. If enough of the toxin was ingested, neurological signs may develop, including trembling, staggering and difficult breathing.

Poison hemlock (Conium maculatum)

  • Key descriptive characteristics
    This biennial has smooth, purple-spotted stems that are hollow. The leaves are pinnately compound, highly divided with very small leaflets giving the plant a fernlike appearance. The white flowers occur in umbels (umbrella-like) and closely resemble Queen Ann’s Lace, a close relative.
  • Habitat
    Fields, pastures, fence rows, waste ground and rights-of-way.
  • Distribution
    Throughout Missouri.
  • Poisonous part
    All parts contain the toxic alkaloid, coniine and others.
  • Symptoms
    Salivation, vomiting, diarrhea, weakness, paralysis, nervousness, trembling, dilation of pupils, weak pulse, convulsions and coma.

Common pokeweed (Phytolacca americana)

  • Key descriptive characteristics
    Stems and petioles are reddish in color. Leaves are alternate, egg-shaped, smooth and glossy in appearance. The plant is a perennial; regrowth occurs from a large, fleshy taproot. The plant produces clusters of purple to black berries that contain a reddish juice and 10 seeds.
  • Habitat
    Waste areas, farm lots, fencerows, thickets and borders of woods.
  • Distribution
    Throughout Missouri.
  • Poisonous part
    All parts, especially roots and seeds.
  • Symptoms
    Irritant effects due to phytolaccigenin are salivation, abdominal pain and diarrhea. In rare cases where large doses are consumed, animals may show anemia and alterations in heart rate and respiration.

Snow-on-the-mountain (Euphorbia marginata)

  • Key descriptive characteristics
    This summer annual has alternate leaves with the upper leaves having a white margin. Flowers are very showy and white. The plant contains a milky sap.
  • Habitat
    Dry, hot and clayey soils, fields, pastures and rights-of-way.
  • Distribution
    Scattered; it is a native of the loess hills of northwest Missouri.
  • Poisonous part
    All parts.
  • Symptoms
    Nausea, vomiting and diarrhea. The toxins are diterpene esters contained in the milky sap of the plant.

Water hemlock (Cicuta maculata)

  • Key descriptive characteristics
    This perennial plant has tuberous, fleshy roots and purple-mottled, hollow stems. The leaves are alternate and two to three pinnately divided. Flowers are small and white and occur in umbrella-like clusters.
  • Habitat
    Along borders of ponds, sloughs, ditches, streams and wet depressions of pastures.
  • Distribution
    Throughout Missouri.
  • Poisonous part
    All parts, especially the roots.
  • Symptoms
    Muscle spasms, dilated pupils, dizziness, diarrhea, abdominal pain and convulsions. Reportedly, a walnut-sized portion of the root is sufficient to kill a cow.

White snakeroot (Eupatorium rugosum)

  • Key descriptive characteristics
    The plant is a perennial that regrows from roots. It has opposite, oval leaves that are finely toothed along the margins and pointed at the tip. The plant grows to a height of 4 to 5 feet. It produces small, white flowers in the late summer.
  • Habitat
    Rich or rocky woods, at the bases and crevices of bluffs, rock outcrops and thickets.
  • Distribution
    Throughout Missouri.
  • Poisonous part
    Leaves and stems; roots have lower toxicity.
  • Symptoms
    The toxic component is tremetol and the toxic dose of the green plant is 1 to 10 percent of the animal’s body weight. The onset of signs ranges from two days to three weeks, with depression, stiff gait, muscle tremors, trembling, partial throat paralysis, jaundice, passage of hard feces and prostration. Death may be sudden with no prior signs of toxicity. Because tremetol is excreted in the milk, nursing animals will be affected by the toxin.

Wild indigo (Baptisia spp.)

  • Key descriptive characteristics
    Leaves are alternate and three-parted; the plant has a shrublike growth habit. Flower color varies and depends on species. The most striking characteristic of this perennial plant is the seedpods. They are inflated and occur on stalks containing several seeds.
  • Habitat
    Prairies, glades, rocky open slopes, alluvial soils along streams and wet pastures.
  • Distribution
    Throughout Missouri.
  • Poisonous part
    All parts.
  • Symptoms
    Nausea, vomiting and diarrhea. The plant contains baptisin and cytisine, which are moderately toxic if eaten.

Woolly croton (Croton capitatus)

  • Key descriptive characteristics
    This summer annual is short and erect in stature. It has brown stems that are covered with hairs. The leaves are alternate, simple and hairy. The fruit is a three-lobed capsule.
  • Habitat
    Most commonly, the plant is found in sandy open ground, fallow fields and pastures.
  • Distribution
    Throughout Missouri.
  • Poisonous part
    All parts.
  • Symptoms
    Cattle are poisoned by the croton oil contained in the plants. It is toxic only if large quantities are consumed. Vomiting, diarrhea and nervousness are primary symptoms.
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).

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