Manes & Tails Organization Horse Rescue

Dangerous Season	Scientific Name	Common Name	Habitat and Distribution	Affected Animals	Important Characteristics	Toxic Principle and Effects	Remarks and Treatment
SPRING and FALL	Cicuta spp	Water hemlock	Open, moist to wet environments; throughout	All	White flower, umbels. Veins of leaflets ending at notches. Stems hollow except at nodes. Tuberous roots from chambered rootstock.	Resinoids (cicutoxin, cicutol) in roots, stem base, young leaves. Toxicity retained when dry, except in hay. Rapid onset of clinical signs, with death in 15-30 min. Salivation, muscular twitching, dilated pupils. Violent convulsions, coma, death. Poisoning in man common.	Sedatives to control spasm and heart action. Prognosis good if alive 2 hr after ingestion.
	**Peganum harmala**	African rue	Arid to semiarid ranges; southwest	Cattle, sheep, probably horses	Multibranched, leafy, perennial, bright green, succulent herb. Leaves divided. Flowers white, single.	Alkaloids (seeds, leaves, stems; seeds more toxic). Anorexia, hindleg weakness, knuckling of fetlock, listlessness, excess salivation, subnormal temperature, pollakiuria. Lesions include gastroenteritis, with hemorrhages on heart and under liver capsule.	Unpalatable. Eaten only under drought conditions.
	**Phytolacca americana**	Pokeweed, Poke	Disturbed rich soils such as recent clearings, pastures, waste areas; eastern	Pigs, also cattle, sheep, horses, man	Tall (to 9 ft), glabrous, green, red-purple, perennial herbs. Berries black-purple, staining, in drooping racemes.	Oxalic acid, a saponin (phytolaccotoxin), and an alkaloid (phytolaccin) in all parts; roots most toxic. Vomiting, abdominal pain, bloody diarrhea, hemolytic anemia, drop in production (dairy cattle). Terminal convulsions, death from respiratory failure. Lesions include ulcerative gastritis, mucosal hemorrhage, dark liver.	Oils and protectants (GI tract). Dilute acetic acid PO, stimulants. Blood transfusion (hemolytic anemia).
	Quercus spp	Oaks	Most deciduous woods; throughout	All grazing animals, mostly cattle	Mostly deciduous trees, rarely shrubs, with 2-4 leaves clustered at tips of all twigs.	Gallotannin thought to be the toxin (young leaves and swollen or sprouting acorn). Anorexia, rumen stasis, constipation, followed by dark tarry diarrhea, dry muzzle, frequent urination, rapid weak pulse, death. Lesions include perirenal edema, nephrosis, gastroenteritis.	Diet must consist of >50% oak buds and young leaves for a period of time. Increased BUN with diet history diagnostic. Treatment symptomatic. Oral ruminatorics helpful. See also Quercus Poisoning : Introduction .
(and occasionally FALL)	Xanthium spp	Cocklebur	Fields, waste places, exposed shores of ponds or rivers; throughout	All animals, more common in pigs	Coarse annual herb. Fruit covered with spines, 2 beaked, with 2 compartments.	Carboxyatractyloside (seeds and young seedlings). Anorexia, depression, nausea, vomiting, weakness, rapid weak pulse, dyspnea, muscle spasms, convulsions. Lesions include GI inflammation, acute hepatitis, nephritis.	Seedlings or grain contaminated with seeds. Oils and fats PO may be beneficial; warmth, stimulants IM.
	Zygadenus spp	Death camas	Foothill grazing lands, occasionally boggy grasslands, low open woods; throughout	Sheep, cattle, horses	Perennial, bulbous, unbranched herbs with basal, flat, grass-like leaves. Flowers greenish, yellow, or pink; in racemes or panicles. No onion odor.	Steroidal alkaloids, glycoalkaloids, and ester alkaloids (all parts). Salivation, vomiting, muscle weakness, ataxia or prostration, fast weak pulse, coma, death. No distinctive lesions.	Seeds most toxic. Leaves and stems lose toxicity as plant matures. Atropine sulfate and picrotoxin SC.
SPRING and SUMMER	Aesculus spp	Buckeye	Woods and thickets; eastern USA and California	All grazing animals	Trees or shrubs. Leaves opposite and palmately compound. Seeds large, glossy brown, with large white scar.	Glycoside, aesculin; also alkaloids and saponins in all parts, especially seeds and leaves. Depression, incoordination, twitching, paralysis, inflammation of mucous membranes.	Young shoots and seeds especially poisonous. Stimulants and purgatives.
	**Amianthium muscaetoxicum**	Fly poison, Staggergrass, Crow poison	Open woods, fields, and acid bogs; eastern	All grazing animals	Bulbous perennial herb. Leaves basal, linear. White flowers in a compact raceme, the pedicels subtended by short, brownish bracts.	*Unidentified alkaloid, similar to those with Zygadenus* (all parts). Salivation, vomiting, rapid and irregular respiration, weakness, death from respiratory failure.**	No practical treatment. Especially dangerous for animals new to pasture. Keep animals well fed.
	**Cassia obtusifolia**	Coffeepod, Sicklepod	Found in cultivated (corn, soybean, or sorghum) and abandoned fields, along fences, roadsides; naturalized in eastern USA	All grazing animals, mostly cattle, and poultry	Annual shrub frequently found in same fields as C occidentalis . Distinguishing features include leaflets fewer in number and more rounded; seed pods long, round to 4-sided and more curved; seeds shiny, brown, and rhomboid.	*Toxic principles thought to be same as in C occidentalis* . Clinical signs, though similar, less severe with C obtusifolia .**	Treatment ineffective in down animals; salvaging most economical. Heat labile toxins not known to persist as residue. Meat from affected animals should be safe for human consumption.
	**Cassia occidentalis**	Coffee senna, Coffee weed, Styptic weed, Wild coffee	Common along roadsides, waste areas and pastures; naturalized in eastern USA	Cattle, horses, chickens, goats, sheep, rabbits	Annual herb >3 ft tall, with glandular, alternate pinnately compound leaves (8-12 ovate to lanceolate leaflets, terminal pair largest). Flowers yellow, axillary, solitary, or in short racemes. Long, flat, straight to slightly curved pods with clearly outlined seed contents. Of the pods, seeds, and wilted foliage, seeds are most toxic.	Anthraquinones (emodinglycosides and oxymethylanthraquinone), chrysarobin and lectin (toxalbumins), and alkaloids are associated with GI dysfunction and myodegeneration. Afebrile, ataxic, with diarrhea and coffee-color urine, recumbent but eat and are alert shortly before death. Increased serum CPK and isocitric dehydrogenase activities; hyperkalemia and myoglobinuria frequent. Lesions include cardiac and skeletal muscle degeneration. Congestion, fatty degeneration and centrilobular necrosis (liver) in addition to tubular degeneration (kidneys) also reported. Death probably due to hyperkalemic heart failure.	No specific treatment known. Symptomatic and supportive care essential. Although gross lesions similar to those of vitamin E/selenium deficiency, this therapy is contraindicated. Mineralocorticoid therapy may facilitate potassium excretion. Remove animals from source. Salvaging for economical reasons (see Cassia obtusifolia ).
(also seeds in FALL)	Delphinium spp	Larkspurs	Either cultivated or wild, usually in open foothills or meadows and among aspen; mostly western	All grazing animals, mostly cattle	Annual or perennial erect herbs. Flowers each with one spur, in racemes. Perennial with tuberous roots. Leaves palmately lobed or divided.	Polycyclic diterpenoid alkaloids (eg, delphinine) in all parts, fresh or dry. Straddled stance, arched back, repeated falling, forelegs first. Constipation, bloat, salivation, vomiting. Death (respiratory and cardiac failure). Most often no lesions.	Young plants and seeds more toxic. Toxicity decreases with maturity.
	Lantana spp	Lantana	Ornamentals and wild; in lower coastal plain of southeast USA, and southern California	All grazing animals	Shrubs. Young stems 4-angled. Leaves opposite. Flowers in flat-topped clusters, yellow, pink, orange, or red. Berries black.	Triterpenes (lantadene A and B) and unknowns in all parts, especially leaves and green berries. Anorexia, jaundice, watery feces, photosensitization. Lesions include degenerative change in liver and kidney. Death due to liver insufficiency, renal failure, myocardial damage.	Remove plants from pasture. Keep animals out of light sources after eating plant.
SUMMER and FALL	**Acer rubrum**	Red maple	Moist land and swamps; eastern	Horses	A large tree at maturity. Leaves opposite, 2-6 in. across, palmately 3- or 5-lobed each, roughly triangular, and coarsely toothed. Red to yellow polygamous flowers. Fruit, a pair of one-seeded winged units connected at base.	Unknown toxic principle(s) in wilted leaves. Methemoglobinemia, Heinz body anemia, and intravascular hemolysis; weakness, polypnea, tachycardia, depression, icterus, cyanosis, brownish discoloration of blood and urine.	Not common. Methemoglobinemia a prognostic indicator. Isotonic fluids, oxygen, and blood transfusion can be helpful. Methylene blue therapy not rewarding.
	Apocynum spp	Dogbanes	Open woods, roadsides, fields; throughout	All	Erect, branching, perennial herb with milky sap arising from creeping underground root stock. Leaves opposite. Flowers white to greenish white in terminal clusters. Fruit long, slender, paired, with silky-haired seeds.	A resinoid and glucoside with some cardioactivity found in leaves and stems of green or dry plants. Increased temperature and pulse, dilated pupils, anorexia, discolored mucous membranes, cold extremities, death.	IV fluids and gastric protectants suggested.
	**Centaurea repens**	Russian knapweed	Waste areas, roadsides, railroads, and overgrazed rangeland; not common on cultivated or in irrigated pastures; mostly western and upper midwestern USA	Horses	Perennial weed with slender rhizomes. Stems erect and well branched. Leaves pinnately lobed to entire, not spiny, narrowed basally but not petioled and of decreasing length up the plant. Thinly pubescent or glabrous. Blue, pink, or white flowers. One-seeded fruit with whitish, slightly ridged attachment scar.	Unidentified alkaloid in fresh or dried plant. Chronic exposure, acute onset of signs. Inability to eat or drink, facial dystonia, chewing, yawning, standing with head down, severe facial edema, gait normal, head pressing, aimless walking or excitement most severe the first 2 days, become static thereafter. Death from starvation, dehydration, aspiration pneumonia.	*More toxic than C solstitialis* (see below) but with similar pathology and prognosis. Some relief with massive doses of atropine but not an effective treatment. Euthanasia recommended.**
	**Centaurea solstitialis**	Yellow star thistle, Yellow knapweed	Waste areas, roadsides, pastures; mostly western	Horses	Annual weed. Leaves densely covered with cottony hair. Terminal spreading cluster of bright yellow flowers with spines below. Branches winged.	Unidentified alkaloid. Involuntary chewing movements, twitching of lips, flicking of tongue. Mouth commonly held open. Unable to eat; death from dehydration, starvation, aspiration pneumonia.	Horses graze because of lack of other forage. Extended period of consumption essential for toxicity. Liquefactive necrosis of substantia nigra and globus pallidus (brain) pathognomonic. No treatment. Euthanasia recommended.
	**Eupatorium rugosum**	White snakeroot	Woods, cleared areas, waste places, usually the moister and richer soils; eastern	Sheep, cattle, horses	Erect perennial herb. Tremetol leaves, opposite, simple, serrated. Flowers small, white, and many. Often grows in large patches.	Complex benzyl alcohol (tremetol in leaves and stems). Excreted via milk; cumulative. Weight loss, weakness, trembling (muzzle and legs) prominent after exercise, constipation, acetone odor, fatty degeneration of liver, partial paralysis of throat, death in 1-3 days.	“Milk sickness or trembles.” Treatment symptomatic. Heart and respiratory stimulants and laxative may be necessary. Remove animal from access to plant, discard milk (hazardous to man).
	**Perilla frutescens**	Perilla mint, Beefsteak plant	Ornamental originally from India, escaped to moist pastures, fields, roadsides, and waste places; eastern	Cattle primarily, horses and other livestock susceptible	Annual, freely branched, squared stems. Opposite, purple or green, coarsely serrated leaves. White to purple flowers. Strong pungent odor when crushed.	Green or dry, 3-substituted furans (perilla ketone, egomaketone, isoegomaketone). Signs 2-10 days after exposure include dyspnea (especially on exhaling), open-mouth breathing, lowered head, reluctance to move, death on exertion. Lesions include pulmonary emphysema and edema.	Treatment ineffective once clinical signs severe. Parenteral steroids, antihistamines, and antibiotics may help. Handle gently (prevents exertion and death). Seeds produce edible oil.
	**Robinia pseudoacacia**	Black locust, False acacia, Locust tree	Open woods, roadsides, pinelands, on clay soils preferably; eastern USA	All grazing animals, mostly horses	Tree or shrub. Deciduous, alternate, pinnately compound (>10 elliptic to ovate leaflets) leaves. Pair of spines at base of each leaf. Flowers in loose, fragrant, white to cream, drooping racemes. Flattened, brown pods containing 4-8 seeds persist throughout winter.	The glycoside robitin, a lectin (hemagglutinin), and the phytotoxins robin and phasin found throughout plant, although flowers have been suggested as the toxic principles. Diarrhea, anorexia, weakness, posterior paralysis, depression, mydriasis, cold extremities, frequently laminitis and weak pulse. Death infrequent; recovery period extensive. Postmortem lesions restricted to GI tract.	Laxatives and stimulants suggested. Treatment symptomatic.
	Solanum spp	Nightshades, Jerusalem cherry, Potato, Horse nettle, Buffalo bur	Fence rows, waste areas, grain and hay fields; throughout	All	Fruits small; yellow, red, or black when ripe; structurally like tomatoes; clustered on stalk arising from stem between leaves	Glycoalkaloid solanine (leaves, shoots, unripe berries). Acute hemorrhagic gastroenteritis, weakness, excess salivation, dyspnea, trembling, progressive paralysis, prostration, death.	Pilocarpine, physostigmine, GI protectants. Seeds may contaminate grain.
FALL and WINTER	**Allium cepa , A canadense**	Onions (cultivated and wild)	Cultivated and grown on rich soils throughout USA.	Cattle, horses, sheep, dogs	Biennials and perennials, bulb plants, onion odor; leaves basal, green, hollow, cylindrical ( A cepa ), lustrous green, flat ( A canadense ); flowers on hollow flowering stalks, terminal umbels of many small blooms; fruits 3-celled capsules with many seeds.	N-propyl disulfide, an oxidant, in all parts. Livestock readily consume cull or overproduced onions, with anemia developing within days of exposure. Toxicosis in cattle associated with prolonged ingestion of large amounts of onions. N-propyl disulfide inhibits RBC glucose-6-phosphate dehydrogenase, leading to hemolysis and formation of Heinz bodies. Observed clinical signs are hemoglobinuria, diarrhea, loss of appetite, jaundice, ataxia, collapse, and possible death if untreated. Hemolytic anemia reported in livestock ingesting wild onions. Heinz body anemia; swollen, pale, necrotic liver; hemosiderin in liver, kidneys, and spleen are reported pathologic lesions.	Clinical presentation similar to S-methylcysteine sulfoxide (a rare toxic amino acid in Brassica spp )-induced toxicity in livestock. Susceptibility to onion poisoning varies across animal species: cattle > horses and dogs > sheep and goats. Remove animals from source and prevent future access to cull onions. Symptomatic and supportive care essential.
	*Daubentonia (Sesbania) punicea*	Rattlebox, Purple sesbane	Cultivated and escaped, in waste places; southeastern USA coastal plain	All	Shrub. Flowers orange. Legume pods longitudinally 4-winged.	Rapid pulse, weak respiration, diarrhea, death.	Seeds poisonous. Remove animal from source. Saline purgatives.
	**Haplopappus heterophyllus**	Rayless goldenrod, Burroweed	Dry plains, grasslands, open woodlands, and along irrigation canals; southwest	Cattle, sheep, horses	Bushy perennial 2-4 ft tall, with many yellow flowerheads. Leaves alternate, linear, sticky.	Complex benzyl alcohol (tremetol); resin acid; primarily nursing young and nonlactating animals. Reluctance to move, trembling, weakness, vomiting, dyspnea, constipation, prostration, coma, death.	“Milksickness.” Remove young and discard milk (hazardous to man).
	**Juglans nigra**	Black walnut	Native to eastern USA; now from eastern seacoast, west to Michigan and most of the Midwest, south to Georgia and Texas	Horses	Tree with deciduous, alternate, pinnately compound leaves (numerous lanceolate leaflets with serrated margins); leaflets in middle are largest. Male and female flowers on same tree but different inflorescences. Thick husk nut does not open when ripe. Twigs have chambered pith.	Juglone, phenolic derivative of naphthoquinone. Shavings with <20% black walnut toxic within 24 hr of exposure. Reluctance to move; depression; increased temperature, pulse, respiration rate, abdominal sounds, digital pulse, hoof temperature; distal limb edema; lameness. Severe laminitis with continued exposure.	Nonfatal; laminitis and edema of lower limbs. Remove shavings promptly. Treat for limb edema and laminitis. Improvement in 24-48 hr with no sequelae.
	**Melilotus officinalis and M alba**	Sweet clover, White sweet clover	Commonly found on alkaline soils, fields, roadsides, and waste places; forage crop in southern and northern USA	Most commonly cattle, also horses and sheep	Annual or biennial herb 3-6 ft tall. Leaves alternate, pinnately compound with 3 obovate leaflets, serrated margins. Yellow or white flowers borne on racemes. Small one-seeded pods.	See sweet clover poisoning, Sweet Clover Poisoning: Introduction .	See Sweet Clover Poisoning: Introduction.
	*Sesbania (Glottidium) vesicaria*	Bladderpod, Rattlebox, Sesbane, Coffeebean	Mostly open, lowground, abandoned cultivated fields; southeastern USA coastal plain	All	Tall annual. Legume pods flat, tapered at both ends, 2-seeded. Leaves pinnate, divided. Flowers yellow.	Unknown (green plant and seeds). In ruminants, hemorrhagic diarrhea, shallow rapid respiration, fast irregular pulse, coma, death. Lesions include hemorrhages in abomasum and intestines, dark tarry blood.	Green seeds are more toxic. Remove animal from source immediately. General supportive treatment—saline purgatives, rumen stimulants, IV fluids.
	**Agrostemma githago**	Corn cockle	Weed, grainfields, and waste areas; throughout	All	Green winter annual with silky-white hairs, opposite leaves, purple flowers, black seeds.	Saponin (githagenin) in seeds. Acute course. Profuse watery diarrhea, vomiting, dullness, general weakness, tachypnea, hemoglobinuria, death.	Oils and GI protectants. Neutralize toxin (dilute acetic acid PO). Blood transfusions may be necessary.
	Asclepias spp	Milkweeds	Dry areas, usually waste places, roadsides, streambeds	All	Perennial erect herbs with milky sap. Seeds silky-hairy from elongated pods.	Steroid glycosides and toxic resinous substances (all parts), green or dry. Staggering, tetanic convulsions, bloating, dyspnea, dilated pupils, rapid and weak pulse, coma, death.	Sedatives, laxatives, and IV fluids suggested.
	Astragalus spp , Oxytropis spp (certain species only)	Locoweed	Mostly western	All grazing animals	Stemmed or stemless perennial herbs. Leaves alternate and pinnately compound. Flowers leguminous. Chronic intoxication.	Swainsonine. Depression, emaciation, incoordination, dry lusterless hair. Abortions. Neurovisceral cytoplasmic vacuolation. Congestive right heart failure in cattle grazing at high altitudes.	Avoid grazing of source. Both green and dry plants toxic.
	Astragalus spp (certain species only)	Milk vetch, etc (many common names)	Nearly all	All grazing animals	As above.	Miserotoxin, other aliphatic nitro compounds. Posterior paralysis, goose-stepping, depression, rough coat, pulmonary emphysema, acute death, cord demyelination.	Avoid grazing of pre-flower stage.
	Astragalus spp (certain species only—selenium accumulators)	Many common names	Seleniferous areas, mostly western and midwestern	All grazing animals	As above.	Selenium (chronic). Slow growth, reproductive failure, loss of hair, sore feet, acute death.	*Avoid grazing seleniferous plants for extended periods. See* selenium poisoning, Chronic Selenium Poisoning: Overview.**
	Brassica , Raphanus , Descurainia spp	Mustards, Crucifers, Cress	Fields, roadsides; throughout	Cattle, horses, pigs	Annual herbaceous weeds with terminal clusters of yellowish flowers and slender, elongated seed pods.	Glucosinolates (isothiocyanate, thiocyanates, nitrites) in seeds and vegetative parts, fresh or dry. Acute/chronic course. Anorexia, severe gastroenteritis, salivation, diarrhea, paralysis, photosensitization, hemoglobinuria.	Remove from source. Administer GI protectants (mineral oil).
	**Cestrum diurnum , C nocturnum**	Day-blooming jessamine and Night-blooming jessamine, respectively	Open woods and fields; gulf coast states (Florida, Texas) and California	Cattle, horses, and dogs (ingesting cholecalciferol-based rodenticides)	Evergreen shrubs or tall bush; leaves alternate, ovate smooth-edged; flowers white, tubular, small clusters, fragrant by day; fruit, a greenish-white to lavender (immature), becoming dark-purple to black (mature), fleshy berry, with several small, black, oblong seeds, dispersed by birds in droppings. Leaves longer, night fragrant flowers, white fruits at maturity ( C nocturnum ).	Atropine-like alkaloids (fruit), saponins (fruit and sap), and glycosides of 1,25-dihydroxycholecalciferol (leaves primarily, stem, fruits, and roots) are found. Gastroenteritis develops on ingestion of fruits. Vomiting, depression, anorexia, chronic weight loss with normal appetite, choppy stiff gait, increased pulse, persistent hypercalcemia and hyperphosphatemia, calcinosis (aorta, carotid and pulmonary arteries, tendons, ligaments, and kidneys), parathyroid atrophy, thyroid (C-cell) hypertrophy, and osteopetrosis reported with chronic ingestion of leaves.	Prevent further access of animals to plants. In early stages, treatment might be effective and cost effective. Correct fluid and electrolyte imbalances in cases with persistent vomiting or diarrhea. Reduce or prevent hypercalcemia (calciuresis, diuretics, steroids, calcitonin). Maintenance therapy of diuretics and steroids may be necessary.
	**Conium maculatum**	Poison hemlock	Roadside ditches, damp waste areas; throughout	All	Purple-spotted hollow stem. Leaves resemble parsley, parsnip odor when crushed. Tap root. Flowers white, in umbels.	Piperidine alkaloids (coniine and others) in vegetative parts. Acute course. Dilated pupils; weakness; staggering gait; slow pulse, progressing to rapid and thready. Slow, irregular breathing; death from respiratory failure. Teratogenic in cattle.	Coniine excreted via lungs and kidneys, mousy odor of breath and urine diagnostic. Administer saline cathartics; neutralize alkaloids with tannic acid, together with stimulants.
	Crotalaria spp	Crotalaria, Rattlebox	Fields and roadsides; eastern and central USA	All	Annual or perennial legume. Yellow flowers in racemes, pods inflated. Bracts at base of pedicels of flowers and fruits persistent. Leaves simple or divided. Seeds in harvested grain.	Pyrrolizidine alkaloid (monocrotaline) and other unidentified alkaloids (all parts, especially seeds). Chronic course. Chickens—diarrhea, pale comb, ruffled feathers; horses—unthriftiness, ataxic, walking in circles, icterus; cattle—bloody diarrhea, icterus, rough coat, edema, weakness. Death may occur from a few weeks to months after ingestion.	Cumulative, fresh or dry. No treatment.
	**Cynoglossum officinale**	Hound’s tongue	Commonly grown in waste places, roadsides, and pastured areas throughout USA.	Cattle, sheep, horses	Annual or biennial herbaceous plant, rough-hairy stem and foliage, 3-4 feet tall; leaves alternate, oblanceolate, narrowed to petiole (lower), lanceolate, sessile, clasping (upper); flowers numerous in coiled racemes, without bracts, blue, purple, or white blooms; fruit, bur-like from four nutlets, thickly covered with hooked prickles.	Pyrrolizidine alkaloids (0.6-2.1% of dry matter) including heliosupine and echinatine in the foliage. Unpleasant odor discourages consumption when fresh, becomes palatable in hay and is readily consumed. Toxic insult primarily hepatic and chronic in nature. Pyrrolizidine alkaloids (inactive) undergo hepatic metabolization to active intermediates—pyrroles (alkylating agent), which are toxic. Clinical signs are anorexia, depression, rough hair coat, hemorrhage, tenesmus, bloody feces, ataxia, jaundice, death. Hepatic lesions of necrosis, edema, megalocytosis, bile duct hyperplasia, and cytoplasmic vacuolation reported.	Know source and quality of hay. Symptomatic and supportive at best. Affected animals seldom recover.
	**Datura stramonium**	Jimson weed, Thorn apple	Fields, barn lots, trampled pastures, and waste places on rich bottom soils; throughout	All	Leaves wavy. Flower large (4 in.), white, tubular. Fruit a spiny pod, 2 in. (5 cm) long.	Tropane alkaloids (atropine, scopolamine, hyoscyamine) in all parts, seeds in particular. Acute course. Weak rapid pulse and heartbeat, dilated pupils, dry mouth, incoordination, convulsions, coma.	All parts, mainly in hay or silage. Urine from animal dilates pupils of laboratory animals (diagnostic). Treatment nonspecific; cardiac and respiratory stimulants (physostigmine, pilocarpine, arecoline).
	**Festuca arundinacea**	Tall fescue	A coarse, hardy, drought-resistant grass; Pacific Northwest, Missouri, Oklahoma, and Kentucky; major pasture grass in southeastern USA	Mostly cattle and horses	Coarse, deeply rooted perennial grass. Broad, dark-green, ribbed, rough upper surface, and smooth sheathed leaves. Grows in clumps.	See fescue poisoning, Fescue Lameness .	See Fescue Lameness.
	**Gelsemium sempervirens**	Yellow jessamine, Evening trumpet flower, Carolina jessamine	Open woods, thickets; southeast	All	Climbing or trailing vines. Evergreen, entire, opposite leaves. Yellow tubular flowers, very fragrant.	Alkaloids (gelsemine and others, related to strychnine) in all parts. Acute course. Weakness, incoordination, dilated pupils, convulsions, coma, death within 48 hr. Limberneck in fowl.	No specific treatment. Relaxants and sedatives suggested.
	*Helenium (Dugaldia) hoopesii*	Orange sneezeweed	Moist slopes and well-drained mountain meadows; western	Sheep, rarely cattle	Perennial herb. Orange sunflower-like heads or yellow flowers. Leaves alternate.	Sesquiterpene lactones (helenalin, hymenoxin). Subacute course (spewing sickness). Depression, weakness, restlessness, stiff gait, salivation, pronounced vomiting, emaciation, eventual death.	Cumulative. Aspiration pneumonia frequent. Remove from access to plant. Graze sneezeweed areas for only short periods of time. Can graze intermittently with some success.
	**Hypericum perforatum**	St. John’s wort, Goatweed, Klamath weed	Dry soil, roadsides, pastures, ranges; throughout	Sheep, cattle, horses, goats	Perennial herb or woody below. Leaves opposite, dotted. Flowers many, yellow, with many stamens.	Photodynamic pigment (hypericin). Subacute course. Photosensitization, pruritus and erythema, blindness, convulsions, diarrhea, hypersensitivity to cold water contact, death.	Remove animals from source and sunlight. Corticosteroids parenterally, topical broad-spectrum antibiotics.
(especially WINTER and SPRING)	Kalmia spp	Laurel, Ivybush, Lambkill	Rich moist woods, meadows, or acid bogs; eastern and northwestern	All, often sheep	Woody shrub. Evergreen, glossy leaves. Flowers pink to rose, showy.	Resinoid (andromedotoxin) and a glucoside (arbutin) in vegetative parts. Acute course. Incoordination, excess salivation, vomiting, bloat, weakness, muscular spasms, coma, death.	Undigested rumen contents and ingesta in lungs at necropsy. Laxatives, demulcents, nerve stimulants, atropine.
	Ligustrum spp	Privet, Ligustrum, Hedge plant	An ornamental; common as hedge; found at abandoned farm home sites, along fences, and in bottom lands.	All livestock	Shrubs up to 15 ft tall. Simple, opposite, short-petioled, evergreen or deciduous leaves. Numerous small, white flowers in panicles. Fruit is 1- to 2-seeded, black or dark blueberry that persists throughout winter.	Ligustrin, ligustron, syringin, syringopictrin, and other unknown compounds in leaves and fruit. Primarily GI irritants. Diarrhea, abdominal pain, incoordination, paresis, weak pulse, hypothermia, convulsions, sometimes death.	Treatment symptomatic and supportive; correct dehydration.
	Lupinus spp	Lupines, Bluebonnet	Dry to moist soils, roadsides, fields, and mountains; throughout, but poisoning mostly western	Sheep, cattle, goats, horses, pigs	Perennials. Leaves simple or palmately divided. Flowers blue, white, red, or yellow in terminal raceme.	Quinolizidine alkaloids (20 known) concentrated in seeds (fresh and dry); some piperidine alkaloids. Acute course. Inappetence, dyspnea, struggle, convulsions, death from respiratory paralysis. Some species teratogenic in cattle.	*Do not disturb sick animals; remove from source as they begin to recover. No effective treatment, but survivors recover completely. See also* Mycotoxic Lupinosis .**
	**Nandina domestica**	Nandina, Heavenly bamboo, Chinese sacred bamboo	Common ornamental in southern USA	All grazing animals, especially ruminants	Upright, unbranched, and multistemmed, evergreen shrub, 3-7 ft tall. Alternate, bi- to tripinnately compound leaves; leaflets subsessile, elliptic-lanceolate, half as wide as long, entire, leathery, metallic bluish-green becoming purple in fall. Small, white flowers; 2-seeded, bright red berries in large panicles persist throughout fall and winter.	Cyanogenic glycosides in foliage and fruits, hydrolyzed in GI tract to free cyanide, thereby affecting cellular respiration. See cyanide poisoning , Cyanide Poisoning: Introduction. Prognosis good if animal survives for 1 hr after signs begin.	Acute outcome precludes effective treatment for most; IV sodium nitrite/sodium thiosulfate treatment of choice. Picrate test indicates toxic potential of the plant. See cyanide poisoning , Cyanide Poisoning: Introduction.
	**Nerium oleander**	Oleander	Common ornamental in southern regions	All	Evergreen shrub or tree. Leaves whorled and prominently, finely, pinnately veined beneath. Flowers showy, white to deep pink.	Digitoxin-type glycosides (oleandroside, nerioside, and others) in all parts, fresh or dry. Acute course. Severe gastroenteritis, vomiting, diarrhea, increased pulse rate, weakness, death.	No specific treatment. Atropine in conjunction with propranolol reported helpful.
	**Photinia fraseri , P serrulata ,Pglabra**	Fraser’s photinia, Chinese photinia, Red leaf photinia, Red tip photinia	Common ornamental (hedge or screen) in southern USA	All grazing animals, mostly ruminants	Evergreen shrubs, 10-15 ft tall. Alternate, oblong-ovate serrated leaves, copper-red (when young) turning dark green in 2-4 wk. Prominent, whitish flowers in spring; showy, red berries in fall.	Cyanogenic glycosides in foliage and fruits, hydrolyzed in GI tract to free cyanide, thereby affecting cellular respiration. See cyanide poisoning , Cyanide Poisoning: Introduction. Prognosis good if animal survives for 1 hr after signs begin.	Acute outcome precludes effective treatment for most; IV sodium nitrite/sodium thiosulfate treatment of choice. Picrate test indicates toxic potential of the plant. See cyanide poisoning , Cyanide Poisoning: Introduction.
(especially WINTER and SPRING)	**Prunus caroliniana**	Laurel cherry, Cherry laurel	Woods, fence rows, and often escaped from cultivation; southern regions	All grazing animals	Leaves evergreen, shiny, leathery. Broken twigs with strong cherry bark odor. Fruit black.	Hydrocyanic acid (wilted leaves, bark, and twigs). Peracute course. Difficult breathing, bloat, staggering, convulsions, followed by prostration and death. Mucous membranes and blood bright red.	See cyanide poisoning, Cyanide Poisoning: Introduction .
	Prunus spp	Chokecherries, Wild cherries, Peaches	Waste areas, fence rows, woods, orchards, prairies, dry slopes	All grazing animals, mostly cattle and sheep	Large shrubs or trees. Flowers white or pink. Cherries or peaches. Crushed twigs with strong odor.	Glycoside-yielding cyanide (rumen hydrolysis). Excitement leading to depression, dyspnea, incoordination, convulsions, prostration; death may occur in 15 min from asphyxiation.	*Mucous membranes, bright pink color; blood, bright red color. See* cyanide poisoning, Cyanide Poisoning: Introduction .**
	**Pteridium aquilinum**	Bracken fern	Dry poor soil, open woods, sandy ridges	All grazing animals	Leaves firm, leathery, 3-pinnate.	See bracken fern poisoning, Bracken Fern Poisoning : Introduction .	See Bracken Fern Poisoning : Introduction.
	**Ricinus communis**	Castor bean	Cultivated in southern regions	All	Large, palmately lobed leaves. Seeds resembling engorged ticks, usually 3 in somewhat spiny pod.	Phytotoxin—ricin in all parts (seeds especially toxic). Acute to chronic course (death or recovery). Violent purgation, straining with bloody diarrhea, weakness, salivation, trembling, incoordination.	Diagnosis based on presence of seeds, RBC agglutination, precipitin test. Specific antiserum, ideal antidote; sedatives, arecoline hydrobromide, followed by saline cathartics suggested.
	Senecio spp	Groundsel, Senecio	Grassland areas; mostly western	Cattle, horses, sheep to a limited extent in USA	Perennial or annual herbs. Heads of yellow flowers with whorl of bracts below.	Pyrrolizidine alkaloids, volatile oils, and nitrogen oxides (fresh or dry). Acute poisoning not common. Dullness, aimless walking, increased pulse, rapid respiration, weakness, colic, delayed death (days to months). In cattle, prolapsed rectum from persistent straining. In horses, nervous signs evident in later stages.	*Liver biopsy diagnostic in early stages. Liver function test of value for subclinical condition in cattle. No general treatment. See also* Pyrrolizidine Alkaloidosis: Introduction.**
	**Sorghum halepense**	Johnson grass	Weed of open fields and waste places; southern and scattered north to New York and Iowa	All grazing animals	Coarse grass with large rhizomes and white midvein on leaf. Topped by large, open panicle.	Hydrocyanic acid (drought, trampling, frost, second growth) and nitrate (heavy fertilization, drought) in vegetative parts. Acute course. Difficult breathing, bloat, staggering, convulsions, death. Blood bright red (cyanide) or chocolate brown (nitrate).	Hay safe for cyanide (volatile), not safe for nitrate (analyze). See cyanide poisoning, Cyanide Poisoning: Introduction , and nitrate and nitrite poisoning, Nitrate And Nitrite Poisoning: Introduction .
	**Sorghum vulgare**	Sorghum, Sudan grass, Kafir, Durra, Milo, Broomcorn, Schrock, etc	Forage crops and escapes; throughout	All	Coarse grasses with terminal flower cluster. Some to 8 ft tall.	Hydrocyanic acid (drought, trampling, frost, second growth) and nitrate (heavy fertilization, drought) in vegetative parts. Acute course. Difficult breathing, bloat, staggering, convulsions, death. Blood bright red (cyanide) or chocolate brown (nitrate).	Hay safe for cyanide (volatile), not safe for nitrate (analyze). See cyanide poisoning, Cyanide Poisoning: Introduction , and nitrate and nitrite poisoning, Nitrate And Nitrite Poisoning: Introduction .
	Taxus spp	Yew	Most of North America; Japanese and English yew common ornamentals	All	Evergreen perennial tree or shrub. Bark reddish brown then flaking in scales. Leaves linear, 0.5-1 in. (1.5-2.5 cm) long, 2 ranked on twig, upper surface dark green, lower yellow-green, midribs prominent. Flowers unisexual, inconspicuous. Fruit single stony seed. Bright scarlet color.	Toxic alkaloids in bark, leaves, seeds. Gaseous distress, diarrhea, vomiting, tremors, dyspnea, dilated pupils, respiratory difficulty, weakness, fatigue, collapse, coma, convulsions, bradycardia, circulatory failure, death. Death may be rapid.	Poisoning usually results when branches and trimmings fed to livestock either intentionally or inadvertently.


Poisonous Range Plants of Temperate North America