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University Library, University of Illinois at Urbana-Champaign

Plants Toxic to Animals

N

Narcissus spp. (Daffodil)

Description

Daffodils are ornamental perennial bulbs, common to the United States. The plant grows from bulbs that are various sizes and shapes. The leaves are long and narrow, and the flowers grow either as single flowers or in clusters of up to 20 flowers. They typically don't have a scent, and are either white, yellow, or orange in color.

Distribution

Daffodils are found worldwide.

Conditions of Poisoning

While the entire plant is toxic, the bulbs are particularly toxic. Consuming the bulb may cause vomiting, diarrhea, abdominal pain, and in some cases, cardiac arrhythmia or respiratory depression. 

Control

Keep your pets and animals away from daffodil plants and bulbs so they don't accidentally eat them. If they do, contact your veterinarian immediately. 

Toxic Principle

At least 15 phenanthridine alkaloids including lycorine, have been identified in the leaves, stems and bulbs of Narcissus. The concentrations of the alkaloids are highest in the outer layers of the bulbs.

Clinical Signs

Vomiting, diarrhea, difficulty breathing or swallowing, excess salivation, seizures, dermatitis.

Animals Affected

Dogs, cats, horses, humans

Nerium oleander L. (Oleander)

Description

Oleander is an ornamental evergreen shrub that can grow to approximately 20 feet tall. Its leaves are simple and narrowly lanceoleate, and 3-10 inches long. Its flowers are tubular with five or more petals and are commonly pink, red, purple, or white. The fruit pods contain many seeds, each with a tuft of hair to aid in dispersal.

Distribution

Oleander grows commonly in the wild in the southern portion of the United States from California to Florida, and is also often grown as a cultivated plant in northern climates. It is extensively used in landscaping due to its resistance to drought, heat, wind poor soil conditions, and grazing.

Conditions of Poisoning

All parts of the plant are highly toxic when ingested, and drying does not decrease toxicity. Sap from the plant can cause skin reactions in allergic individuals, and the smoke produced by burning the plant is also toxic. Ingestion is the most common cause of poisoning, and poisoning generally occurs when animals are allowed to graze where oleander is abundantly present. The lethal dose of green oleander leaves for horses and cattle is 0.005% of the total body weight, and the minimum lethal dose for cattle is 50 mg/kg of body weight. Horses that were given 40mg/kg of body weight consistently developed severe gastrointestinal and cardiac signs of poisoning.

Control

Oleander plants can be removed by cutting the branches back and digging out the roots, but full removal may take time as any missed roots will continue to send up new shoots. Oleander is fast growing and tenacious, so any areas where a plant has been removed should be closely monitored for new growth and shoots should be cut back quickly. Caution should be used when pruning or removing oleander plants due to the toxic nature of the sap. Skin should be covered completely while working with the plant, a dust mask is recommended, and cuttings should not be burned.

Toxic Principle

Cardiac glycosides, specifically oleandrin, oleandroside, nerioside, and neriine.

Clinical Signs

Nausea, vomiting, drooling, abdominal pain, diarrhea (possibly bloody)dizziness, slowed or irregular heartbeat, dilation of pupils, drowsiness, death.

Animals Affected

Humans, cattle, horses, dogs, cats, birds

References Used

Knight, A. P., & Walter, R. G. (2001). A guide to plant poisoning of animals in North America. Jackson, Wyo.: Teton NewMedia.

http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=a532

https://plants.ces.ncsu.edu/plants/all/nerium-oleander/

https://www.aspca.org/pet-care/animal-poison-control/toxic-and-non-toxic-plants/oleander

P

Perilla frutescens (Purple Mint)

Description

Purple mint is an annual herb that is sometimes grown ornamentally or to be used as an ingredient in certain dishes. The plant generally grows to be 1-3 feet tall and is erect and often branching. The stem of the plant is usually a burgundy color (though sometimes green) and hairy, and the leaves are simple, opposite, and are green or purple. The edges of the leaves are coarsely serrated, and the leaves can grow to be up to 5 inches wide and 7 inches long, wider at the base and narrowing towards the tip. The flowers are small and vary in color from white to purple, and grow in clusters on flowering branches of the plant.

Distribution

Purple mint is found in the southeastern to midwestern United States. It can grow as a weed in the wild and can pop up anywhere in a pasture, although it prefers semi-shaded locations such as near buildings, the edges of wooded areas, and near fencerows.

Conditions of Poisoning

All parts of the plant are poisonous, but particularly the flowering branches. Dried plants can still be toxic, but the majority of the risk comes from consuming the plant while fresh, especially if flowers or fruit are present. Poisoning is mainly a concern during the late summer and early fall when the plant is flowering and other grasses and forages may be in short supply. Cattle normally do not feed on purple mint unless other food is not available, so it is important to have a ready supply of quality feed on hand for the animals to eat instead during this time of the year, and grazing in infested pastures should be limited during the flowering period.

Control

Effort should be made to look out for and remove the plant in late spring and early summer. It is difficult to control the plant in late summer and early fall, which is also when it becomes the most dangerous to livestock. Plants should be removed before flowering as the flowers are the most toxic part of the plant and to also prevent seed production and dispersal. Mowing the plants before seeds are produced will help prevent further spread as well. Avoid creating feed from areas infested with purple mint.

Toxic Principle

Ketones.

Clinical Signs

Acute pulmonary emphysema, acute respiratory distress syndrome (ARDS), edema, death.

Animals Affected

Cattle, horses, ruminants

References Used

Knight, A. P., & Walter, R. G. (2001). A guide to plant poisoning of animals in North America. Jackson, Wyo.: Teton NewMedia.

https://plants.ces.ncsu.edu/plants/all/perilla-frutescens/

https://extension.tennessee.edu/publications/Documents/W135.pdf

https://www.cfsanappsexternal.fda.gov/scripts/plantox/detail.cfm

Philodendron spp. (Philodendron)

Description

Philodendron plants come in a variety of shapes and sizes depending on the species. Philodendrons commonly have shiny, dark green, deeply lobed leaves that can be several feet long, but that is not true for all species. The popularly cultivated heart leaf philodendron (Philodendron hederaceum) grows as a vine with heart-shaped leaves that are 4-12 inches long depending on the age of the plant and have no lobes.

Distribution

Philodendron plants are natively tropical but are popular indoor plants due to their impressive foliage and low maintenance requirements. Some philodendron species may be seen in the in the wild in the southern United States, but it is more commonly encountered as a cultivated plant.

Conditions of Poisoning

Poisoning occurs after ingestion. All parts of the plant are poisonous, but the leaves have the greatest concentration of the toxin. Skin irritation can also occur after contact with the sap, but is generally minor.

Toxic Principle

Calcium oxalates.

Clinical Signs

Painful burning sensation accompanied by swelling of the lips, tongue, and throat when ingested. Drooling, vomiting (not in horses), difficulty swallowing or speaking, and diarrhea are also possible symptoms. Death can potentially occur from swelling of the windpipe, but is not commonly seen. Skin irritation can occur from contact with the sap.

Animals Affected

Humans, dogs, cats, horses

References Used

https://www.aspca.org/pet-care/animal-poison-control/toxic-and-non-toxic-plants/philodendron-pertusum

https://plants.ces.ncsu.edu/plants/all/philodendron-selloum/

http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=b611

Phytolacca americana L. (Poke or Pokeberry or Pokeweed)
(= P. decandra L.)

Description

Poke is an erect, branched, smooth herb with coarse, succulent, purplish stems; at maturity it is 3 to 10 feet tall. Its leaves, borne on short stalks, are alternately placed and ovate and are without teeth on their margins. Leaves grow up to about 5 inches long. Poke bears small white flowers on short flower stalks along separate branches at the growing tip of the plant and in the axils of the leaves. Each flower becomes a dark purple berry, flattened and spherical. The berries contain crimson juice and about 10 seeds each.

A perennial, poke comes up year after year from an enormous taproot but it is spread only by seed.

Distribution 

Poke is a herbaceous perennial and is native to North America. Though considered as a weed in Illinois, it is a source of food in some regions of the country. Its habitat ranges from the New England states to Florida and as far west as eastern Nebraska. Poke is frequent in open woods and occurs in waste places, along fence rows, about farmsteads, and in pastures if the soil is especially moist and rich.

Conditions of Poisoning

Cattle and sheep are the most susceptible species but poisoning occasionally occurs in horses, goats, and pigs. Animals may feed on poke plants, especially in the spring, when the plants are succulent. Where grass is short, the animals may browse so close as to get the top parts of the poke roots. Unless green herbage is very scarce later in the summer, animals will avoid the tops and berries.

Control

Animals should not be grazed in pastures infested with poke, especially in the spring or during dry, hot periods. The most certain way to eliminate poke from wooded pastures, where the plants are likely to be numerous and where it may be difficult or impossible to use chemical weed-killers, is to dig the individual plants out by their roots. As poke is spread only by seed, it is important to destroy the plant before flowering. 

Toxic Principle
  • Saponins, believed to be the primary toxic constituents, are present in the berry juice and other parts.
  • Other toxic constituents have also been identified including the alkaloid phytolaccine (in small amounts) and the alkaloid phytolaccotoxin, as well as a glycoprotein.
  • If used as food, the water in which it is boiled must be thrown away. 
Clinical Signs

The eating of nonfatal quantities of poke, perhaps of the shoots, may cause retching or vomiting after two hours or more. These signs may be followed by dyspnea, perspiration, spasms, severe purging, prostration, tremors, watery diarrhea (often bloody) and, sometimes, convulsions. If a fatal quantity is eaten, perhaps including roots, the above signs are followed by paralysis of the respiratory organs and other narcotic effects, culminating in the death of the poisoned animal.

In Pigs:

  • Unsteadiness, inability to rise, retching.
  • Jerking movements of the legs.
  • Subnormal temperature.

In Cattle:

  • Same general signs plus a decrease in milk production. 
Animals Affected

Cattle, swine

Podophyllum peltatum L. (Mayapple)

Description 

Mayapple is a perennial herb of the Barberry family. Leaves are umbrella-shaped and are about 8 inches wide with 5-9 lobes. Plants that have a single leaf do not flower, while those with two leaves develop a single flower in the axil of the leaf stalks. The flower appears at the end of the downward-curved flower stalk about 1 inch long. The flower, with 6 or more white petals and about 1.5-2 inches across, blooms in April to May, and is eventually replaced by a green ovoid fruit. The plant withers away by mid-summer.

Although the creeping, fleshy rhizome has been used to prepare medicine commercially, it is poisonous by contact. The green leaves and unripened fruit are poisonous but the fruit becomes edible as it ripens and turns greenish-yellow in color. 

Distribution

Mayapple is found throughout the eastern and midwestern states of the U.S., from New York to Georgia and as far west as eastern Kansas and northeastern Oklahoma. Mayapple grows in colonies in damp meadows, woodlands, pastures, and along roadsides, and is a familiar spring woodland plant in all counties of Illinois. 

Conditions of Poisoning

Poisoning of livestock occurs primarily in the spring, but the plant is usually avoided and seldom eaten in harmful amounts by livestock. The root is the most toxic part and handling of it may cause dermatitis or other skin problems in humans. 

Toxic Principle

The toxic principles include the bitter resinous substance podophyllin, which is extractable with alcohol and precipitated in water. Podophyllin is actually a mixture of at least 16 physiologically active compounds, which are divisible into two groups, the lignans and flavonols. One of the active lignans is podophyllotoxin.

Clinical Signs

General signs include purgation, catharsis, and other signs referable to gastroenteritis.

Affected cattle may show the following signs: hypersalivation, anorexia, lacrimation, diarrhea, and excitation which lasts about 1 day. The muzzle and intermandibular area as well as the eyelids may become swollen.

When swine consume mayapple shoots or leaves, death may occur after few signs.

Experimental studies with a podophyllotoxin from a plant in the same family, also termed mayapple, show evidence of degenerative changes in the liver, intestine, testis and pancreas in orally exposed animals. 

Animals Affected

Cattle, swine, dogs, cats

Pteridium aquilinum (Bracken Fern or Brake Fern)

Description 

Bracken fern is a typical fern. Its large triangular fronds are divided into three main parts with each part bipinnately subdivided. These fronds are 2 to 4 feet long by 1 to 3 feet wide. They are borne at the tips of erect, rigid, straw-colored, smooth stalks 1 to 3 feet tall. The stalks rise at intervals from stout black underground rootstocks sometimes a yard or more long.

Spores are borne in late summer at the edges on the lower sides of mature fronds, and the edges fold under to form the spore cover. The rootstocks also spread the fern.

Distribution

Many varieties of bracken fern are found throughout the U.S., particularly in dry pastures and meadows, abandoned fields, and open woods on sandy and gravelly soil. In Illinois it may be a pest throughout the northern third of the state.

Even when there is no bracken fern in the open pastures, it may be growing in the fencerows and along roadsides, where animals may browse it when other forage is scarce.

Conditions of Poisoning

In dry, hot seasons or in late summer to early fall, when succulent herbage is scarce, animals more often eat bracken, although they generally avoid it at other times. Also, if hay is cut from bracken fern-infested meadows and fed, poisoning may result. Both cattle and horses are susceptible to bracken fern poisoning. Sheep and swine rarely eat bracken fern, but exposed swine (at least) may sometimes experience a thiaminase-mediated syndrome.

Control

Especially during dry periods, animals should be kept out of bracken fern-infested pastures. Hay from infested meadows should not be used for feed or bedding. Generally bracken fern should be eliminated from pastures and hayfields. Large infestations of bracken fern may be reduced gradually by pulling or mowing the fronds twice a year (in June and August) or by fertilizing and liming infested areas. 

Toxic Principle 

Thiaminase from bracken fern especially affects horses and pigs but not cattle. Ptaquiloside affects cattle and sheep and causes bone marrow damage. Other toxic principles that affect cattle are: aplastic anemia factor, and hematuria causing factor. 

Clinical Signs

Bracken fern poisoning affects the cow and the horse differently with regard to both clinical signs of illness and tissue damage. Consumption of the plant may also affect the flavor and odor of the milk produced by the animal.

In cattle:

After feeding on bracken fern for several to many days, cattle often sicken rather suddenly and, contrary to their reaction to most types of plant poisoning, they may show a very high fever. Major effects of bracken fern poisoning in cattle are related to damage to the blood forming elements (decreases production of white blood cells, red blood cells, and platelets) and sometimes to urinary tract carcinogenesis. Clinical signs may include rapid loss of body weight, difficult breathing, excessive salivation, bleeding from the nose, blood in the droppings, and congested, hemorrhagic, or icteric (jaundiced or yellowish) mucous membranes may also be observed. Bracken fern poisoning has been mistaken for anthrax and other infectious diseases of cattle.

In horses:

The first clinical signs of bracken fern poisoning in horses are usually an unsteady gait, a "tucked up" appearance of the flanks, nervousness, timidity, congestion of the visible mucous membranes, and constipation. Later, the horse may stand with legs spread, walking with a staggering gait, and occasionally fall, especially if its head is raised suddenly. The appetite may remain normal. Dilated pupils and both increased and decreased heart action have been reported in cases of equine bracken fern poisoning. If not treated, death occurs in 2-10 days, though some horses occasionally survive up to 30 days or more after onset of poisoning.

Animals Affected

Horse, cattle, sheep, swine

References Used

Knight, A. P., & Walter, R. G. (2001). A guide to plant poisoning of animals in North America. Jackson, Wyo.: Teton NewMedia.

R

Ranunculus spp. (Buttercup)

Description

The small-flowered buttercup is an erect, often widely branched smooth herb with a hollow stem. It grows 6 inches to 2 feet tall. It has two kinds of leaves: petioled basal leaves that are roundish and have scalloped edges, and alternately placed stem leaves that are stalkless, deeply divided, and made up of about 5 narrow lobes, often 3-pointed. Its flowers are yellow, are 1/4 inch wide or less, and have 5 petals, which are shorter than the 5 green sepals. After the flowers wither, numerous seeds form globose heads at the tops of the flower stalks.

The cursed buttercup (Ranunculus sceleratus L.) is similar to the small-flowered buttercup but has divided basal leaves. Its stems are hollow. The hooked buttercup (Ranunculus recurvatus Poir.), so-named because of its hook-tipped seeds, has long yellow petals that form a flower 1 inch wide. The swamp buttercup (R. septentrionalis Poir.) has 3-lobed leaves and bright-yellow flowers 1 inch or more wide. 

Distribution

The buttercups named above occur as frequent to common plants throughout the state. The small-flowered buttercup, often a troublesome weed, may be found in any location that is not very sandy or wet. The cursed buttercup is limited to the northern third of the state, where it may be abundant in ditches and springy places as well as in ponds. The swamp buttercup grows in wet woods everywhere in the state.

Several other kinds of buttercups, less abundant or less widely distributed, may be seen in other habitats or from place to place. The tall buttercup (Ranunculus acris L.), to which poisoning of stock is commonly attributed, occurs in northern and central Illinois as a plant introduced locally along highways and railroads. 

Conditions of Poisoning

Buttercups generally inhabit moist areas. Animals allowed to graze in woods, in wet meadows, and by ditches and streams browse the buttercups with other succulent plants. All animals are susceptible to buttercup poisoning, but cows are most often poisoned. Dried buttercups, however, are not poisonous; therefore animals can be fed buttercup-infested hay without danger. 

Control

Animals should not be grazed in pastures heavily infested with buttercups, especially when other herbage is scant or dry. Buttercups are hard to destroy because of their tendency to inhabit moist and wet places. Mowing the plants each year before they produce seed will tend to keep them from increasing and may eventually destroy them. 

Toxic Principle

Ranunculus spp. contain the glycoside, ranunculin from which the poisonous principle, protoanemonin is released when the plant is crushed by virtue of enzymatic action which is activated by crushing. Protoanemonin is a volatile, yellow oil with a lactone moiety which is extremely prone to undergo spontaneous polymerization to yield the innocuous anemonin. Protoanemonin is a bitter tasting oil. 

Clinical Signs

Buttercup poisoning causes cows to give less milk and may cause the milk to be bitter and red tinted. Severe poisoning brings on colic and diarrhea, with black foul-odored feces, nervousness, twitching of the ears and lips, difficult breathing, and eventually convulsions. The symptoms shown by horses and sheep are similar, but poisoned sheep are likely to fall suddenly. Pigs suspected of tall-buttercup poisoning have shown paralysis but not much digestive disorder. 

Animals Affected

Cattle, goats, horses

Rheum rhaponticum (Rhubarb)

Description

Rhubarb is a perennial herb that is generally kept as a cultivated plant for use as a food item or as an ornamental plant either indoors or in a landscape. The leaves of the plant are large and heart-shaped with a thick, reddish petiole. Flowers are green to white, small, and grow in a dense panicle on the end of a flowering stem. Fruits are winged and reddish-brown when mature. Roots are large and fleshy.

Distribution

As a domestic plant, rhubarb is found all across the United States in homes, gardens, farms, and landscapes. Rhubarb is sometimes found in the wild as an escaped plant, and prefers moist, fertile soils.

Conditions of Poisoning

The toxin is transmitted through consumption of the leaves of the plant. The leaves are toxic when raw and the leaf blade remains toxic even after cooking and should never be eaten. The leaf stem contains less of the toxin and is generally safe to eat after being cooked, although consuming very large amounts (multiple pounds) of the cooked stems can cause symptoms of poisoning. Cooking the rhubarb with calcium carbonate will also help neutralize the toxin by converting the soluble calcium oxalates to insoluble calcium oxalates.

Toxic Principle

Soluble calcium oxalates.

Clinical Signs

Kidney failure, tremors, salivation, abdominal cramps, burning sensation in mouth and throat, headache, weakness, nausea, vomiting, coma and death if large quantities eaten.

Animals Affected

Humans, livestock, dogs, cats, horses

References Used

Knight, A. P., & Walter, R. G. (2001). A guide to plant poisoning of animals in North America. Jackson, Wyo.: Teton NewMedia.

https://www.aspca.org/pet-care/animal-poison-control/toxic-and-non-toxic-plants/rhubarb

Rhododendron spp. (Rhododendron)

Description

Rhododendron is a genus of a shrub with about 800 species worldwide. Its ovate evergreen or deciduous leaves are alternate, 1/2 - 8 inches in length depending on variety, with smooth untoothed margins. They are dark green with a glossy upper surface and a dull underside. Large trusses of bell-shaped flowers bloom from spring to early summer. Plants are available with flowers in colors such as white, purple, deep rose, red, yellow, and orange. Rhododendron and the closely related azalea have been hybridized for many uses in gardens and rarely reach above 3-5 feet tall in northern states including Illinois. 

Distribution

In Illinois, most species found are ornamental types that usually thrive in protected areas of gardens. Tall, wild varieties can reach over 35 feet high, and are found throughout the coastal mountain ranges from New York to Georgia. Designated as West Virginia's state flower, rhododendrons are particularly abundant in the Great Smoky and the Blue Ridge mountains. Species in the Pacific northwest from northern California to British Columbia vary in heights. 

Conditions of Poisoning

All parts of the plant, but especially the foliage, contain the poison, and consuming two or three leaves may produce severe toxicosis. Sucking flowers free of nectar may produce serious illness. Rhododendrons are more likely to retain green leaves year round than are most other plants, and therefore most cases of poisoning occur in the winter and early spring, when other forage is unavailable. 

Toxic Principle

All parts of this plant contain toxic resins (andromedotoxins, now commonly referred to as grayanotoxin) with the leaves being the most potent. Grayanotoxin produces gastrointestinal irritation with some hemorrhage, secondary aspiration pneumonia, and sometimes renal tubular damage and mild liver degeneration. 

Clinical Signs

Clinical signs usually appear within 6 hours of ingestion. Affected animals may experience anorexia, depression, acute digestive upset, hypersalivation, nasal discharge, epiphora, projectile vomiting, frequent defecation, and repeated attempts to swallow. There also may be weakness, incoordination, paralysis of the limbs, stupor, and depression. Aspiration of vomit is common in ruminants and results in dyspnea and often death. Pupillary reflexes may be absent. Coma precedes death. Animals may remain sick for more than 2 days and gradually recover.

Animals Affected

Dogs, cats, horses, cattle, sheep, goats, humans (from consumption of the plant, rhododendron tea, and/or honey made from rhododendron pollen).

References Used

Knight, A. P., & Walter, R. G. (2001). A guide to plant poisoning of animals in North America. Jackson, Wyo.: Teton NewMedia.

https://www.aspca.org/pet-care/animal-poison-control/toxic-and-non-toxic-plants/rhododendron

https://csuvth.colostate.edu/poisonous_plants/Plants/Details/111

Ricinus communis (Castor Bean)

Description

Castor bean is a herbaceous annual which can reach to nearly 15 feet tall when growing in open spaces in warm climates. Large leaves are alternate, palmately lobed with 5-11 toothed lobes. Leaves are glossy and often red or bronze tinted when young. Flowers appear in clusters at the end of the main stem in late summer. The fruit consists of an oblong spiny pod which contains three seeds on average. Seeds are oval and light brown, mottled or streaked with light and dark brown and resemble a pinto bean. The plant itself is fast growing, but the seeds require a long frost-free season in order to mature. 

Distribution

Castor bean is native to the tropics (Africa) but is planted as a garden plant throughout the U.S. for its large, striking appearance. It is now commerically grown in the U.S. in Illinois, Missouri, Kansas, Oklahoma, Oregon and California. As a result, it is naturalized in the south where winters are mild and most often is found near streambeds, dumping grounds, barnyards or along roadsides.

Conditions of Poisoning

All parts of the plants are toxic, but most dangerous are the seeds. The most susceptible animal species include cattle, horses, sheep, pigs, fowl, rabbits and other small animals. Seeds ingested at 0.2% of body weight have caused toxicosis in cattle and 0.01% of body weight was toxic to horses.

Control

Castor bean plants are grown largely as commercial and garden plants, and should not be planted in or near livestock enclosures. Plants may appear in the wild in areas of the south where the plant has become naturalized, and animals should not be allowed to graze in areas where the plant grows.

Toxic Principle

The principle toxin of castor bean is ricin which is a lectin, also termed a toxalbumin. Ricin may comprise up to 3% of the seed weight. Toxalbumins are very toxic plant-derived compounds that combine carbohydrate and protein moieties or components. Ricin is water soluble and is not present in castor oil. Taken orally, ricin is readily absorbed from the stomach and intestine. Another phytotoxin in castor bean, ricinine, is reportedly goitrogenic, but the significance of this compound is not clearly established.

Clinical Signs

Signs appear after a characteristic lag period of a few hours to days, usually between 12 hours and 48 hours. Signs support nausea and include evidence of abdominal pain, bloody diarrhea, tenesmus, and dehydration. Additional signs may be anorexia, cessation of rumination, excessive thirst, weakness, muscle twitching, dullness of vision, convulsions, dyspnea, opisthotonus and coma. At postmortem severe inflammation of the stomach and intestine are evident.

Sometimes convulsions and decreased tendon reflexes are observed. After convulsions, death may result from paralysis of the respiratory center. Artifical respiration may not preserve life for long because of rapid onset of concurrent vasomotor paralysis.

In ducks, there is an ascending paralysis which may be confused with botulism. Sometimes thousands of ducks as well as geese are poisoned.

For horses, signs include trembling, sweating, dyspnea, incoordination, vigorous heart contractions, shivering, cold extremities, depression, increased body temperature, weak pulse, constipation or diarrhea, and convulsions.

Cattle may have diarrhea stained with blood.

Pigs have frequent vomiting.

Poultry show signs of depression, roughened feathers, droopy wings, greyish wattles and combs, and emaciation. Egg production ceases and premature moulting may begin.

Animals Affected

Ducks, horses, cattle, pigs, poultry