EKAHA

EKAHA Identification Guide:Toxic Plants Compiled By:Charlie Armour

Poisonous Plants Black Locust (Robinia pseudoacacia 1 Bracken Fern (Pteridiu m aquliinium) 2 Buckwheat (Fagopyrum esculentum) 2 Castor Bean (Ricinus communis) 3 Cherries(Wild):Black Cherry, Bitter Cherry, Choke Cherry, Pin Cherry (Prunus) 4 Clover (Trifolium spp.) 5 Sweet Clover (Melilotus alba spp.) 6 Fiddleneck (Amsinckia intermedia) 7 Groundsels, Senecio, and Ragworts (Senecio spp.) 8 Horsetail (Equisetum arvense spp.) 9 Jimsonweed (Datura stromonium) 9 Locoweed (Astragalus and Oxytropis spp.) 10 Climbing Nightshade, Black Nightshade, Potato (Solanum spp.) 11 Oaks (Quercus spp.) Red Oak, White Oak, and Black Oak 11 Red Maple (Acer rubrum) 12 Rhubarb (Rheum rhaponticum) 13 Russian Knapweed, Yellow-Star Thistle 13 St. John's Wort (Hypericum perforatum) 14 Sensitive Fern (Onoclea sensibis) 15 Sorghum or Milo, Sudan Grass, and Johnson Grass ((sorghum spp. 16 Yew (Taxus spp.)52 Schrubs, Flowers and Trees Known to be Safe 17 Toxic Plants

Toxic Plants can be found in most, if not all, pastures. It should be our responsibility as horse owners to be able to identify the plants that may harm our horses and also the symptoms related to each. Early recognition of the symptoms can mean the difference in saving your horses life. There is good news, too. These plants are rarely the horses' first choice as forage. Due to the bitter taste and generally unpalatable textures, horses rarely ingest these plants. However, even the best pastures may harbor these potential killers and horses may inadvertently eat them, so be prepared. NOTE: While many of these plants have no treatments listed in the literature, if you suspect poisoning of your horse, you should immediately call your veterinarian for definitive diagnosis and possible treatment. Schrubs, Flowers and Trees Known to be Safe 17 Toxic Plants

Toxic Plants can be found in most, if not all, pastures. It should 1

be our responsibility as horse owners to be able to identify the plants that may harm our horses and also the symptoms related to each. Early recognition of the symptoms can mean the difference in saving your horses life. There is good news, too. These plants are rarely the horses' first choice as forage. Due to the bitter taste and generally unpalatable textures, horses rarely ingest these plants. However, even the best pastures may harbor these potential killers and horses may inadvertently eat them, so be prepared. NOTE: While many of these plants have no treatments listed in the literature, if you suspect poisoning of your horse, you should immediately call your veterinarian for definitive diagnosis and possible treatment.

Black Locust (Robinia pseudoacacia) The seeds, bark, and leaves contain toxic proteins that have caused sickness and death in horses. The plant should be considered toxic to all animals if eaten. This tree can be found around older farms and houses and is also planted along fence rows. If older trees are cut down in areas where horses have access, make sure they do not eat any sprout (sucker) growth that may emerge from the stump. Nomenclature Botanical name Robinia pseudoacacia English Common name: Black Locust Botanical family name: Leguminosae English family name: pea Toxic parts: bark, leaves, seeds Toxic chemicals: Robin (or robinin) and phasin, which are toxic proteins called toxalbumins, are present in black locust. A glycoprotein that clumps red blood cells has been extracted from the plant. It is not clear if this is robin or another substance. Experimental feeding to horses has shown the following toxicity: => aqueous extract of bark about 0.1% of body weight caused symptoms => powdered bark about 0.04% of body weight caused symptoms General symptoms of poisoning: Horses that have eaten black locust leaves, sprouts, and bark were poisoned and died. Symptoms include loss of appetite (anorexia), weakness, paralysis of the hindquarters, nausea and coldness of the extremities. Symptoms of colic also occur. In severe cases, death may occur. Bracken Fern (Pteridiu m aquilinium) Bracken is a native fern. Horses have been poisoned after eating bracken. Bracken contains several chemicals that cause problems. Thiaminase results in vitamin B1 deficiency in nonruminants such as horses. Ptaquiloside, a carcinogen-mutagen, causes acute and chronic symptoms of illness in ruminants (cows). The spores may contain carcinogens that can cause problems to animals as well. The young fronds of bracken contain significant quantities of the carcinogen. Nomenclature 2

Botanical name Pteridium aquilinium English Common name: bracken Botanical family name: Polypodiaceae English family name: fern Toxic parts: all parts including leaves, rhizomes, spores and young shoots Toxic chemicals: thiaminase, ptaquiloside, prunasin and aqualide A General symptoms of poisoning: Symptoms can include loss of appetite, convulsions, colic, coffee-colored urine, lack of oxygen in the blood (cyanosis - characterized bya bluish or purplish discoloration of the skin or mucous membranes), stiff gait, a tendency to lay down, low red blood cell count (anemia), and death. Buckwheat (Fagopyrum esculentum) Buckwheat is cultivated as a crop for fodder and for the production of buckwheat honey. Eating entire plants, dried or fresh, has caused sensitivity to light in horses with exposed light-colored skin. Exposure to the sun is necessary. This plant is considered to be a primary photosensitizer, although jaundice has occurred at the same time, which indicates secondary involvement of the liver. Exposure may cause various allergic and non-allergic reactions including asthma, skin disorders, fever reactions, and airway obstruction and inflammation. Nomenclature Botanical name: Fagopyrum esculentum English Common name: buckwheat Botanical family name: Polygonaceae English family name: buckwheat Toxic parts: all parts Toxic chemicals: Fagopyrin, probably a derivative of naphthodianthrone, is closely related to hypericin, which is found in St. John's-wort. The absorption spectra of these chemicals is in the range of 540-610 nm General symptoms of poisoning: loss of appetite, staggering gait, peeling of the skin and thirst.

Castor Bean (Ricinus communis) The seeds from the castor bean plant are poisonous to people, animals and insects. One of the main toxins is ricin. Also present is RCA (Ricinus communis agglutinin). Ricin is a potent cytotoxin but a weak hemagglutinin, whereas RCA is a weak cytotoxin and a powerful hemagglutinin. Poisoning by eating of the castor bean is due to ricin, not RCA, because RCA does not penetrate the intestinal wall, and does not affect red blood cells unless given intravenously. If RCA is injected into the blood, it will cause red blood cells to burst. Castor beans are used as an ingredient in some animal feeds after the oil has been extracted or inactivated by heating for 20 minutes at 140oC. Attempts to use castor beans in feed for horses involve different methods of inactivating ricin while maintaining nutritional value. Some studies have shown that even after such heat treatment toxicity remains. Poisoning of livestock usually occurs by accidental incorporation of castor beans in their feed. Horses are 3

particularly vulnerable. Nomenclature Botanical name Ricinus communis English Common name: castor bean Botanical family name: Euphorbiaceae English family name: spurge Toxic parts: seeds Toxic chemicals: Ricin, RCA (Ricinus communis agglutinin) General symptoms of poisoning: The accidental addition of castor beans into grain given to horses can cause sweating, rocking gait, rapid pulse, muscle spasms, high temperature, and abdominal pain. The early symptoms may be confused with respiratory infection. Cherries (Wild): Black Cherry, Bitter Cherry, Choke Cherry, and Pin Cherry (Prunus) Chokecherry is a native plant that appears as a shrub or small tree. Horses have been poisoned and have died after eating large quantities of berries, which contain the seeds. Eating the plant material can poison all types of livestock. (Related species, including peach (Prunus persica) and apricot (Prunus armeniaca), have pits with enough toxin to cause poisoning and death in humans and animals. Pin cherry (Prunus pensylvanica) is a native tree that can be found throughout most of the US. The leaves have an average nitrogen rate of 91 mg/100 g, with as much as 143 mg/100 g recorded. These levels are potentially lethal to horses if eaten. At all stages of growth, leaves of red chokecherry contain quantities of prunasin that are well above the minimum 1.4% level required for acute poisoning. Twigs also contain levels of prunasin at or above the level required to cause acute poisoning. Twigs developed more toxin during dry years. The prunasin level of buds and flowers is above the minimum level as well. Nomenclature Botanical name: Prunus Virginiana L., Prunus pensylvanica L. f, Prunus serotina English Common name: red Chokecherry, Pin cherry, Black Cherry Botanical family name: Rosaceae English family name: rose Toxic parts: leaves, berries, pits, twigs, buds, flowers Toxic chemicals: amygdalin, prunasin. General symptoms of poisoning: Eating as little as .25% of body weight of plant material can lead to coma, convulsions, lack of oxygen in blood, and death by asphysiation. Additionally, you may see staggering gait or extreme agitation. Drawn blood is usually bright red. Onset of symptoms is often sudden and acute. Clover (Trifolium, spp.) Cases of sensitivity to light have occurred from eating this feed plant, sometimes accompanied by liver enlargement and damage. All toxic compounds have not been identified, although nitrate poisoning is one likely suspect. Eating red and white clover plants can cause bloat, infertility and conditions known as 'congenital joint laxity' and 'dwarfism' in foals. White clover has caused laminitis in horses. After the plants are eaten, some varieties can liberate HCN, causing cyanogenic poisoning in animals. White clover is also reported to 4

cause birth defects if infected with various fungi. Nomenclature Botanical name: Trifolium spp. English Common name: clover (alsike, red, white) Botanical family name: Leguminosae English family name: pea Toxic parts: All parts Toxic chemicals: nitrate, isoflavones, Two cyanogenic glycosides, linamarin and lotaustralin, are found in white clover. In young leaves, the cyanogen levels may reach 350 mg of HCN per 100 g of tissue. Two independently inherited genes in white clover control cyanogenesis. Only plants possessing at least one dominant functional allele of both genes liberate HCN when damaged. General symptoms of poisoning: depression, staggering gait, blindness, liver disease (cirrhosis), severe degeneration of the kidneys, infertility, laminitis (tenderness, swelling, and inflammation around the hooves). Sweet Clover (Melilotus alba spp.) White sweet-clover is a cultivated and naturalized plant that occurs as a weed. This plant contains a glycoside with a coumarin fraction. When sweet-clover is harvested for feed, the succulent stems usually mold before drying. The molds metabolize the glycoside into dicoumarol, which interrupts vitamin K activation of prothrombin, necessary in blood clotting. Levels of dicoumarol at more than 10 ppm are suspected of possible poisoning. Dicoumarol levels are usually higher in small and round bales than in stacks. Nomenclature Botanical name Melilotus Alba Desr., English Common name: White Sweet Clover, Yellow Sweet Clover Botanical family name: Leguminosae English family name: pea Toxic parts: leaves and stems. Moldy sweet-clover is produced through insufficient drying of bales and silage. Dicoumarol production by molds is not likely to occur if animals ingest living plants. Toxic chemicals: dicoumarol, melilotoside General symptoms of poisoning: Eating moldy sweet clover forage can lead to low red blood cell count, swelling and hemorrhage. Treatment is possible with whole blood transfusion and injections of 4.2 g of menadione sodium bisulphate. Vitamin K1 is also effective in treatment. Fiddleneck (Amsinckia intermedia) An introduced plant found mainly in California and the Pacific Northwest. Eating fiddleneck can cause severe diseases in horses. Liver damage results from eating the seeds of the plant. The symptoms are known as 'walking disease' in horses.

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Nomenclature Botanical name: Amsinckia intermedia English Common name: fiddleneck Botanical family name: Boraginaceae English family name: borage Toxic parts: seeds Toxic chemicals: intermedine, lycopsamine, echiumine, The pyrrolizidine alkaloids of fiddleneck cause liver damage in horses, mainly a result of the presence of the seeds in grain and grain screenings fed to livestock. General symptoms of poisoning: The presence of blood in the urine, continous aimless walking, extreme nervousness, liver damage, death.

Groundsels, Senecio, and Ragworts (Senecio spp.) Entire-leaved groundsel (Senecio integerrimus) is a native herb. This plant has caused poisoning of horses. Eating the plant material over long periods causes irreversible liver damage. This plant grows when other forage is abundant so that it is not a toxic threat unless forage is scarce or the plant is abundant in an area to be cut for hay. Tansy ragwort contains pyrrolizidine alkaloids that primarily cause irreversible liver damage. Tansy ragwort should be eradicated from forage and crops. Animals may be poisoned if they drink the milk of other animals that have eaten this plant, i.e., foals. Horses may stagger, press their head against objects, and walk in a straight line regardless of obstructions. Nomenclature Botanical name Senecio integerrimus,Senecio jacobaea, Senecio vulgaris English Common name: entire-leaved groundsel, tansy ragwort, common groundsel Botanical family name: Compositae English family name: Composite Toxic parts: All parts Toxic chemicals: Toxic agent unknown in groundsels. Pyrrolizidine alkaloids are found in other toxic members of the genus Senecio and are probably the chemicals responsible for cases of poisoning found in experiments. Pyrrolizidine alkaloids such as jacobine and seneciphylline are found in tansy ragwort. The content of these alkaloids has been measured at a mean level of 0.31%. General symptoms of poisoning: confusion, restlessness, weakness, depression, abdominal swelling, peeling of skin, weight loss, coma, yellowish discoloration of the skin and mucous membranes (jaundice) and liver damage leading to death. Eating plant material causes jaundice, a sweet odor from the skin and, after 1 or 2 days, insensibility to objects and pushing against obstacles, urine discoloration, and death. All horses that showed definite symptoms died. Liver damage was apparent upon postmortem examination. Horsetail (Equisetum arvense spp.) Field horsetail is a native plant. This plant contains thiaminase, 6

which causes thiamine deficiency in horses. Eating the leaves and stems of field horsetail has poisoned horses.

Nomenclature Botanical name Equisetum arvense English Common name: field horsetail Botanical family name: Equisetaceae English family name: horsetail Toxic parts: leaves and stems Toxic chemicals: Thiaminase is an enzyme that splits thiamine, a B vitamin, making it inactive. Thiamine is involved in decarboxylation reactions in animal bodies. Deficiency of thiamine leads to accumulation of pyruvate in the blood, with a resulting impairment in energy metabolism and cellular shortage of ATP. Hay that contains horsetail at a level of 20% or more may produce symptoms of thiamine deficiency in horses in 2-5 weeks. General symptoms of poisoning: Symptoms can include loss of appetite, inability to coordinate voluntary muscle movement (ataxia), colic, stiff gait, a tendency to lay down and low red blood cell count. Severe cases can lead to convulsions and death. Jimsonweed (Datura stromonium) Poisoning can occur when hungry animals are on sparse pasture with Jimsonweed infestation. Most animal poisoning results from feed contamination. Jimsonweed can be harvested with hay or silage, and subsequently poisoning occurs upon feeding the forage. Nomenclature Botanical name Datura stromonium English Common name: Jimsonweed Botanical family name: English family name: Jimsonweed Toxic parts: All parts of Jimsonweed are poisonous. Leaves and seeds are the usual source of poisoning, but are rarely eaten do to its strong odor and unpleasant taste. Toxic chemicals: Jimsonweed toxicity is caused by tropane alkaloids. The total alkaloid content in the plant can be as high as 0.7%. The toxic chemicals are atropine, hyoscine (also called scopolamine), and hyoscyamine. General symptoms of poisoning:. Early Signs rapid pulse restlessness frequent urination rapid breathing nervousness diarrhea dilated pupils muscular twitching weight loss depression loss of appetite Fatal Cases weak pulse irregular breathing coma 7

lower body temperature retention of urine convulsions

Locoweed (Astragalus and Oxytropis spp.) Eating the plant causes a variety of problems. Plants contain the alkaloid swainsonine, which can cause 'locoism'. The common symptoms are: impairment of the nervous and immune systems, depression, dullness or excitement when disturbed. Abortion and birth deformities may occur. Animals may become habituated to locoweed. Swainsonine influences the vascular system and can cause heart failure. This is a major poisonous range plant in the western United States. Nomenclature Botanical name: Astragalus lentiginosus, Oxytropis lamberti English Common name: Astragalus, purple locoweed Botanical family name: Leguminosae English family name: pea Toxic parts: flowers, leaves, seeds, stems. The flowers of locoweeds contain more swainsonine than the leaves. The immature pods contain less swainsonine than the blooms, but this amount increases with maturity. Toxic chemicals: swainsonine, slaframine. Swainsonine, the chemical involved in locoism, is found in several plants, including Astragalus bisulcatus, A. lentiginosus, Oxytropis lambertii, and O. sericea. This indolizidine alkaloid causes locoism in horses; it also causes birth defect deformities in foals. General symptoms of poisoning: depression, excitement when disturbed, impaired nervous system function, abdominal swelling, loss of appetite, generalized swelling, lack of coordination, may lead to paralysis and death. Climbing Nightshade, Black Nightshade, Potato (Solanum spp.) Nightshade is a naturalized woody vine, sometimes grown as an ornamental. The plant, especially in its green immature fruits, contains steroidal alkaloids, which have caused poisoning in horses. Potatoes are also in the nightshade family, containing the same toxins. Most potato plants have been tested for lowered levels of the toxins, and are generally safe. If a horse were to injest the berries of the potato plant, however, toxic response should be expected.

Nomenclature Botanical name Solanum dulcamara, Solanum nigrum, Solanum tuberosum English Common name: Climbing nightshade, Black nightshade, Potato Botanical family name: Solanaceae English family name: nightshade Toxic parts: immature fruit, leaves Toxic chemicals: Immature green berries of climbing nightshade 8

contain parent steroidal alkaloid aglycones: 50% solasodine and 50% of another aglycone thought to be soladulcidine. The total alkaloid concentration has been found to be 0.030% of dry matter in the green berries. Two glycoalkaloids, alpha-solanine and alpha-chaconine, are the major alkaloids in potatoes. The major effects are gastrointestinal tract irritation and nervous system impairment. Exposing potato tubers to light may increase the concentration of glycoalkaloids to 0.05% in the tuber instead of the usual 0.008%. General symptoms of poisoning: eating of the immature fruits can lead to rapid respiration, feeble pulse, high temperature, dilated pupils, then death. Oaks (Quercus spp.) Red Oak, White Oak and Black Oak

Eating of acorns of any species of Oak can cause severe poisoning in horses. The tannin compounds present in the acorns are present also in the leaves, though to a lesser extent.

Nomenclature Botanical name Quercus alba, Quercus rubra Quercus velutina English Common name: white oak, red oak, black oak Botanical family name: Fagaceae English family name: beech Toxic parts: acorns and leaves Toxic chemicals: The toxic agents are polyhydroxyphenolic compounds (tannins) including gallic acid, pyrogallol, and tannic acid. The concentration of these compounds is higher in immature, green acorns than in mature ones. The following quantities of phenolics were found in acorns: Oak species Total phenolics (% of total weight) Quercus alba (white oak) 1.09 (0.41-2.54) Quercus rubra (red oak) 3.72 Quercus velutina (black oak) 4.51 (3.29-6.13) Black oak and red oak contain a greater total average of phenolics in acorns than white oak. General symptoms of poisoning: Eating the leaves and acorns can cause toxic symptoms including loss of appetite, bloody diarrhea, constipation, swelling, dehydration, leading to death. Red maple (Acer rubrum) Horses can be poisoned after they eat wilted red maple leaves. Signs of poisoning are similar to those seen with the Brassica anemia factor after animals ingest of plants of the genus (such as canola, kale and cabbage).

Nomenclature Botanical name Acer rubrum 9

English Common name: Red maple Botanical family name: Aceraceae English family name: maple Toxic parts: Eating of wilted leaves of red maple have caused poisoning and death in horses. This toxicity is most prevalent from June through October. Cases become symptomatic 3-4 days after eating the leaves. Wilted leaves administered to a pony at the rate of 3.0 g/kg of body weight caused illness and death within 1-5 days. Freshly harvested leaves did not cause any symptoms. Dried leaves remain toxic for up to 30 days. Toxic chemicals: toxic agent unknown General symptoms of poisoning: rapid breathing, lack of oxygen in blood, dehydration, depression, elevated heart rate, congested lungs, swelling of kidneys, brown mucous membranes, brownish urine, brownish blood, weakness, leading to coma and death. Rhubarb (Rheum rhaponticum) Rhubarb (Rheum rhaponticum) is a perennial cultivated plant. The plant contains oxalate crystals, which have been reported to cause poisoning when large quantities of raw or cooked leaves are eaten. Anthraquinones (glycosides) have been implicated more recently in poisoning. The stalks are widely used as preserves and are also eaten raw, without problems. The toxic content is much lower in the stalks than the leaves. Nomenclature Botanical name Rheum rhaponticum English Common name: Rhubarb Botanical family name: Polygonaceae English family name: Buckwheat Toxic parts: leaves Toxic chemicals: Oxalates are contained in all parts of rhubarb plants, especially in the green leaves. There is some evidence that anthraquinone glycosides are also present and may be partly responsible. General symptoms of poisoning: abdominal pain, weakness and drowsiness. Blood clotting is reduced. Russian Knapweed, Yellow-Star Thistle These plants cause 'chewing disease' in horses. Prolonged consumption of the plants is required to produce the symptoms. Russian knapweed is more toxic than yellow-star thistle. There are no known treatments for horses once the symptoms appear. Chewing disease becomes incurable once clinical signs are present.

Nomenclature Botanical name Centaurea repens L. Centaurea solstitialis L. English Common name: Russian Knapweed, Yellow-Star Thistle Botanical family name: Compositae English family name: Composite Toxic parts: Leaves, stems, all parts Toxic chemicals: toxic agent unknown - Eating 1.8-2.5 kg/100 kg of body weight per day of Russian knapweed causes poisoning after eating 59-71% of body weight of the plant 10

material in about 30 days. - Eating 2.3-2.6 kg/100 kg of body weight per day of yellow-star thistle causes poisoning after eating 86-200% of body weight of the plant material in about 54 days. General symptoms of poisoning: constant chewing activity without food intake, lack of coordination, unsteady gait, restlessness, drowsiness, reduced water intake, leading to death. St. John's Wort (Hypericum perforatum) St. John's Wort is a naturalized herb that contains hypericin, which is a primary photosensitizing chemical. Eating has caused skin problems in horses and other animals. The skin problems occur on white or light-colored skin, dark skin is not affected. Severe symptoms such as convulsions, staggering, and coma have occurred. The reaction is more severe if fresh plants are eaten, but dried plants can also cause photosensitization, even though 80% of the hypericin is lost. Nomenclature Botanical name Hypericum perforatum English Common name: St. John's Wort Botanical family name: Guttiferae English family name: St. John's Wort Toxic parts: flowers and leaves Toxic chemicals: Hypericin, a fluorescent pigment, is a derivative of naphthodianthrone. The pigment is contained in small black dots that are just visible to the naked eye on leaves and petals. The chemical is a primary photosensitizer because the photodynamic action occurs in the skin. General symptoms of poisoning: loss of appetite, staggering gait, peeling of the skin and in severe cases, coma Sensitive Fern (Onoclea sensibis) Sensitive fern is often abundant in low, wet areas, and has been implicated in the poisoning and death of horses. When horses eat hay containing dried sensitive fern, resulting symptoms were similar.

Nomenclature Botanical name Onoclea sensibilis English Common name: sensitive fern Botanical family name: Polypodiaceae English family name: fern Toxic parts: Leaves Toxic chemicals: Toxic agent unknown General symptoms of poisoning: Eating sensitive fern, either in hay or as forage produces the following symptoms: difficulty in eating, 11

falling down, walking as if blind, rubbing against objects, and may lead to death. Old horses are affected more than younger ones. Horses that are worked and are fed a grain supplement, in addition to hay that includes the fern, appear unaffected. Recovery may occur if the horses are given good hay and grain before serious nervous symptoms develop.

Sorghum or Milo, Sudan Grass, and Johnson Grass (Sorghum spp.) Sorghum, Johnson Grass, etc. can contain a cyanogenic glycoside that can produce HCN during times of stress or if damaged by frost or chewing. Modern sorghums have been developed for their low HCN potential and are normally safe. Sorghum can also accumulate toxic levels of nitrates. Nomenclature Botanical name Sorghum bicolor ( L.), Sorgham halepense, Sorghum sudanense English Common name: Sorghum Botanical family name: Gramineae English family name: grass Toxic parts: leaves and stems Toxic chemicals: dhurrin; nitrate. A cyanogenic glycoside, dhurrin, is found in Sorghum spp. After chewing has damaged the plant, plant enzymes convert the glycoside to other chemicals, including HCN. Cyanide, which is lethal, can be released into the animal's system. Since HCN is volatile, silage made from this plant is generally safe. General symptoms of poisoning: HCN causes damage to the lumbar and sacral segments of the spinal cord in horses after they eat sorghum. Large quantities of sediment occur in the urine. If forced to move, affected horses sway from side to side and dribble urine, a condition known as 'sorghum cystitis ataxia'. Other symptoms include an extremely enlarged bladder and patchy softening of the tissue of the brain (encephalomalacia) with associated nerve (axonal) degeneration. Damage is permanent. When fed sorghums during early pregnancy, mares have aborted. Symptoms are the result of oxygen loss due to cellular damage (cytotoxic hypoxia), leading in severe cases to death from asphyxiation. Other symptoms include increased respiration, irregular pulse, frothing at the mouth, and staggering. Yew (Taxus spp.) English yew (Taxus baccata) is an introduced ornamental shrub. This shrub has caused poisoning and death in horses. Eating leaves, bark, or seeds can cause poisoning in all animals. The fleshy fruit pulp is considered to be nontoxic (or low in toxicity). Taxine, a complex of alkaloids, is found in the plant. Animals should not have access to the shrub or clippings of the branches. Nomenclature Botanical name Taxus baccata, Taxus canadensis English Common name: English Yew, Canadian Yew, Japanese Yew Botanical family name: Taxaceae English family name: yew Toxic parts: leaves, pollen, seeds. All parts of the plant contain 12

significant amounts of the alkaloids, with the exception of the fleshy part of the fruits, which is regarded as nontoxic or low in toxicity. The seeds are toxic. Eating the entire fruits without removing the seeds can cause poisoning. Toxicity is not reduced with drying. Hedge clippings from these plants are as toxic as fresh plants. Toxic chemicals: Taxine (taxin) is a complex mixture of alkaloids that is rapidly absorbed from the digestive tract and interferes with heart action. The lethal dose is estimated at 0.5-2 g/kg for horses. General symptoms of poisoning: Eating yew results in the following symptoms: coldness, a rapid and then weak pulse, excitability, then collapse followed by death. Abdominal pains, confusion, staggering gait and lack of coordination may also be noted.

Shrubs, Flowers and Trees Known To Be Safe African Violet (Saintpaulia)Aglaonema (Botanic name) Ajuga Reptans (Botanic name) Albizzia (Botanic name) Alstoemeria (Botanic name) Aluminum Plant (Pilea cadierei) Amaryllis Belladonna (Botanic name) Anemone (Botanic name) Angel Wing Begonia (Species) Artillery Plant (Pilea Microphylla) Asparagus Fern (A. setaceus or sprengeri) Aster, Giant (Townsendia sericea) Baby's Blanket (Thymus serpyllum) Baby's Breath (Gypsophyla) Baby Tears (Helxine soleirolii) Bachelor Buttons (Centaurea cyanus) Bamboo, common (Phyllostachy aurea) Bird's Nest Fern (Asplenuim nidus) Bishop's Weed (Aegopodium podagaria) Blue Spruce (Picea pungens) Boston Fern (Nephrolepsis exalta) Butterfly Bush (Buddleia davidii) Camellia (Thea japonica) Canna Lily (Canna generalis) Canterbury Bells (Campanula) Carob Tree (Ceratonia siliqua) Cockscomb (Celosia argentea) Coleus (Species) Creeping Charlie (Plectranthus australis) Creeping Charlie (Lysimachia nummularia) Creeping Charlie (Pilea nummulariifolia) Crocus, Spring blooming (Species) Dahlia (Species) Dandelion (Taraxacum officinale) Douglas Fir (Pseudosuga taxifolia) Easter Lily (Lilium longiflorum) Elephant Ear (Bergenia cordifolia) Fir (Abies or pseudotsuga) 13

Forget-me-nots (Myosotis)F Forsythia (Botanic name) Fruitless Mulberry (Morus) Fuchsia (Species) Gardenia (Jasminoides) Gloxinia (Sinningia speciosa) Gourd (Cucurbitaceae) Grape Hyacinth (Muscari species) Hemlock, Tree (Tsuga species) Hen and Chickens (Sepervivum tectorum) Hen and Chicks (Echeveria) Hibiscus (Botanic name) Hollyhock (Althaea rosea) Honey locust (Gleditsia triacanthos) Lilac (Syringa) Locust Pods Tree (Ceratonia siliqua) Manzanita (Arctostaphylos) Maple Tree (Silver, Acers Species) Mock Orange (Philadelphus species) Mock Orange (Pittosporum tobira) Mountain Ash (Sorbus aucuparia) Mulberry Tree (Morus species) Nasturtium (Tropaeolum majus) Petunia (Species) Phlox (Botanic name) Purple Passion Vine (Gynura aurantiaca) Red Bud (Cercis Canadensis) Rose of Sharon (Hibiscus syriacus) Silver King (Aglaonema) Snake Plant (Sansevieria Trifasciata) Snapdragon (Antirrhinum species) Snowball Bush (Viburnum) Sphagnum Moss (Botanic name) Strawflower (Helichrysum bracteatum) Swedish Ivy (Plectranthus australis) Sycamore (Platanus) Torch Lily (Kniphofia) Wandering Jew (Zebrina pendula) Weigelia (Botanic name) Willow (Salix) Xylosma (Botanic name) Yucca (Botanic name) Zebra Plant (Calathea zebrina) Zebra Plant (Cryptanthus zonatus) Zinnia (Botanic name)

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