Poisonous Plants

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Poisonous Plants

• Clif Little
• Associate Professor OSU Extension
• Noble/Guernsey Counties
• 740-489-5300 or 740-732-5681

Technical reference source University of
Pennsylvania's Poisonous Plants Home Page,
http//cal.vet.upenn.edu
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Types of Poisons

• Thiaminases
• Interfere with thiamin (B1) utilization
• Loss of condition, unthriftyness
• Endophytes
• Symbiotic usually beneficial to the plant
• Varied effects

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Types of Poisons, contd

• Alkaloids
• Contain nitrogen
• Affect CNS
• Glycosides
• Non-sugar group combined with glucose
• Often cyanogenic, hydrocyanogenic (HCN)

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Types of Poisons, contd

• Photosensitizing substances
• Cause severe reactions to sunlight
• Organic Acids
• Oxalic and tannic most common
• Weakness, incoordination, and death.

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Types of Poisons, contd

• Nitrate
• i.e. corn-silage, pigweed,etc.
• Mycotoxicoses, -- moldy grain
• Mineral, -- ex. High k or water contamination
• Insect, -- ex, blister beetle

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Fall Grass
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Bracken Fern

• Not extremely common in Ohio.
• Leaves and rhizomes, fresh and dried (hay)
• Thiaminase activity 2-4 weeks continuous grazing
• Lose condition, unthrifty, anorexia, reduced bone
  marrow activity, blood in urine.
• Recover with support.

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Tall Fescue

• Very common pasture and hay grass.
• Endophytic fungus
• Late gestation mares, prolonged gestation,
  abortion, weakened foals.
• Research suggesting decreased efficiency in
  growing farm animals.

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Perennial Ryegrass

• Very common in Pastures and Hay.
• Endophytic fungus.
• Less danger if Kept Vegetative.
• Staggers head tremors, nodding movements,
  incoordination.

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Poison Hemlock

• All parts of plant
• Most toxic when fresh/growing
• Odor usually prevents consumption.
• alkaloids
• Dilated pupils, weakness, staggering, respiratory
  paralysis within hours.

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Water Hemlock

• One of most poisonous plants in Ohio
• All parts of plant, toxic
• Symptoms, colic and convulsions, respiratory
  failure, within 30 minutes
• Death within hour

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Jimsonweed

• Common around Barn.
• All parts, including seeds, tropane alkaloid.
• Strong odor, taste, usually not consumed fresh.
• Can be in Hay, or grain
• Within minutes, weak thready pulse,
  incoordination, convulsions, excessive thurst.
• Can result in death.

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Hemp Dogbane

• Indian Hemp, Snakes Milk
• Leaves and stems, glucoside, alkaloids
• Fresh and dry
• Less than 1 ounce is fatal
• Increased temperature, pulse, discolored
  membranes, anorexia, death

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Common Milkweed

• Warm, dry soils, with sunlight
• All parts, green or dried, steroid glycoside.
• Within few hours of ingestion.
• Incoordination, loss of muscle control, thready
  pulse.
• Rarely death

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Nightshade Family

• Glycoalkaloid, Solanine
• GI irritation, CNS problems
• Acute hemorrhagic gastroenteritis
• Weakness, incoordination, difficult breathing.
• Death
• Eastern Black Nightshade, Bittersweet Nightshade,
  Horse Nettle, Groundcherries.

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Eastern Black Nightshade

• Widespread in Ohio
• Found in open, disturbed habitats

Other relatives
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Groundcherries

• 7 species, smooth most common.
• Leaves and unripe fruit toxic.
• Found in both cultivated, reduced tillage and
  pasture/hay fields.

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Horsenettle

• A.K.A. Bull Nettle, Devils Potato
• Found in pastures/hay.
• Many animals avoid eating leaves but will eat
  berries.
• Most toxic in late summer to fall.

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Johnsongrass

• Plant Stress results in cyanide production (HCN)
• Within minutes excitement, incoordination,
  convulsions, labored breathing, bright red venous
  blood. Death due to respiratory failure.
• Chronic poisoning nerve damage.
• Young shoots when wilted, hay not usually a
  problem.
• Nitrate poisoning also possible GI irritation,
  hypoxia.
• Similar grasses Sorghum/Sudangrass, Reed
  Canarygrass.

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Sweetclover

• legume
• Mold is problem, usually in hay or silage, no
  problem when grazed.
• Several weeks before problems are seen.
• Coumarin is converted to Dicumerol.
• Hemorrhages
• Crosses placenta abortions
• Treatment vit-K

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Oaks

• Red Oak,Tannins
• Young leaves, sprouts, acorns.
• Water in which leaves soak.
• GI and renal dysfunction
• Colic, anorexia, constipation, jaundice
• Death can occur.

Gallotoxins from Tannic gallic acid
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Buckeye

• Several species
• Glycosides, saponin, alkaloids.
• Sprouts, leaves, and seeds.
• Depression, incoordination, twitching, excessive
  salivation, colic.
• Many animals may survive with care.

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Black Locust

• Several toxic compounds, toxic protein Robin
• Sprouts, leaves, bark.
• Soaks into water
• Stand with base-wide, depression, diarrhea,
  anorexia, weakness, paralysis, colic, laminitis.
• Severe cases, death from cardiac failure.

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Fruit trees

• Wild Black Cherry, Peach
• Seeds, twigs, bark, leaves
• Frosting causes cyanide to form.
• Consumption of water shortly before Cherry
  increases reaction.
• Excitement, incoordination, convulsions, death
  from asphyxiation, Red Mucosa.

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Yews

• Ornamental, clippings are not good feed.
• Leaves, bark, seeds ARE ALL POSSIBLE SOURCES OF
  TOXINS.
• Green or dry can cause problems.

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Preventing Poisonings

• Know which are dangerous, and when
• Inspect pastures
• Ensure horses not hungry/thirsty
• Buy hay locally
• Maintain appropriate grazing pressure
• Provide supplemental feed as necessary

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Conclusion

• No known treatment for many plant poisonings
• Supportive treatment may help in early stages,
  but problem often not realized until its too
  late.
• Prevention is best form of control

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Ornamental Plants

• Many ornamentals are toxic
• Livestock will readily eat.
• Lupins, foxglove, holly, daffodils, hyacinths,
  azalea, rhododendron.

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Elderberry

• Shoots, leaves, bark
• HCN poisoning
• Bright red mucosa, anxiety, staggering, breathing
  difficulties.

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Red Maple

• Consumption of wilted leaves.
• Dried leaves toxic up to 30 days
• Symptoms within 3-4 days
• Hemolytic anemia, methemoglobinurea, destruction
  of red blood cells.
• Rapid breathing, heart rate, cyanosis, brown
  urine, death.

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Black Walnut

• Jugulone in bark, wood, nuts, roots.
• Primary problem with shavings in bedding.
• Laminitis
• Depression, lethargy, increased temp., pulse,
  respiration, colic.
• Signs clear up if removed.

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Mustards

• Very common
• Seeds and vegetative parts contain toxin,
  glucosinolate
• Mustard oils also irritant.
• Anorexia, severe gastro-enteritis, salivation,
  diarrhea, photosensitization, goiters.

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Amaranth

• Pigweed, Lambsquarter
• Nitrate
• Breathing difficulty, chocolate blood, old are
  stricken first, abortions may occur.

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Common Cocklebur

• Very Common
• Glucoside
• Seeds roots most toxic, seldom consumed.
• Young leaves, root are toxic.
• Rapid pulse,Colic, anorexia, depression.
• Survivors usually have chronic liver disease.

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buttercup
Severe gastrointestinal irritation
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Common Pokeweed

• Common around barns and fence rows, contains
  saponins.
• Horses WILL NOT AVOID
• Roots and leaves
• Excessive salivation, colic, bloody diarrhea,
  birth defects
• Severe toxicity, respiratory failure.

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Field Horsetail

• Common horsetail found along streams.
• Difficult eradicate.
• Green more toxic, but more problems in hay.
• Thiaminase activity similar to Bracken Fern,
  except maintain appetite
• Also excitability, staggering, emaciation.