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88 Cards in this Set
- Front
- Back
Few toxins have pathognomonic signs and in most cases you will discover ______ first.
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A damaged organ
-Differetials then include: toxins that could cause this damage -infectious cause -other causes such as metabolic, allergic, nutritional |
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How should you organize different toxins?
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Into systems effected
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What are 9 plants containing neurotoxins?
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1) Lupine
2) Larkspur 3) Locoweed 4) Yellow star thistle 5) Morning glory 6) Bracken fern 7) Poison Hemlock 8) Water Hemlock 9) Perennial rye grass |
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Where is lupine located?
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Western U.S.
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What are the characteristics of lupine?
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-Legum
-5 petal flower -Blue flower -Raceme (stalk) -Seed pod -Palmate branch leaf |
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What is the toxin in lupine?
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Quinolizidine alkaloids that have nicotinic effect
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Are all species of lupine toxic?
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No, most are not
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What part of the lupine plant contains the toxin?
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Leaf, steam, seed and seed pod
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Lupine is toxic in dry ______.
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Dry hay
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Lupine is toxic at <____% of body weight, or less if eaten for 3-4 days.
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1%
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True or false. Lupine can be passed in the milk.
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True
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Lupine is more concentrated and palatable in ____ stage.
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Seed stage
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Are sheep or cattle more commonly affected by lupine?
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sheep
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What are the 3 toxic principles of lupine?
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1) Hepatotoxic (mycotoxin)
2) Crooked calf (anagyrine) 3) Lupinine alkaloid (neurologic signs) |
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What are the 3 neurologic signs of lupine?
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1) Seizures
2) Ataxia, head pressing 3) Salivation |
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What is the mode of action of the lupine toxin?
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Stimulates nicotinic acetylcholine receptors
-Neuromuscular -Autonomic: sympathetic & parasympathetic |
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What are the 5 clinical signs of lupine toxicity?
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1) Salivation
2) Ataxia 3) Muscle twitching 4) Seizures 5) Head pressing, excitement, nervous -Also causes crooked calf syndrome and hepatotoxicity due to a mycotoxin |
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What are 4 differential diagnoses for lupine?
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1) Other neurotoxic plants
2) Neurotoxic chemicals -Lead -Organic- phosphate 3) Cerebral abscess 4) Meningitis (listeria) 5) Rabies |
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How do you diagnose lupine toxicity?
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Identify plant being eaten
-No specific clinical pathology changes -No visible lesions on postmortem -Test for alkaloid in blood or urine (not readily available) |
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What is the treatment for lupine toxicity?
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No specific antidote
Prevent, don't graze |
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What are the characteristics of larkspur (delphinium sp.)?
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Perennial, alternate leaves, palamate veins and lobes, divided pointed leaves, flowers on terminal racemes, usually 5 blue petals
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What are the 2 types of larkspur?
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Low and tall
-Tall= at higher elevations E |
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Where is larkspur located?
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On western ranges
Grows in undisturbed soil in pastures |
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What part of a larkspur plant is toxici?
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All parts or toxic
Highest in leaves, young plant |
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What larkspur plants are more concentrated?
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The green growing plant and seed
-May, June |
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Larkspur is palatable to _____.
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Cattle
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What are the 2 types of larkspur?
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Tall larkspur
Low larkspur |
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What is the "window" for tall larkspur toxicity?
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Early flowering---> seed pod
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Do sheep or cattle tend to get tall larkspur when the toxin is highest?
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Cattle-they eat more after a rain storm, sheep avoid it when the toxin is highest
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When is low larkspur most toxic? To what animal?
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Eaten in early spring before flowing - when most toxic and tasty to cattle
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What type of toxin is present in larkspur?
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Polycyclic diterpene alkaloids
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What are the 2 types of larkspur?
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Tall larkspur
Low larkspur |
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What is the "window" for tall larkspur toxicity?
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Early flowering---> seed pod
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Do sheep or cattle tend to get tall larkspur when the toxin is highest?
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Cattle-they eat more after a rain storm, sheep avoid it when the toxin is highest
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When is low larkspur most toxic? To what animal?
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Eaten in early spring before flowing - when most toxic and tasty to cattle
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What type of toxin is present in larkspur?
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Polycyclic diterpene alkaloids
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What is the mechanism of larkspur toxicity?
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Polycyclic diterpene alkaloids are neuromuscular blocking agents
-Competes w/ acetylcholine at receptors -Cholinergic and nicotinic receptors |
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What is the toxic dose of larkspur?
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0.5-1.5% BW may be lethald
-0.7% BW in 1 our=lethal |
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Is the toxin in larkspur most poisonous to sheep, cattle or horses?
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Cattle > sheep or horses
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What are 6 clinical signs of larkspur toxicity?
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1) Nervousness
2) Weak staggering gait, paresis -kneel due to weakness 3) Salivation 4) Twitching, tremors 5) Excitement, convulsions 6) Bloat -due to position or foam? |
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How long does it take for sudden death to occur from larkspur toxicity?
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Die in 3-4 hours
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What are 5 differential diagnoses for larkspur toxicity?
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1) Other neurotoxic plants
2) Neurotoxic chemicals -lead -organic-phosphate 3) Parturient paresis, grass tetany 4) Cerebral abscess 5) Meningitis -Rabies could be |
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Is there a definitive test available for larkspur toxicity?
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No, have to identify plant being eaten or possibly identify it in the rumen
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Is there a specific postmortem lesion indicative of larkspur toxicity?
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No, they will have bloat or congestion (But not specific)
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What are 3 things involved with treatment of larkspur?
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1) Relieve bloat
2) Detoxify? activated charcoal, cathartics 3) Physostigmine -old larkspur remedy |
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What are 3 ways to control larkspur toxicity?
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1) Biological, sheep
2) Herbicides 3) Limit grazing until alkaloid <3 mg/g in leaf -social consumption, induced aversion |
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What type of a plant is locoweed, astragalus sp., oxytropis sp., and crazyweed?
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A perennial legume
-resembles sweet pea |
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What are the characteristics of locoweed, astragalus sp., oxytropis sp., and crazyweed?
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Numerous leaves on 2 sides each stem
-Flowers clustered on stalk, 1/2 in long seed pod 1/2-1'' |
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Where is locoweed, astragalus sp., oxytropis sp., and crazyweed located?
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SW Texas
-Not Willamette Valley |
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What are the signs of locoweed, astragalus sp., oxytropis sp., and crazyweed?
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Animal goes loco, crazy
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What is the scientific name of bracken fern?
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Pteridium aquilinum
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Where are bracken fern located? How are they spread?
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A true fern spread by rhizomes
-In wooded hilly areas |
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What are the characteristics of the leaves of bracken fern?
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Leaves shaped like triangle
Bipinnately lobed leaves Brown spores at edge |
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What bracken fern is more palatable?
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young "fiddleneck"
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What is the toxin in bracken fern that poisons horses?
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Thiaminase in horses
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What is the toxin in bracken fern that affects cattle? What does the toxin do?
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Ptaquiloside- a bone marrow depressant
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True or false. Bracken fern toxicity is cumulative.
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True
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How much bracken fern does it take to kill a horse?
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6 lbs/ day for a month
3-5% of diet for 30 days -Toxic in hay |
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What are 2 compounds that contain thiaminase?
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1) Bracken fern
2) Equisetum |
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Thiaminase destroys what vitamin? What is the net effect?
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Vitamin B1 (thiamin)
Central nervous system |
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What is the function of thiamin in the body?
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needed for energy metabolism
-Pyruvate to acetyl CoA -Oxidation of alpha ketoglutarate in citric acid cycle |
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What are the 6 clinical signs of bracken fern toxicity in horses?
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1) Chronic ataxia
2) Weakness 3) Blind staggers ("fern staggers") 4) Twitching 5) Weight loss 6) Head pressing |
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What are the nine differential diagnoses for bracken fern toxicity?
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1) Other thiaminase containing plants
2) Cervical vertebral malformation 3) EPM 4) Neurological herpes 5) Cerebellar disease 6) Equine degenerate myeloencephalopathy 7) Lower motor neuron disease 8) Polysaccharide storage disease 9) West Nile virus |
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What are 3 ways to diagnose bracken fern?
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1) Consuming fern over period of time
2) Blood thiamine levels -Normal 8-10 mcg/dL -Affected 2-3 mcg/dL 3) blood pyruvic acid levels increased Normal 2-3 mcg/dL |
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What is the treatment for bracken fern toxicity?
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Thiamine 5mg/kg, IV
Repeat twice daily |
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How can humans eat bracken fern?
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Some nutrient value in young shoots
-Boil to reduce toxin -Eaten in Asia -Like asparagus -Could eat if lost in forest -Carcinogenic if eaten over time |
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What are 7 plants that cause convulsion or sudden death?
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1) Conium maculatum
-Poison hemlock 2) Cicuta maculata -Water hemlock 3) Delphinium sp. -Larkspur 4) Asclepias -Milkweed 5) Astragalas sp. -Locoweed 6) Lupinus -Lupine 7) Cyanide producing & nitrate concentrating |
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What is the scientific name of poison hemlock?
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Conium maculatum
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What are the characteristics of poison hemlock stems and leaves?
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Hollow stem
Purple spots Parsnip-like root Parsley-like leaves Tall plant=10' |
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What are the characteristics of the poison hemlock flowers?
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White flower
-Umbel, compound, 5 petal -Like Queen Anne's lace |
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True or false. Poison hemlock is palatable.
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False
*Human poisoning |
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What is the toxic dose of poison hemlock?
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Very toxic, walnut size piece of root will kill a cow
-May need more of mature plant |
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What is the mechanism of action of poison hemlock?
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Nicotinic effects
-stimulation followed by ANS paralysis |
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What kind of toxin is in poison hemlock?
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Alkaloids
-Coniine & g-coniceine |
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What are the 6 clinical signs of poison hemlock?
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1) Nervous
2) Trembling 3) Convulsions -less than water hemlock 4) Salivation 5) Bloating 6) Coma |
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How long does it take for poison hemlock to cause death?
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Rapid course
-Sudden death-takes 3-4 hours |
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What are the 5 primary differential diagnoses of poison hemlock?
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1) Other plants causing seizures
2) Cl hydrocarbons, organic PO4, Pb 3) Encephalitis -But poison hemlock too acute 4) Meningitis -but poison hemlock too acute 5) Cerebral abscess -but poison hemlock too acute ~Also rabies & epilepsy |
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How do you diagnose poison hemlock?
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Detect alkaloid in stomach
Observe ingesting poison hemlock |
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What is the treatment for poison hemlock?
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Unlikely anything practical will change outcome
-Evacuate stomach -Respiratory support |
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What are 2 ways to prevent poison hemlock toxicity?
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Don't eat it
Keep out of silage & hay |
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What is the scientific name for water hemlock?
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Cicuta maculata
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Where is water hemlock located?
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In wet meadows and near streams
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What are the characteristics of the leaves of water hemlock?
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Divided leaf w/ veins leading to notch
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What do the flowers of water hemlock look like?
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White umbrella-like flower
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Describe the root of water hemlock.
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Thick w/ hollow chambers
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What is the toxic dose of water hemlock?
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VERY TOXIC ESPECIALLY ROOT
8 oz may kill a cow or 0.2% of BW |
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What is the toxin in water hemlock?
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Cicutoxin- a resinoid or unsaturated alcohol
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What happens within 15 minutes of ingesting water hemlock?
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Seizures
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