Toxic Plants in Large Animals Flashcards
Which species does yellow star thistle affect?
Horses
Where is yellow star thistle located?
Western/upper midwest
What is the clinical onset of signs associated with yellow star thistle like?
Abrupt
What are the clinical signs associated with yellow star thistle?
- Involuntary chewing movements
- Food falling from the mouth
- Twitching of the tongue and lips
How does yellow star thistle cause death?
Starvation
What are the lesions associated with yellow star thistle?
- Necrosis of globus pallidus
- Necrosis of substantia nigra
“Nigropallidal encephalomalacia”
What is the treatment for yellow star thistle toxicity?
None - recommend euthanasia
Yellow start thistle requires ____-____% BW for toxicosis.
59 - 200% (requires an extended period of consumption)
What component of Locoweeds causes the clinical signs?
Swainsonine
What is the MOA of swainsonine in Locoweeds?
Is it an enzyme inhibitor
Inhibits alpha-D mannosidase and golgi mannosidase II –> oligosaccharides buildup in lysosomes of brain cells –> generalized lysosomal storage disease ensues
True or False: Swainsonine crosses the placenta, but is absorbed rather slowly.
True/False: Swainsonine does cross the placenta, but it is RAPIDLY absorbed.
True or False: Swainsonine is secreted in the milk.
TRUE
True or False: Swainsonine is excreted in the urine unchanged.
TRUE
Describe the onset of signs associated with locoweed consumption.
Signs usually only observed after several weeks of consumption
What type of signs would you see in a horse due to locoweed consumption?
Neurological signs: ataxia, circling, proprioceptive deficits
What type of signs would you see in a cow or sheep due to locoweed consumption?
Reproductive problems: abortion, testicular atrophy, decreased spermatogenesis
Sheep: blindness, star gazing
What type of lesions would you see with locoism?
Vacuolation of neurons, renal tubular epithelia, and macrophages
True or False: The vacuolation associated with locoism is IRREVERSIBLE.
FALSE: The vacuolation is reversible.
Which species are most severely affected by Jimson weed?
- Pigs
2. Horses
What is the toxic principle of Jimson weed?
Tropane alkaloid
What is the MOA of Jimson weed?
Anticholinergic effects at muscarinic receptors in the CNS
What would the clinical signs of Jimson weed consumption be?
Similar to an atropine overdose:
- Decreased salivation
- GI stasis
- Mydriasis
- Tachycardia
- Muscle twitching
How would you treat a Jimson weed toxicity?
- GI detoxification
2. Physostigmine
What is the toxic principle of Lupine (Bluebonnet)?
Quinolizidine alkaloid
Lupanine is a quinolizidine alkaloid. To which receptors does it bind?
- Nicotinic
2. Muscarinic
Anagyrine is a quinolizidine alkaloid. How does this affect cattle?
Teratogenic alkaloid in cattle (NOT in sheep however)
What are the clinical signs associated with Lupinus spp. in sheep?
- Labored breathing
- Salivation
- Head pressing
- Ataxia
What causes death with Lupinus spp. (Lupine, Bluebonnet)?
Respiratory paralysis
What are the clinical signs associated with Lupine/Bluebonnet consumption in the cow?
- Salivation
2. Teeth grinding
Consumption at what point during gestation causes problems in calves?
Days 38 - 70 of gestation
What causes “crooked calf disease”?
Lupinus spp.
What is the toxic principle of Poison hemlock?
Piperidine alkaloids
___% BW of poison hemlock is lethal in cattle.
0.5%
___% BW of poison hemlock is lethal in sheep.
1%
When do clinical signs occur after consumption of poison hemlock?
Within 1 hour
When does death occur following consumption of poison hemlock?
Within 2-3 hours
What is the cause of death associated with poison hemlock consumption?
Respiratory failure (respiratory paralysis)
What type of lesions would you see in adult animals following poison hemlock toxicity?
NONE
How would you diagnose a poison hemlock toxicity?
Detect piperidine alkaloids in (1) stomach content, (2) serum, or (3) urine.
Where is Larkspur located within the U.S.?
Western U.S.
What is the toxic principle of Larkspur?
Diterpene alkaloids
What is the MOA of Larkspur?
Blocks action of nicotinic acetylcholine receptors
At what point does Larkspur have high toxicity and low palatability?
When young
What are the clinical signs associated with Larkspur?
- Bloat (inability to eructate)
- Sudden death
- Stiffness, weakness, staggering, ataxia, paralysis, tremors
Which species is more susceptible to Larkspur toxicity, cattle or sheep?
Cattle
How would you treat a Larkspur toxicity?
Cholinesterase inhibitor (physostigmine)
What is the toxic principle of water hemlock?
Aliphatic alcohol