Toxic range plants 2 Flashcards
Lupine
-North America, mountains, fields, roadsides
-highest during early growth (Spring)
-very toxic in sheep, but also affects other animals
Lupine target and mechanism
Targets: CNS, fetus
Mechanism: acute agonists of nAChR and mAChr
Clinical signs of lupine toxicity
*within mins to hours post ingestion
-cholinergic toxidrome
-muscle twitching, dyspnea, weak, coma, death, hypersalivation, depression, agitation
Management of lupine tox
-Antidote: atropine
-supportive care for seizures, remove from pasture
-full recovery possible
Diagnosis of lupine
-animals grazing pastures with lupine present
-plant in rumen/stomach contents
-detection of lupine alkaloids in stomach contents, blood, tissues
Death camas
-mountain foothill rangelands, pastures, meadows
-appears in Spring when other forages are sparse
-resembles wild onion
-all parts of plant are toxic
Species differences for death camas toxicity
Sheep and goats > cattle >other species
Death camas target and mechanism
Target: CNS, heart
Mechanism: altered membrane potential of electrically excitable cells= prolonged opening
Clinical signs of death camas tox
-animals found dead within hours of ingestion
-hypersalivation, vomiting, retching, colic, bradycardia, tremors, ataxia, staggering, weakness
-bradycardia, hypotension
*PM= severe pulmonary congestion and edema, thoracic SC hemorrhage
Management of death camas tox
-no antidote
-supportive care
-low stress handling
*poor prognosis but if an animal survives more than 24hrs=survival possible
Diagnosis of death camas
-found dead on pasture with death camas present
-ID of plant in rumen/stomach contents
DDx of death camas tox
-cyanobacterial toxins
-lead
-nitrite
-cyanide
-other cardiotoxic plants
-acute selenium poisoning
-OP/carbamate insecticides
-poison hemlock
-water hemlock
Locoweed
-all growth stages and parts of plant are toxic and dangerous year round
-found on/in mtns, foothills, plains, semi arid desert, marginal soils
-not controlled by herbicides
Toxin of locoweed
Swainsonine
Target and mechanism of locoweed
Target: CNS, kidneys, liver, heart, fetus
Mechanism: Competitive with mannose resulting in accumulation of oligosaccharides in lysosomes= vacuolation of cells
Species sensitization of locoweed
Horses> cattle and sheep
Locoism
Chronic onset (weeks)
-chronic wasting disease with CNS depression
(poor haircoat, neuro signs, depression, weight loss)
Main histological sign of locoism
Cytoplasmic vacuolation of neurons and viscera
Management of locoweed
-no antidote
-remove from pasture
-supportive care
**neuro recovery is unlikely; vacuolation reversible
**fair prognosis if early; severe neuro=poor
Diagnosis of locoweed tox
-animals in pasture with locoweed
-detection of swainsonine in serum, urine, milk
-characteristic histo lesions
DDx for locoweed
-yellow star thistle
-horsetail/bracken fern in horses
-hepatic encephalopathy
Horsetail
-throughout N. America
-only affects horses, but they will only eat if feed unavailable
Toxin of horsetail
Thiaminase
Target of horsetail
CNS
Clinical signs of horsetail
-chronic onset 2-3wks of ingestion
-CNS and wasting disease
(scruffy appearance, general ataxia, convulsions, staggering gait, death)
Management of horsetail tox
-Antidote= thiamine (but before severe neurological point)
-supportive care
Diagnosis of horsetail tox
-presence of horsetail near pastures/in bales
-positive response to thiamine therapy
DDx of horsetail toxicity
-yellow star thistle
-locoweed
-bracken fern
Bracken fern
-entire plant is toxic
Toxin of bracken fern in cattle
ptalquiloside
-causes carcinogenicity and bone marrow suppression
Toxin of bracken fern in horses
Thiaminase resulting in CNS signs
Bracken fern tox clinical signs for horses
Bracken staggers
-chronic congestion
-incoordination, odd posture, weakness
-Terminal= opisthotonos, chronic seizures with tachycardia
Management of bracken fern tox
-Antidote= thiamine
-supportive care
Diagnosis of bracken fern
Plant ID
-no send out test
Prognosis of bracken fern tox
Good if ID’d early and thiamine therapy started
