6: Toxicants Affecting Nervous System 1

ammoniated feed toxicity

bovine bonkers

how does bovine bonkers occur?

formation of imidazoles

most common clinical sign of bovine bonkers

hyperexcitability

how are imidazoles formed?

ammonia (rumen), soluble sugars (in feed/hay/molasses)

neurotoxins of buckeye/horse chesnuts

aesculin and fraxin

signs of auesculin/fraxin toxicity

weakness, muscle twitching, colic in horses

portosystemic shunt

decreases BF to liver, shrinking it as well as sends ammonia to bloodstream

how can advanced liver disease cause neurotoxicity?

decreased liver function = increased ammonia in blood

metaldehyde toxicity

slug bait

signs of metaldehyde (slug-bait) toxicity

tachycardia, hyperpnea, increased salivation, ataxia, HYPERESTHESIA, hyperthermia, muscle tremors, seizures

hyperesthesia

sensitiv to touch

opisthotonos

muscle tremors/shaking

another name for metaldehyde toxicity (slug bait)

shake n bake syndrome

MOA of slug bait toxin

UNKNOWN

mycotoxins causing neural issues

penitrem A, roquefortine

MOA of penitrem A/roquefortine (mycotoxins)

UNKNOWN

signs of mycotoxin toxicity

vomiting, lethargy, excessive panting, tremors, incoordination, seizures

early signs of lead poisoning

head pressing, "blind"

later signs of lead poisoning

frenzied behavior, bellowing, staggering, crashing into objects, death

species of animals MOST AFFECTED by lead

dogs and cattle

how long is withdrawal time of lead in ruminants?

can be over a year

sources of lead

paint, grease, weights, batteries, golf balls

signs of lead toxicity in BIRDS

anorexia, ataxia, loss of condition, wing/leg weakness, anemia

what does lead affect in ruminants? DURATION?

CNS, acute

what does lead affect in horses? DURATION?

peripheral neuropathy, chronic

what does lead affect in dogs/cats? DURATION?

neuro/GI, acute (neuro), chronic (GI)

what does lead affect in raptors/water fowl?

chronic wasting, peripheral nerve dysfunction

what does lead affect in Psittacines?

GI, neuro, renal, hematological dysfunction

hematologic abnormalities associated with lead toxicity

anemia, anisocytosis, poikilocytosis, polychromasia, basophilic stippling, increased nRBCs, hypochromia

anisocytosis

irregular cell size

Poikilocytosis

irregular cell shape

hypochromia

irregular color of cells

forms of mercury

elemental, inorganic, organic

elemental mercury is in

thermometers, light bulbs

inorganic mercury is in

batteries, paints

organic mercury

aryl/methyl/ethyl

mercury is converted to what in environment? HOW?

methylmercury, anaerobic conditions in bodies of water

where does methylmercury accumulate?

brain, kidney, fetus

minamata disease

japan dumped mercury into sea, got into fish, people/animals ate it and died

signs of sulfur toxicity in cattle

blindness, staggering, unable to rise, sawhorse stances (ridgidity in all 4 legs)

what is present on histology with sulfur toxicity?

polioencephalmalacia

how are cattle exposed to sulfur?

rumen fermentation creates it, taken up by microbes

sulphur invisible boundary for cattle

0.4% of dry matter feed intake