Toxicants Affecting the Nervous System I (6) Flashcards
What are the clinical signs of NPN feed intoxication?
dyspnea, dilated pupils, ear twitching, rapid eye blinking, convulsions
What is urea/non-protein nitrogen converted into when processed by bacteria?
ammonia
What is ammonia then converted into by combing with what?
combined with ketoacids by the microbes to produce amino acids
What is the difference between ammonia and ammonium?
NH3 = ammonia (UNcharged so easier to absorb)
NH4+ = ammonium
What influences ammonium creation?
acidic or neutral environments
Differentiate between NPN feed toxicity and ammoniated feed toxicity
What is the toxin in buckeye, horse chestnut?
glycoside aesculin and fraxin
What are the effects of buckeye and horse chestnut?
weakness, muscle twitching
may produce colic in horses
What is a common clinical sign of PSS or advanced liver disease?
head pressing
What are the effects of a PSS or advanced liver disease?
bypasses the liver —> can’t filter the ammonia —> goes straight to systemic circulation aka the brain
What cells does ammonia get into in the brain regarding PSS or advanced liver disease?
get in glial cells/astrocytes
ammonia combines with glutamate —> glutamine = ROS
What is the toxicant in slug bait?
metaldehyde
What does slug bait cause?
shake-n-bake syndrome
What are the toxins in strawberry mold?
penitrem A
roquefortine
What are clinical signs of lead toxicity?
head pressing, blind
advanced: frenzied, bellowing, staggering, crash into objects
Which species is lead poisoning most common in?
dogs and cattle
Where is lead in a ruminant?
reticulum - slowly dissolves and releases significant quantities of lead
What does lead have a profound effect on?
sulfhydryl-containing enzymes, thiol content of rbcs, antioxidant defenses, tissues rich in mitochondria
Lead poisoning is most common in [old/young] animals
young
What is the half-life of lead in the blood of cattle ingesting particulate lead? Withdrawal times?
> 9 weeks
> 1 year
What are other sources of lead?
paint, linoleum, grease, lead weights, lead shot, contaminated foliage
urban environments and renovation of old houses
How does lead toxicity affect birds - clinical signs?
anorexia, ataxia, loss of condition, wing and leg weakness, anemia
How do birds get lead toxicity?
fishing lures, shot pellets, eating fish that has a hook in it
What are the species differences of lead toxicity?
T/F: Eggs have no correlation with lead toxicity
FALSE - and free range have more concentrations of lead
What are the hematologic abnormalities of lead intoxication?
anemia
anisocytosis
poikilocytosis
polychromasia
basophilic stippling
metarubricytosis
hypochromia
What are the types of mercury?
elemental
inorganic
organic
What is the toxicant of mercury poisoning in the environment with fish?
Inorganic forms of mercury are converted to methylmercury, bioaccumulation in the brain, kidney, fetus
What are causes of sulfur toxicity?
Dried Distillers Syrup (DDG)
Distillers Syrup
Gypsum limiter
Turnip pasture
High Sulfur Water
How do cattle get sulfur toxicity?
released from ingested feed by fermentation in the rumen and is taken up by rumen microorganisms → convert a substantial portion of it into essential amino acids
too much causes clinical signs
What are clinical signs of sulfur toxicity?
blindness, staggering, unable to rise, sawhorse | polioencephalomalacia
How much sulfur should a cow ingest max?
0.4% of cattle’s dry matter feed intake (should only have about 0.15%)
