Nitrate Flashcards
Why does nitrate accumulate in the plant?
Nitrate is supposed to convert nitrite then to ammonia then to plant protein.
If nitrate-to-nitrite is reduced, nitrate will accumulate in the plant
What type of soil will increase plant nitrate?
Moisture, acidic, low molybdenum, sulfer or phosphorus, low temperature, drought
T/F decreased light reduces activity of nitrate reductase (nitrate accumulation)
True
T/F use of phenoxyacetic acid herbicides increases nitrate accumulation in the plant
True
T/F Old plants have higher nitrate than young plants
False, young plants have more
What are some causes for increased nitrates/nitrites in the animal?
Rapid ingestion of forages in high nitrate fertilizer or overdose of sodium nitrate IV (vasodilator)
T/F ruminants are most susceptible to nitrate poisoning
True
T/F horses are resistant and pigs are sensitive
False, other way around
Which is more toxic, nitrate or nitrite?
Nitrite is 10 times more toxic that nitrate
Are younger animals more susceptible or older animals?
Young
What diseases could increase toxicity of nitrate?
Anemia and Methymoglobinemia
What has a longer half life, nitrate or nitrite?
Nitrate = 4-48hrs Nitrite = 1hr
What is the mechanism of action for ACUTE nitrite toxicosis
Nitrite interacts with 2 hemoglobins.
Ferrous iron is converted to ferric.
Hemoglobin is converted to methemoglobin.
What % methemoglobinemia do you need for anoxemic death?
80%
Does nitrite cause fetal death?
Yes, methemoglobinemia crosses placenta
What is the mechanism of action in CHRONIC nitrate toxicosis?
Nitrate decreases progesterone leading to abortion
Clinical signs of nitrate toxicosis?
Rapid death within 30min to 4 hours.
Dyspnea, ataxia, cyanosis
What is the only postmortem sample stable enough to detect nitrate toxicosis?
Ocular fluid
What two tests can you do to dx at post mortem?
Concentration of methemoglobin
Or
Diphenylamine test - dark blue color indicates positive test for nitrate (qualitative)
Differentials for nitrate toxicosis?
Hemolytic agents, carbon monoxide, cardiac toxicants
What is the treatment for nitrate toxicosis?
Methylene blue IV slowly
Not in cats
What is the prognosis?
Bad,mutually die before treatment bc death is so rapid
What plants are involved in nitrate poisoning?
Pigweed Johnson grass Alfalfa Corn/maize Lambs quarters Sweet clover
What part of the plant is most and least toxic?
Most = stalk Least = seed/flower
