Nitrate Poisoning Flashcards

1
Q
A
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2
Q

Know me

A
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3
Q

What are some conditions that cause increasing nitrate?

A
  • lack of sunlight and bad weather
    • nitrate reductase inhibition
      • leads to storage
  • herbicides (2, 4D) –> not enough to kill plant
  • diseases
  • soil nutrient imbalance
  • exposure to rain
    • movable
    • in stacks, concentrates in lower bales
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4
Q

Where is nitrate concentrated in plants?

A

lower part *6 in* high in nitrates

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5
Q

Explain processing of nitrate

A
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6
Q

What role does methemoglobinemia play in nitrate poisoning?

A
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7
Q

What are some symptoms of nitrate poisoning?

A
  • Rapid RR & HR
  • Ataxia
  • Frothing at mouth
  • Clinical signs of present @ 30-40% Hb
  • Death @ 80-90% met Hb
  • Chronic poisoning
    • abortion in 10-14 d
    • reduced weight gain/ milk production
  • Before death- brown/blue color membranes
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8
Q

What is a treatment for nitrate poisoning?

A
  • IV Methylene Blue
    • MetHb Fe3 –> Hb Fe2+
      • 1-4% solution
      • 1g/250 #
      • Avoid stressing animals
      • give adrenalin
  • For sub-lethal dose
    • Vit A deficiency–> give Vit A
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9
Q

How do you prevent nitrate poisoning?

A
  • test H2O and feed (cheap if only 1-2 samples
  • Understand lab results
  • Control weeds (native and invasive)
  • Aclimate livestock slowly
  • Feed as silage (silo fillers disease)
  • Feed to low-risk animals (monogastrics, healthy, dry, cows)
  • Raise cutter bar by 6”
  • Keep away from fertilizers
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10
Q

What are some factors affecting toxicosis?

A
  • Ruminant vs. monogastric (cattle most susceptible, sheep less so)
  • High nitrate feed and water (double loading)
  • Animal condition (Health, hunger, pregnancy)
  • Rumen microbes and sudden diet change
  • Diet components (grain vs. grass)
  • Rate of ingestion or acclimation
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11
Q

Nitrate accumulating plants include…?

A
  • Higher proportion of weeds (invasives)
  • frequently exposed to N fertilization
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12
Q

What are some invasive nitrate-accumulating species?

A
  1. Avena fatua- Wild oat grass
  2. Chenopodium album- Lamb’s-quarter
  3. Cirsium arvense- Candian thistle
  4. Concolculus arensis- Field bindweed
  5. Echinochloa crus-galli- Barnyard grass
  6. Kochia scoparia- Kochia
  7. Malva neglecta- common mallow
  8. Salsola iberica- russian thistle
  9. Sorghum halepense- Johnson grass
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13
Q

What are some native/crop nitrate accumulating species?

A
  • Helianthus annuus- common sunflower
  • Ambrosia spp. - ragweed
  • Sorghum sudanense- Sudan grass
  • Medicago sativa- Alfalfa
  • Melilotus officianalis- Sweet clovers
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14
Q

Describe Delphinium spp.

A

Larkspur (toxic alkaloids)

  • Main toxin- Norditerpenoid alkaloids
    • MDL types –> greater concern b/c higher concentration present
    • MSAL typers–> 3 subgroups; most toxic
  • Species grouped by Habitat/Height
    • Low in lowlands
    • Plains- WY and CO (intermediate height)
    • Tall- Alpine/high elevation; responsible for most intoxication
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15
Q

Where are toxins concentrated in larkspur

A

Seeds and New growth

*Be able to draw and label

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16
Q

What are some symptoms of larkspur poisoning?

A

Extreme bloating

trembling

stagger

wide stance–> kneeling–> recumbancy

17
Q

What is the mechanism of larkspur poisoning?

A

Toxin competitively binds to the ach receptors

18
Q

How do you prevent larkspur poisoning?

A
  • Careful planning of grazing
    • planning phenology
    • species (sheep 1st b/c handle 5x higher dose)
    • avoid toxic window
  • Graze sheep 1st
  • Herbicide
    • not best option (widespred plant and native)
    • Picloram (Tordon)
    • Metsulfuron (Escort)
    • Glyphosate (Roundup)
19
Q

Describe Aconitum columbianum

A

Western monkshood

  1. Toxicity:
    1. Diterpenoid alkaloids
    2. all parts and all species
    3. 0.075% of BW can kill a horse
  2. Mechanism
    1. neuromuscular issues
      1. cardiac conduction
  3. Symptoms
    1. Similar to larkspur, easily confused
  4. Treatment
    1. NO ANTIDOTE
    2. can treat symptoms (bloating)
    3. limit further absorption w/activated charcoal
20
Q

Describe conium maculatum

A

Poison hemlock

  1. Naturalized species
  2. Toxicity
    1. piperidine alkaloids (strong odor)
      1. Conine
    2. Leaves and stems most toxic
  3. Symptoms
    1. death in 2-3 hrs
    2. cattle: >0.5% BW of green plant
    3. Respiratory paralysis, muscle tremors, skeletal deformities (fetus), coma
  4. Treatment
    1. NONE
21
Q

Describe Cicuta douglasii

A
  1. Western water hemlock
  2. Similar habitat to poison hemlock
  3. Toxicity:
    1. Cicutoxin (potent neurotoxin)
    2. roots are most toxic
    3. LD50= 50-100 mg green plant/kg BW
  4. Symptoms
    1. tremors, convulsions, grand mal seizures, death in 2-3 hrs
  5. Treatment
    1. NONE
    2. Sodium pentobarbital to combat neurological symptoms if caught early
  6. Prevention
    1. Dig up and Burn
22
Q

What are the 2 groups of cardiac glycosides?

A

Cardenolides

Bufadienolides

23
Q

Describe cardiac glycosides?

A
  1. 11 unrelated plant families
  2. 34 genera with cardiac effects
  3. seeds and new growth high concentration but whole plant poisonous
  4. Therapeutically used in CHF
    1. Digoxin
    2. Digitoxin
    3. Digitonin
24
Q

Describe asclepias spp.

A
  • Milkweeds
  • lots of toxins- latex sap
    • common in hayfields but still toxic when dried
25
Q

Describe apocynum spp.

A
  • Dogbane or Indian Hemp
  • Have milky sap, but NOT milkweed
26
Q

Describe nerium oleander

A

Oleander

  • cardenolides
    • oleandrin
  • From meditteranean horticulture species
27
Q

What are cardiac glycoside’s mechanism of action?

A

Slows/stops repolarization

increases cardiac output and slows HR (good at low level for CHF)

28
Q

What is the toxicity of dogbane, oleander, and milkweed?

A
  • Dogbane- not typically an issue
  • Oleander- 0.005% green tissue BW lethal in horses/cattle
  • Milkweed- latex
29
Q

What are the clinical signs of cardiac glycosides?

A
  • GI Symptoms
    • hemorrhagic enteritis
    • abdominal pain, diarrhea
  • Heart symptoms
    • heart block
    • arrythmias
    • hypotensions
    • kyperkalemia (high blood K+)
      • oleander
  • Postmortem
    • myocarditis
    • lesions
    • CG- blood serum, urine, tissues, stomach contents
30
Q

How do you treat cardiac glycosides?

A
  • Gastric lavage
  • activated charcoal
  • rumenotomy
  • IV fluids (No Ca2+ –> helps toxin)
  • Antiarrythmic drugs
    • KCl- not reccomended
    • Atropine sulfate
31
Q

Describe Taxus brevifolia

A

Pacific/Western Yew

  • Taxine A & B (Isolated for Taxol- breast cancer drug)
  • 10+ alkaloids present
  • winter leaves
  • Na+/K+ ATPase inhibitor
  • Treatment
    • no antidote
    • supportive therapy (symptomatic)
    • Treat w/herbicide and avoid in early spring (less forage available so likely to be eaten and most toxic)
    • Don’t plant; remove from enclosures
32
Q

Describe zigadenus spp.

A

Death camas

  • Steroidal alkaloids
  • zygacine/zygadenine
  • sheep
  • LD50: 2-2.5# green plant / 100 # BW
  • early spring
  • Mechanism
    • lowers BP
      • dilates arterioles
      • constricts veins
      • slows HR
  • Symptoms
    • start at 0.5# staggering gate
  • Treatment
    • No antidote
    • supportive therapy (symptomatic)