Molybdenum toxicosis Flashcards Preview

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Flashcards in Molybdenum toxicosis Deck (16)
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1

Sources?

  • Excess molybdenum
    • Soil rich in molybdenum, or contaminated w/ molybdenum (FL, CA, OR, NV)
    • Plants can accumulate molybdenum from soil
    • Industrial contamination (brick plants, steel mills)
    • Molybdenum-containing fertilizers
  • Cu deficiency 

2

What states have soil rich in molybdenum?

Florida, California, Oregon, Nevada

3

T/F: Molybdenum is an essential trace element

TRUE

4

What is molybdenum a component of?

xanthine oxidase, which converts the purine xanthine to uric acid

5

What does elevated molybdenum interfere with?

Copper absorption

6

What does excess molybdenum cause?

Copper deficiency

7

Which species is most susceptible to molybdenum toxicosis? Which is resistant?

Cattle are the most susceptible (though has been seen in sheep as well)

Horses and pigs are resistant

8

What increases molybdenum toxicity? What decreases it?

High levels of dietary sulfate increases toxicity

Dietary copper decreases toxicity

9

What is the max tolerable dietary level of molybdenum?

5-10 ppm

10

Where is molybdenum absorbed from? Where is it excreted in toxic levels?

Absorbed from GI tract, excreted in milk in toxic levels

11

Mechanism of action of molybdenum toxicosis (plus copper roles)?

  • Copper deficiency
  • Copper is involved in hematopoeisis, CT metabolism, myelin formation in newborns, pigmentation, and bone formation
  • Copper is a component of essential enzymes such as cytochrome oxidase and aromatic amino acid-metabolizing enzymes (tyrosinase, dopamine hydroxylase, MAO)
  • Copper-containing proteins (cupreins) in most aerobic cells have superoxide dismutase activity

12

Clinical signs?

  • Severe diarrhea (greenish, with fluids and gas bubbles) after 8-10 days following exposure
  • Rough hair coat and depigmentation (achromotrichia) of hair especially around the eyes ('spectacled' appearance)
  • Loss of weight, anemia, osteoporosis and exostosis, lameness, and pica
  • Decreased libido in bulls and infertility in cows

13

What is elevated on the lab diagnosis?

Elevated molybdenum in the blood (> 0.1ppm) and in the liver (> 5ppm)

14

What is decreased on the lab diagnosis?

  • Decreased Cu in the blood (< 0.6ppm) and liver (< 10ppm)
  • Decreased cytochrome oxidase activity (Cu deficiency)

15

DDx?

  • Selenium deficiency (?)
  • Frostbite
  • Fluoride poisoning  
  • Ergot

16

Treatment?

  • Copper glycinate SC/IM (60mg for calves, 120mg for cattle)
  • Cu sulfate added to the diet (1g daily per adult cow)