Nitrate and Prussic Acid Poisoning

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Nitrate and Prussic Acid Poisoning

• Floron C. Faries, Jr. DVM, MS
• Professor and Extension Program Leader
• for Veterinary Medicine
• Texas Cooperative Extension
• Texas AM University

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Nitrate in All Forages

• Under growing conditions of moist soil
• In plant nitrate converted to protein
• In plant nitrate does not accumulate
• In rumen nitrate converted to protein

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• Under no growing conditions of stress
• Weather, physical damage, heavily grazed
• In plant nitrate accumulates
• In rumen high nitrate converted to nitrite
• In blood high nitrite is poison
• Nitrite poisoning
• Blood cannot carry oxygen
• Death by asphyxiation

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• Fresh or dry forage
• Johnson Grass
• Sudan
• Sorghum
• Sudan-Sorghum
• Wheat
• Oats
• Rye
• Ryegrass
• Bermuda
• Fescue

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• Weather
• Growth cease/nitrate accumulates
• Cold
• Hot
• Cloudy
• Shade

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• Physical damage
• Growth cease/nitrate accumulates
• Heavily grazed
• Nitrate in lower stems and roots

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• gt1 nitrate of ration
• (gt100 PPM)
• Energy feeds
• gt Conversion

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Prussic Acid in Stressed Forages

• Under growing conditions of moist soil
• In plant prussic acid does not accumulate

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• Under no growing conditions of stress
• Drought, hot, frost, freeze
• In plant prussic acid develops
• In rumen high prussic acid converted to cyanide
• In blood high cyanide is poison
• Cyanide poisoning
• Blood cannot carry oxygen
• Death by asphyxiation

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• Fresh forage
• Johnson Grass
• Sudan
• Sorghum
• Sudan-Sorghum

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• Weather/Damage
• Frost wilt winter
• Hot dry summer
• 3 days
• New growth
• 10 days
• Hay fill