Nitrate Poisoning: What Livestock Producers Need to Know

Submitted by: Gilbert Barrett 

 As we move through the growing season, livestock producers across
Northeast Georgia and the Southeast should remain aware of the risk of nitrate
poisoning in both grazed and harvested forages. While nitrate accumulation is often
associated with drought-stressed crops, several common forage species can develop
dangerous nitrate levels under a variety of growing conditions.

Forages Most Commonly Associated with Nitrate Accumulation
Several warm-season annual grasses are particularly prone to accumulating nitrates,
including:
Sorghum
Sudangrass
Sorghum-Sudangrass Hybrids
Johnsongrass
Pearl Millet
Crabgrass
However, producers should not overlook perennial forages. Under certain conditions,
nitrate levels can also become elevated in:
Tall Fescue
Bermudagrass
Annual Ryegrass
Small Grains such as Oats, Wheat, and Rye

When Are Nitrates Most Dangerous?
Plants naturally absorb nitrates from the soil and convert them into plant proteins.
Problems occur when environmental conditions cause nitrate uptake to exceed the
plant's ability to utilize them.

The highest-risk situations include:

Drought Stress

During periods of drought, plant growth slows while roots may continue absorbing
nitrates from the soil. When moisture returns, nitrate concentrations can become
elevated in the forage.

Extended Cloudy Weather
Several days of cloudy conditions reduce photosynthesis, limiting the plant's ability to
convert nitrates into proteins.

Heavy Nitrogen Fertilization
Fields receiving large amounts of poultry litter, commercial fertilizer, or manure often
have increased nitrate risk, especially when environmental stress follows application.

Cool Temperatures
Cold weather can slow plant metabolism and contribute to nitrate accumulation.

Following a Drought-Breaking Rain
One of the most dangerous situations occurs after a drought-ending rain. Plants rapidly
begin growing and can accumulate nitrates. Producers should use caution before
immediately grazing or harvesting stressed forage.

Immature Forage Growth
Young, rapidly growing plants frequently contain higher nitrate concentrations than
mature stands.

How Nitrate Poisoning Affects Livestock
When cattle consume excessive nitrate levels, nitrates are converted in the rumen to
nitrites. Nitrites interfere with the blood's ability to carry oxygen, effectively causing
animals to suffocate internally.

Common symptoms include:
 Rapid breathing
 Muscle tremors
 Staggering
 Excessive salivation
 Bluish discolor ration of the eyes and mouth
 Weakness
 Sudden death
 In severe cases, death can occur within hours of consumption.

Hay Is Not Always Safe

Many producers mistakenly believe baling forage eliminates the risk. While some nitrate
reduction may occur during the curing process, dangerous nitrate levels can remain in
hay.
For this reason, testing is especially important when hay is harvested from drought-
stressed or heavily fertilized fields.

Management Practices to Reduce Risk
Livestock producers can help reduce nitrate poisoning risks by:
 Testing suspect forage before grazing or feeding.
 Avoiding grazing immediately after a drought-breaking rain.
 Waiting several days following environmental stress before harvesting or grazing.
 Raising cutter bars when harvesting high-risk forages, since nitrate
concentrations are typically highest in the lower stem.
 Gradually introducing livestock to suspect forage.
 Providing supplemental hay before turnout to reduce intake of potentially high-
nitrate forage.
 Testing Is Your Best Insurance

Nitrate levels cannot be accurately determined by appearance alone. A forage that
looks excellent may contain dangerous nitrate concentrations, while stressed-looking
forage may be perfectly safe.The only reliable way to know is through laboratory testing.

Farmers Exchange Can Help
At White County Farmers Exchange, we can assist producers with forage and hay
nitrate testing. Whether you're evaluating standing forage, baled hay, sorghum-sudan
fields, Johnsongrass, crabgrass, millet, fescue, Bermuda, or other forage crops, our
team can help you collect samples and obtain accurate laboratory results.
Before grazing or feeding questionable forage, let us help you determine the risk. A
simple test can protect your livestock investment and provide peace of mind.

For more information on forage testing, contact the agronomy team at White County
Farmers Exchange. We are committed to helping producers make informed decisions
and maximize forage quality while protecting herd health.