NDSU Experts Urge Care Before Grazing or Harvesting Forage
Dry conditions can increase nitrate levels in forage and create health risks for livestock. North Dakota State University (NDSU) Extension specialists are urging farmers and ranchers to take precautions when managing drought stressed forage after rainfall.
Healthy plants normally absorb nitrate from the soil and convert it into proteins and amino acids as they grow. During drought, plant growth slows, but nitrate uptake can continue. As a result, nitrates may build up inside the plants.
Rainfall does not immediately remove this risk. When drought stressed plants receive moisture, nitrate levels can actually rise for a short period as the plants begin growing again and process stored nitrates.
“Following a rain event, nitrate levels may actually spike two to three days after the rain,” says James Rogers, NDSU Extension forage crops production specialist.
Rogers recommends giving plants seven to 12 days of good growing conditions before allowing livestock to graze. Producers should also provide a similar recovery period before harvesting forage for hay.
Even after this waiting period, forage should not be considered safe without proper testing. Nitrate levels can remain high, especially when drought conditions have been severe.
“Even after allowing a seven- to 12-day recovery period following a rain event, do not assume that nitrate concentrations in forage have dropped to a safe level,” says Karl Hoppe, NDSU Extension livestock systems specialist.
Producers should also consider the quality of livestock drinking water. Water containing nitrates can add to the overall nitrate exposure. When feeding a mixture of hays, farmers should know the nitrate levels of every hay source used in the ration.
Ashley Ueckert, NDSU Extension agriculture and natural resources agent, encourages producers to test forage following rainfall.
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