By Scout Nelson
Dry weather conditions continue creating concerns for livestock producers as forage supplies become limited in many areas. Drought-stressed forage can still provide valuable feed for cattle herds, but producers must carefully manage nitrate levels before grazing, harvesting, or feeding these crops.
Kim Ricardo, SDSU Extension Forage Field Specialist, and Parker Witt explained that many common forage crops and weeds naturally contain nitrates. Crops such as millet, oats, wheat, corn, sorghum, sorghum sudangrass, bromegrass, and orchardgrass may develop higher nitrate levels during drought conditions. Weeds including kochia, pigweed, and lambsquarter can also accumulate dangerous nitrate amounts. Plants normally use nitrates to produce proteins, but drought stress slows this process and causes nitrate buildup inside plant stems.
Fields receiving heavy nitrogen fertilizer or manure applications before dry weather face the highest nitrate risks. Experts explain that the lower part of the plant stem often contains the greatest nitrate concentration. When cattle consume excessive nitrate levels, the nitrate changes into nitrite inside the rumen and reduces the blood’s ability to carry oxygen.
Livestock affected by nitrate toxicity may show signs such as rapid breathing, weakness, muscle tremors, staggering, abortions, or sudden death. Pregnant cattle face added risks because nitrate toxicity may reduce oxygen flow to the fetus, especially during the second and third trimester.
Forage testing remains one of the most important tools for reducing nitrate risks. Quick nitrate strip tests can help identify possible concerns, while laboratory testing provides more accurate results. Producers may safely use forage with elevated nitrate levels by limiting intake, mixing it with low-nitrate feed, or gradually adapting cattle to the ration.
Careful grazing management also helps lower risks. Producers are encouraged to avoid overgrazing drought-stressed forage because nitrate levels are often highest near the lower stem. Experts also warn that rainfall after drought conditions may temporarily increase nitrate accumulation as plants rapidly absorb nitrogen from the soil.
SDSU Extension regional centers continue offering nitrate testing services to help producers make safe forage management decisions during dry weather conditions.
Photo Credit: gettyimages-imaginegolf
Categories: South Dakota, Crops, Corn, Wheat, Sorghum, Livestock, Beef Cattle, Dairy Cattle, Weather