By Scout Nelson
Drought conditions are increasing the risk of nitrate poisoning in livestock as farmers use drought-stressed crops and forages to meet feed needs. Small grains and other low-yielding crops can provide useful livestock feed, but some may contain dangerous nitrate levels.
North Dakota State University Extension specialists warn producers about the risk and recommend testing drought-stressed forage before feeding it. Miranda Meehan, NDSU Extension livestock environmental stewardship specialist, says, “Plant stresses such as drought can increase nitrate levels in plants.”
Nitrate levels are affected by soil moisture, plant type, and growing conditions. Oats, barley, and corn account for many nitrate poisoning cases in North Dakota. Wheat, sudangrass, sorghum-sudan hybrids, turnips, and pearl millet can also collect nitrates.
Not every drought-stressed plant has high nitrate levels. Plants need some soil moisture to absorb nitrogen. Nitrate levels can remain high for several days after rain. Plants that are stunted but still green and actively growing may have higher nitrate levels.
Nitrate risk is also greater when crops receive nitrogen fertilizer and experience stress between jointing and heading. Broadleaf weeds such as kochia, pigweed, and Russian thistle can create risks in pastures.
Plant parts close to the ground usually contain the most nitrates. Stems and stalks have higher levels than leaves, while seeds and flowers generally contain little or no nitrate. James Rogers, NDSU Extension forage crops production specialist, recommends raising the cutter bar above 6 inches during haying.
Nitrate poisoning mainly affects cattle and sheep. Signs can appear within 30 minutes to four hours and include difficult breathing, weakness, staggering, tremors, blue or brown mucous membranes, and collapse. Severe cases can cause death. Pregnant animals that survive poisoning may also lose their pregnancies.
Dr. Jake Galbreath, NDSU Extension veterinarian, says, “If nitrate toxicity is suspected, avoid moving or stressing cattle, as their blood oxygen levels may be dangerously low.”
Producers can lower risks by testing forage, mixing high-nitrate feed with safer feed, providing dry roughage before grazing, and avoiding overstocking. Chopping and ensiling small-grain forage can reduce nitrate levels by up to 50%, but silage should ferment for 21 days and be tested before feeding.
Photo Credit: minnesota-corn-growers-association
Categories: North Dakota, Crops, Hay & Forage, Livestock