Grain Testing Supports Safe Livestock Feeding

By Scout Nelson

Drought and high temperatures are forcing many South Dakota grain producers to decide whether to harvest grain crops or use them as livestock forage. When grain yields are too low for harvest, these crops can provide valuable feed. However, drought-stressed plants may contain dangerous nitrate levels that can threaten livestock health if they are not tested before use.

Stan Wise from the South Dakota Soil Health Coalition advises that producers should carefully evaluate drought-stressed grain before feeding it to livestock. Testing forage for nitrate levels is an important step that helps farmers make safe feeding decisions while protecting animal health and reducing unnecessary losses during dry conditions.

Grain plants naturally absorb nitrogen to support growth and produce protein. During drought, plants cannot fully use that nitrogen, causing nitrate to build up, especially in the lower two-thirds of the plant. If livestock consume forage with excessive nitrate levels, the nitrate changes into nitrite inside the animal. This reduces the blood's ability to carry oxygen, creating a serious health risk.

High nitrate levels may lead to illness or death in cattle and sheep. Pregnant animals face an additional risk because nitrate poisoning may also cause abortions. South Dakota State University Extension offers free nitrate testing at several locations, while laboratory testing is also available at a reasonable cost.

Experts recommend paying close attention when nitrate-nitrogen levels reach 1,000 parts per million. At that level, the forage may still be suitable for yearlings or non-pregnant animals, but it should make up no more than half of the diet for pregnant livestock. If nitrate levels exceed 4,000 parts per million, the forage should not be fed.

Waiting longer before harvesting drought-stressed grain can help lower nitrate levels because plants naturally reduce nitrate as they mature.

Producers must also decide whether to graze the crop or harvest it as hay. Haying allows forage to be harvested at a consistent quality, while grazing reduces harvesting costs and leaves valuable nutrients in the field. Bale grazing or feeding hay back on the same land also helps return nutrients to the soil.

Leaving crop residue after harvest protects the soil from erosion. Cutting plants slightly higher also avoids the lower stalk, where nitrate levels are usually highest.

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