Death loss from nitrate is an occasional problem in cattle consuming certain annual forages, particularly sorghum hybrids. Cattle producers should be concerned if rations contain over 5,000 ppm nitrate on a dry matter basis. Avoid poisoning with good management practices. A qualitative check called the diphenylamine test can be used to screen forages for potential harm. High nitrate forages can be used if diluted with other feedstuffs and supplemented with energy.
Nitrate toxicity is sometimes a lethal problem for livestock especially during the fall.
If uptake exceeds the rate of reduction, large amounts of nitrate can accumulate. If the rate of reduction equals the rate of uptake, there is no accumulation. Nitrate accumulation usually results from plant stress, such as drought, and is accentuated by excessive soil nitrogen. Most nitrate accumulates in plant stems rather than leaves, and concentration tends to be highest in immature forage. A characteristic symptom of nitrate toxicity is a chocolate-brown color to the blood.