Consequently, when plants are stressed, particular precautions must be taken to avoid possible nitrate poisoning, especially when feeding those forages that accumulate nitrate fairly readily. Cause of Nitrate Poisoning Nitrate is not particularly toxic to animals. In the ruminant animal, nitrate is broken down to nitrite faster than nitrite is converted to ammonia. Consequently, when high levels of nitrate are present in the ruminant diet, nitrite accumulates and is absorbed into the blood stream. Once in the blood stream it combines with hemoglobin, which in turn reduces the oxygen-carrying capacity of the blood.
Toxic level depends on how much and how fast nitrate is consumed.
A brownish discoloration of blood is evidence of nitrate poisoning. Death loss and fetal abortions are common results of nitrate poisoning. Nitrate Levels in Plants Nitrates in the soil are the primary source of nitrogen, an essential nutrient of growing plants. Under normal growth conditions nitrates are converted to plant protein at about the same rate as they are taken up by the plant's root system. However, when certain conditions disrupt this balance, roots take up nitrate faster than the plant can convert it to plant protein.