Eventually the animal may die if not treated intravenously with a methylene blue solution by a veterinarian. Nitrates accumulate primarily in the stems of plants. The leaves do not have as high of a concentration of nitrates. During periods of dry weather, the nitrate levels of plants will increase after a rain. The moisture allows the nitrate in the soil to be absorbed by the plant.
Some moisture needs to be present for plant uptake of soil nitrates.
Frost and hail can also increase plant nitrate content. Nitrates in these instances are increased by decreasing the leaf area, which limits the photosynthetic activity of converting nitrates into plant proteins. Ensiling corn is a method to reduce nitrate concentration. The total nitrate concentration is not completely eliminated. Nitrates in silage may still be a problem if the concentration was extremely high to begin with.