If plants have been drought stressed, there might be high levels of nitrates present. Also, nitrates accumulate in the stalk so raising the cutter bar may be an option to leave more of the nitrates in the field. Since young and pregnant animals are the most susceptible to nitrate poisoning, be careful when feeding drought-stressed feeds to them especially plants in the sorghum family. Plants in the sorghum family are nitrate accumulators. If using feeds that contain nitrates, introduce slowly over a period of several days.
Cows do gain ability to tolerate some nitrate in the ration.
Use other feeds to dilute nitrates in the ration to safe levels. Signs of nitrate poisoning are labored breathing, staggering, and panting. The Forage Testing Lab at Virginia Tech can analyze feeds for presence of nitrates. Samples should be chopped or cut into small pieces before submission.