If plants show signs of drought stress, be careful about using them as fresh forage because nitrate levels may be high. A better option is to use plants as silage, because the silage fermentation process reduces nitrate levels. In either case, testing is critical for safe feeding. Symptoms of nitrate poisoning in livestock include labored breathing, frothing at the mouth and a brownish color of the nonpigmented skin within a few hours after feeding. Silage should be stored at least three weeks before testing and feeding take place.
Testing is available from private companies.
Contact your county Extension agent for a list of laboratories. Have both a nutritional analysis and nitrate test completed on crops. Results will take longer for nitrate tests. Test results will help you determine safe feeding amounts, as well as the need for grain and protein supplements. They often are reduced to empty hulls or a very light grain.