Be Careful if Feeding Unfermented Drought-stressed Feeds
Dairy Pipeline: August 1999
Charles C. Stallings
Extension Dairy Scientist, Nutrition
Many are experiencing a shortage of feed this summer. As a result some are thinking of chopping corn or other forages and feeding without going through the ensiling process. If plants have been drought stressed, there might be high levels of nitrates present. Ensiling for at least three weeks will typically reduce nitrate levels by 50% or more. Also, nitrates accumulate in the stalk so raising the cutter bar may be an option to leave more of the nitrates in the field. However, this may not be effective if levels are high (above .9% of dry matter as nitrate or .2% as nitrate-nitrogen). 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. Make sure water is not also high in nitrates (greater than 133 parts per million nitrate or 30 parts per million nitrate-nitrogen). 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.