Nitrate toxicity is a well-known metabolic issue in cattle associated with the amount of nitrate in the feed and water; however, it is a complex issue, especially in regards to grazing green forages. Once consumed by cattle, nitrates enter the rumen where microbes convert nitrate to nitrite in a rapid manner. Other microbes convert nitrite to ammonia, but at a much slower rate than those converting nitrate to nitrite. This rapid accumulation of nitrite in the rumen is then absorbed into the bloodstream, where nitrite binds with hemoglobin to form methemoglobin, thus reducing the oxygen-carrying capacity of the animal. As methemoglobin increases, symptoms of nitrate toxicity become worse. At low levels of methemoglobin dry matter intake and performance can be stunted. At moderate levels of methemoglobin, pregnant animals will abort. At high levels of methemoglobin incoordination and death can occur. Continue reading “Nitrates – what we know and where we need to go”
