The clinical signs are vague, particularly early on. Early veterinary involvement is therefore important. If your cattle have had access to nitrate and start showing signs of illness, get them checked as soon as possible.Nitrate poisoning can be identified using a blood test for either nitrate or methaemoglobin (the product formed when nitrite reacts with the red blood cells). In severe cases and at PM the methaemoglobin is visible as high levels in the blood result in the blood becoming chocolate in colour