Animals experiencing acute nitrate poisoning may die within 4 hours. Response time is critical, as acutely affected animals may die within a few hours. It is important to note that methylene blue is not an approved drug for use in food animals. Please consult your veterinarian for more information. If you suspect your forage may be high in nitrate it is a good idea to have it tested.
Many commercial laboratories offer nitrate testing in forage crops.
It is important to note that laboratories vary in their method of reporting nitrate concentrations. There is a great deal of variability in the range of susceptibility between cattle and these ranges are provided only as general guidelines. Cattle Producer's Library CL 620. Nitrate Poisoning in Livestock. University of Nevada.