The droughty conditions we experienced earlier in the summer should have stockmen testing forages for the potential for nitrate and prussic acid levels prior to feeding.  Many of the drought stressed forages that were put up for feed may be high in nitrates due to the lack of moisture.
    Many times people confuse the two problems, nitrate poisoning and prussic acid.  Nitrate poisoning is the inability of the blood to transport much needed oxygen.  Prussic acid (also known as cyanide poisoning) prevents oxygen in the blood from transferring to body cells.  The result of both is the same; asphyxiation of the animal.  Diagnosis and treatment of nitrate toxicity should be performed by a veterinarian.
    Sorghum type forages and Johnson grass are the most common forages associated with nitrate and prussic acid poisoning.  But they can also occur with other grass species.
Both of these problems are a concern when grazing the forages.  High nitrate levels persistent in the crop will not decrease over time when the forage is hayed.  It can also occur with hay from oats, barley, wheat and corn.  Ensiling will reduce nitrate levels.
    The following are a few guidelines producers should follow to reduce nitrate toxicity:
     — Pay close attention to potentially troublesome plants, such as sorghum and sudangrass, which often have high nitrate levels.
    — Avoid excessive application of manure or nitrogen fertilizer.
    — Raise cutter bar 6 to 12 inches to exclude basal stalks.  This also will help minimize harvesting many weed species that have accumulated nitrate from shading.
    — Delay harvesting of stressed forages.  A week of favorable weather is generally required for plants to reduce accumulated nitrate.
    — Never feed green chop that has been heated after cutting or held over night.
    — Harvest plants containing high nitrate levels as silage rather than hay.
    — Have representative samples of suspect forage analyzed before feeding.
    Forages suspected to contain high nitrate levels should be tested by a laboratory before feeding.  Paying for the testing is much cheaper than losing an animal.     
    For more information on Nitrate and Prussic Acid Toxicity or Emergency and Supplemental Forages, check out the publications on the Ford County Extension Web site at