Dry weather, which has cut crop production in many areas, also raises the potential for nitrate poisoning of livestock, according to veterinary authorities at Colorado State University. Nitrates can accumulate in plants during hot dry weather. The plants that survive a drought may suddenly accumulate high nitrate levels after a rain. CSU's William Brown noted that a survey in the Colorado area, for example, revealed nitrate levels as high as 3.4%, a toxic level, in stocks of drought-affected corn.
Brown concluded that pastures suspected of being high in nitrates should be tested before grazing and that, even if the analysis is negative, a few animals should be allowed to graze as a test before turning out the remainder of the herd.