Cattle producers who experienced a dry summer in North Dakota are finding above normal nitrate levels in oat hay. High levels of nitrate in feed can be toxic to cattle. NDSU Extension livestock systems specialist John Dhuyvetter recommends producers test oat hay before feeding it to livestock. Samples with 1,500 to 3,500 parts per million can be diluted with low-nitrate feeds. Levels below 1,000 ppm are considered safe for pregnant cows and heifers, and levels below 1,500 ppm are safe for all other cattle.