Effect of Nitrogen Fertilization of Festuca arundinacea Schreb. on Nitrate Nitrogen and Protein Content and the Performance of Grazing Steers1

Abstract Rapid acceptance of N fertilizer and a concern for nitrate toxicity suggest a need to relate forage nitrate N content to the performance of cattle grazing fertilized grass pastures. The nitrate N and protein contents of Festuca arundinacea Schreb. pastures fertilized with 0, 84, and 168 kg/ha of N were studied. The average daily gain of grazing steers was measured during the sampling period. The nitrate N and protein contents increased, reached a peak shortly after the N was applied, and declined over the remainder of the sampling period. The maximum nitrate N content observed in tall fescue was approximately 0.18%. Average daily gain was not influenced statistically by increasing increments of N fertilizer up to 168 kg/ha. No other effects were observed.