EFFECTIVENESS OF ANHYDROUS AMMONIA AS A PRESERVATIVE FOR HIGH-MOISTURE ALFALFA HAY IN LARGE ROUND BALES

Abstract

Two experiments were conducted in sequence to determine the effectiveness of anhydrous ammonia (AA) as a preservative of alfalfa hay stored as large round bales (LRB). In the the first experiment application of 3% AA (wt/wt) to alfalfa hay baled at about 23% moisture-content (MC) increased the temperature markedly above the control treatment and resulted in a significantly (P < 0.05) higher acid-detergent-insoluble nitrogen and acid-detergent lignin. In the second experiment application of about 1% AA slowly (over 48 h) to LRB of alfalfa hay packaged at about 30% and > 35% MC, significantly (P < 0.05) reduced the cumulative degree-days above all reference points from 35 to 65 °C. Ammoniation completely eliminated dry matter losses in storage which were highest (8.3%) for 33% MC control hay. High moisture control hay (33% MC) suffered severe heat damage with 33% of total N being in the acid-detergent-insoluble fraction as compared to less than 10% for medium-moisture (26% MC) control and even lower values for ammoniated hay. Digestibility of crude protein and energy was significantly (P < 0.05) improved by ammoniation of medium-moisture (about 30% in-to-storage) alfalfa hay. When the ammonia-treated hay was uncovered in spring, coarsely ground and stored in a hay wagon the high-moisture-ammoniated hay (> 35% MC) became moldy within 4 wk, even when the ambient temperature was about 6 °C, whereas medium-moisture-ammoniated hay (about 30% MC) showed some deterioration after 7 wk as the ambient temperature increased to about 12 °C. Key words: Ammonia, alfalfa hay, digestibility, heat damage, high-moisture hay, large bales