Ammonium Hydroxide Treatment of Wheat Straw

Chopped wheat straw, containing increasing amounts of added water was treated with a constant level of ammonia (3.3 percent of straw dry matter) as ammonium hydroxide, and stored for I to 60 days before determing in vitro dry matter digestibility (IVD MD), nitrogen content and fiber-bound nitrogen (ADF-N) versus free ammonia nitrogen (NH3N) of the treated sample. The overall improvement (e.g., mean of all day X moisture treatment combinations) in IVDMD of treated versus untreated straw was about 33 percent, whereas nitrogen content of treated straw was increased from 4.6 percent crude protein to 11.0 percent crude protein. Fiber-bound nitrogen and NH3N accounted for 12.6 and 43.4 percent of the retained nitrogen, respectively, when averaged across all day X moisture treatment combinations. The ammonium hydroxide treatment increased straw digestibility by (I) directly decreasing the total cell wall fiber (NDF) and hemicellulose fractions (perhaps by solubilization effects), and (2) increasing the digestibility of the NDF, hemicellulose and cellulose fiber fractions.