The experiment was conducted to evaluate the changes on the chemical composition and the in vitro dry matter digestibility (IVDMD) of the Brachiaria decumbens Stapf, jaraguá (Hyparrhenia rufa Ness Stapf) hays, untreated, treated with urea (5.4% DM), urea (UL-5.4% DM) and lab lab (Lablab purpureus L. Sweet, cv. Highworth-3.0% DM); and anhydrous ammonia (NH3 3.0% DM). The chemical treatment increased the pH and the in vitro digestibility of the hays Ammoniation did not affect ADF and cellulose contents. The NDF, hemicellulose and lignin contents decreased due to ammoniation with NH3. The urea utilization had the same efficiency that anhydrous ammonia on the hemicellulose content of the hays. The use of an external source of urease did not affect the urea treatment efficiency. The evaluation of the chemical characteristics of the forages, as the dry matter content, buffering capacity, and urease activity can be helpful on the prediction of their responses to the ammoniation.
anhydrous ammonia; buffering capacity; chemical composition; tropical grasses; urea
