Effects of urea and aqueous ammonia treatment on the nutritive value of triticale straw

摘要

A study was conducted to investigate changes in nutritive value of triticale straw (TS) treated with urea and aqueous ammonia. TS was chopped into pieces, approximately 2 cm in length. Solutions of feed grade urea and aqueous ammonia were applied to 800 g dry matter (DM) of chopped TS at rates of 0, 1.5, 3.0 and 4.5% (w/w). The chemicals were applied as aqueous solutions which added 800 g of water/800 g of TS DM, thoroughly mixed, stored in plastic containers and kept for 45 days at ambient temperature (22-25 degrees C). There were four replicates of each treatment. Chemical composition and in vitro digestibility of test materials were determined. The amounts of pH, crude protein (CP) and NH3-N increased (P<0.05) when urea and aqueous ammonia were applied at all rates. As a point of CP, the rates of 1.5 and 3.0% in urea-treated TS (UTS) were equivalent to the rate of 3.0 and 4.5% in aqueous ammonia-treated TS (ATS). Neutral detergent fiber (NDF) and acid detergent fiber (ADF) content decreased (P<0.05) when urea and aqueous ammonia were applied at rates of 3.0 and 4.5%. There was a tendency for treatments to decrease acid detergent lignin (ADL), but the reduction was not significant. UTS had higher in vitro digestibility of DM (IVDMD), organic matter (IVOMD) and OM in DM (IVDOMD) than ATS. As a point of IVDMD, the rate of 1.5% in UTS treatments was equivalent to the rate of 3.0% in ATS treatments. Feed grade urea and aqueous ammonia can improve chemical composition and in vitro digestibility of TS, but effects of urea were better than those of aqueous ammonia.