Chemical composition and in vitro digestibility of Brachiaria decumbens Stapf. hay treated with urea

An experiment was conducted to evaluate the effects of urea treatment on the chemical-bromatologic compounds and in vitro dry matter digestibility (IVDMD) of Brachiaria decumbens hay. The hay were reconstituted with water to get final forage moisture concentration of 30%, and treated with urea at 0, 2, 4, 6, 8, and 10% of the forage dry matter. A completely randomized design with three replicates was used. The material was stored in plastic bags (2kg/plastic bag) for 35 days, and after plastic bag opening, samples were collected to chemical analysis. Hay total nitrogen (TN) concentration increased linearly with increasing urea level. The NDIN/TN and ADIN/TN ratios decreased with increasing urea level. The neutral detergent fiber (NDF), acid detergent fiber (ADF) and cellulose contents decreased due to ammoniation with urea. The hemicellulose and lignin contents were no affected with urea treatment. The in vitro dry matter digestibility (IVDMD) had a quadratic response to the increasing urea level reaching the maximum digestibility of 68.9% at the 7.15% urea level. Urea ammoniation altered the chemical composition and digestibility of the Brachiaria decumbens hay, improving the nutritive value of forage.