Chemical and biological treatment of cotton gin trash for fattening Santa Ines lambs

Abstract Two experiments were used to evaluate the effects of using cotton gin trash (CGT) treated with urea and exogenous fibrolytic enzymes (EFE) on feed chemical composition, in vitro dry matter digestibility and gas production (Trial 1), and apparent in vivo digestibility, intake and growth performance of feedlot Santa Ines lambs (Trial 2). The Trial 1 used a completely randomized 2 × 4 factorial design with four replications of treating CGT with urea (0 and 6%) and EFE (0, 2, 4, 6 g/kg; 75% cellulase, 25% hemicellulase). The Trial 2 used a complete randomized design with 8 replications to evaluate the use of CGT treated with 6% urea and one of four EFE concentrations (0, 2, 4, 6 g/kg) in 50% concentrate and 50% CGT diets; the control diet contained untreated CGT. In Trial 1, there was interaction between urea and EFE dose for DM, EE, ADF, TN, and fractions A and C of nitrogen (P 0.05). Increasing EFE resulted in a linear decrease of NDF, ADF, cellulose, hemicellulose, and lignin. Both urea and EFE increased (P