The impact of hydrolyzing and oxidizing agents on chemical composition and digestibility of various high - fibre forages

Urea (U), sodium hypochlorite (H) and sodium chloride (S) alone or combined were applied upon high - fibre forages (HFF) in three experiments. Experiment (Exp) I: tall wheatgrass (TW), weeping lovegrass (WL), deferred sorghum (DS) and barley straw (BS) as substrates were untreated (U0) or treated with 4 g 100 g-¹ DM (U4), and stored for 45 days. Within each forage, CP and IVDMD were increased by U4 (p minor sign 0.01). Exp II: TW was treated with U and H: U (as in Exp I) and H (at 0, 0.25, 0.50, 0.75 and 1 g active Cl 100 g-¹ DM), alone or combined. The interaction U*H was significant for ADF, ADL and CP. For U4+H0.25 ADF and ADL decreased (p minor sign 0.01). For U0, ADL was reduced from H.025 through H1.00 (p major sign 0.05). U4 increased IVDMD and CP (p major sign 0.01). Exp III: oat straw (O) was treated with U0 and U4, H0 and H1, S0 and S4 (4 g S 100 g-¹ DM), including all combinations at 3 storage times (T = 10, 20 and 30 days). Interactions U*S*H*T for ADL, U*H*T for NDF and CP and S*H*T for IVDMD (p major sign 0.05) were found. ADF was reduced by U4, H1 and S1 (p major sign 0.01). The greatest decrease (4.5 per cent) was with U4. Principal components analysis showed U4S4H1 highly related to IVDMD for all T. All treatments had little or no impact on NDF, ADF and ADL content. Lower quality forages had greatest improvements in digestibility and N-retention.