Abstract 498

Dixon,-RM; Escobar,-A

Inst. Produccion Animal, Facultad de Agronomia, Univ. Central de Venezuela, Maracay, Venezuela.

Tropical-Animal-Production. 1984, 9: 1, 53-61; 12 ref.

Mature chopped Pennisetum purpureum forage was treated with water alone, with NaOH 2.4 or 4.8% of forage dry matter (DM), with urea 2.4 or 4.8% without or with ground Canavalia ensiformis seed, or with mixtures of urea 2.4% and NaOH 0.95, 1.9, 2.9, 3.8 or 4.8%. The treated forage was ensiled in plastic drums for 30 days after which the pH, concentration of NH3 and DM digestion in nylon bags exposed to rumen fermentation for 24 h were then measured. After 30 days the mixture was acidic to neutral in all silos. All of the added urea was hydrolysed to ammonia, but there was no effect of urea treatment on DM digestibility. There was a linear increase in DM digestibility with added NaOH; DM digestibility was increased by 12% with 4.8% NaOH and by 16% with the mixture of 4.8% NaOH and 2.4% urea. In Experiment 2, 1.8, 3.6 and 5.3% NH4OH, NaOH, Ca(OH)2 or 1:1 mixtures of NaOH and Ca(OH)2 were applied to forage and ensiled for 44 days. There was no effect of NH4OH on DM digestibility; control forage was ensiled with water. There were linear increases of up to 19% in DM digestibility due to treatment with NaOH or Ca(OH)2. NaOH tended to be more effective than Ca(OH)2. In a 3rd experiment, responses were similar.