Doubts have been expressed about the aerobic stability of whole-crop cereal silages. Urea and ammonia additives have proved effective in controlling aerobic deterioration (Deschard et al., 1988). The aim was to evaluate the effects of two commercially-produced (Finnish Sugar Co. Ltd., Helsinki) cellulase and hemicellulase mixtures (Clampzyme [CLZ] and Deezyme [DEZ]) on fermentation and aerobic stability of winter-sown wheat (cv Brock), harvested at four stages of growth.

The experiment was of 4 x 2 x 4 x 2 factorial design. The crop was direct-cut harvested (precision chopped) and ensiled for 150 days in mini-silos (polypropylene sack enclosed in polyethene sack; 5.0 kg dry matter (DM) of crop; plastic-strip seals). Harvesting was at 4 moisture-content (g DM/kg) stages of growth: cut 1, 300 (heading); cut 2, 400 (mealy); cut 3, 500 (soft/medium dough); cut 4, 650 (hard dough). Enzymes were applied at 4 levels: 0, 0.3, 0.7 and 1.0 1/tonne (t) DM for CLZ and 0, 1.0, 1.3 and 1.7 1/t DM for DEZ. Silos were either evacuated and sealed immediately (IMM) or sealed after 24 h (DEL).