Ensiling of whole-crop wheat with cellulase-hemicellulase based enzymes. 2. Effect of crop growth-stage and enzyme on silage intake, digestibility and live-weight gain by steers

Whole-crop winter wheat was harvested at the mealy-ripe and hard-dough stages of grain development corresponding to crop dry matter (DM) contents of 427 g DM kg−1 and 678 g DM kg−1 respectively. Crop from each harvest was either untreated or treated with one of two enzyme additives (Clampzyme or FSO2) and then ensiled for at least 60 days, in 7 t capacity bunker silos. Clampzyme was applied at 667 ml t−1 DM and FSO2 at 1000 ml t−1 DM. The six silages were fed individually and ad libitum to 270–300 kg live weight (W) Hereford × Friesian steers over 56 days [d], using 8 animals per silage. Steers were also fed 0.5–0.8 kg d−1 of soyabean-mineral supplement. Digestibility was measured by total collection of faeces using 5 steers per treatment. lages were well-preserved. For the parameters measured, there was no interaction (P > 0.05) between crop growth stage and enzyme treatment. Crop growth stage did not affect (P > 0.05) silage intake (mealy-ripe, 25.5 g DM (kg W d)−1; hard-dough, 25.3 g DM (kg W d)−1). Both diet organic matter digestibility (P < 0.05) (694, 665 g kg−1) and growth rate (P < 0.01) (0.9, 0.8 kg d−1) were higher in steers fed mealy-ripe compared to hard-dought silage. Enzyme additives did not affect (P > 0.05) intake, digestibility or growth rate.