EFFECT OF FORAGE MATTING ON RATE OF GRASS DRYING, RATE OF SILAGE FERMENTATION, SILAGE INTAKE AND DIGESTIBILITY OF SILAGE BY SHEEP

The effects of forage matting on rate of grass drying and silage fermentation, digestibility, and intake were examined using perennial ryegrass swards. Treatments compared were: forage mats, where grass was processed through a laboratory scale macerator prior to matting and wilting to 228 g dry matter (DM) kg(-1) (FM treatment); unconditioned grass which was direct ensiled at 163 g DM kg(-1) (DE treatment); unconditioned grass which was wilted for the same period as FM to 213 g DM kg(-1) (UC treatment); unconditioned grass which was wilted to 234 g DM kg(-1) (UC25 treatment). All forages were dried on black plastic sheeting. For each treatment a total of approximately 80 kg grass DM was ensiled in seven 290 1 plastic bins for 136 d prior to feeding to wether sheep. A further total of 14 kg grass DM from each treatment was ensiled in twenty-one plastic pipes (152 mm diameter, 762 mm long) to give a total of 84 pipes. Rate of silage fermentation was determined by destructively sampling pipes following 1, 2, 4, 6, 13, 20 and 50 d of ensilage. Over the mean wilting period of 6.9 h, grass from the FM treatment dried significantly faster (P < 0.001) and required less solar energy per unit of moisture loss than unconditioned grass. The rate of grass drying was highly correlated with solar radiation. The FM treatment did not influence the rate or extent of silage fermentation. The intakes and digestibilities of FM, UC and UC25 were not significantly (P < 0.05) different from each other but were higher than for the DE treatment (P < 0.05 for digestibility and NS for intake). In Northern Ireland it is unlikely that there will be sufficient solar radiation to allow forage mats to be made, wilted to a level to prevent effluent production and harvested within one working day. Further work is required to optimize mat-making technology for more rapid drying and to determine the effect of adverse weather on nutrient losses from mats.