EFFECT OF INCORPORATING ROLLED BARLEY IN AUTUMN-CUT RYEGRASS SILAGE ON EFFLUENT PRODUCTION, SILAGE FERMENTATION AND CATTLE PERFORMANCE

Direct-cut silage was made in mid-October 1985 from established swards of predominantly hybrid ryegrass (Lolium perenne x Lolium multiflorum). The crop contained 161 g dry matter/kg and 94 g soluble carbohydrate/kg and was ensiled in bunker silos with (i) no additive (control), (ii), formic acid (5 litres/t) or (iii) addition of 45 kg rolled barley per tonne of grass in silo. The inclusion of barley reduced effluent production to 27 litres/t of ensiled grass compared with 51 litres for the control and 60 litres for the formic acid treatment. Losses of DM in effluent were small but total in-silo DM loss was reduced from 25% for the control to 11% by formic acid and to 13% by inclusion of barley. DM content of the silage containing barley was 30 g/kg higher than that of the other silages. Silage treated with formic acid contained least ammonia-N, 6% of the total N, compared with 9% in the barley-added silage and 11% in the control. In vivo assessment in sheep gave metabolizable energy values of 9.8, 10.9 and 11.2 MJ/kg for the control, formic and barley silages, respectively; N retention was higher in the formic acid and barley-added silages. The silages were fed ad libitum to beef cattle for 8 weeks, with a daily feed supplement to the control and formic acid groups to equate barley intakes. Silage DM intake was higher for the barley silage, daily live weight gain per animal was similar for the barley-added and formic acid silages (c. 1 kg), both being higher than the control (0.8 kg). It was concluded that barley inclusion achieved similar improvements in silage quality, in-silo losses and cattle performance to formic acid treatment but with the additional benefit of markedly reducing effluent production.