RUMEN DEGRADABILITY OF ITALIAN RYEGRASS (Lolium multiflorum, L) HARVESTED AT THREE DIFFERENT GROWTH STAGES IN SHEEP

This experiment was carried out in order to evaluate the chemical composition and rumen degradation characteristics of Italian ryegrass harvested at three different growth stages, i,e. pre-blooming, early-blooming and late-blooming. Degradation values were obtained by incubation of the samples using the nylon bag technique on the rumen of sheep fed a normal diet (Timothy hay with 200 g/d concentrate per head) for 12, 24, 36, 48 and 72 hours, respectively. Neutral detergent fiver (NDF) content was highest at late-blooming (64.4%) while no difference was found among the pre-blooming and early-blooming (49.4% vs 48.3%). However, acid detergent fiber (ADF) content markedly increased from 30.0% at pre-blooming to 35.4% and 46.4% at early-blooming and late-blooming, respectively. Lignin and silica contents also increased as advancing maturity of the grass, Rumen degradation of dry matter (DM) significantly reduced (p < 0.05) as advancing maturity of the grass. Ruman degradation cellulose and ADF at pre-blooming were significantly higher (p < 0.05) than those of early-blooming and late-blooming. However, no significant differences were observed among the early-blooming and late-blooming. With advancing maturity, rumen degradation of NDF and hemicellulose significantly reduced (p < 0.05) at the incubation times.