COMPOSITION, DIGESTIBILITY AND UTILIZATION OF ENDOPHYTE-FREE TALL FESCUE FED AS GREEN-CHOP OR HAY TO SHEEP

Two lamb digestion trials were conducted using three cultivars of endo phyte-free tall fescue (Festuca arundinacea Schreb.) that had been har vested from paddocks as green-chop forage of initial growth or as regr owth hay. The tall fescue cultivars were Johnstone (JOHN), AU Triumph (AUT) and Kentucky 31 (KY-31), All cultivars within each harvesting me thod contained similar quantities of dry matter (DM) and organic matte r (OM). Both JOHN green-chop and hay contained more crude protein (CP) than the corresponding harvest of AUT or KY-31, Green-chop JOHN conta ined less (P<0.10) acid detergent fiber (ADF) and neutral detergent fi ber (NDF), whereas JOHN hay contained more ADF and NDF than AUT or KY- 31, The DM, OM, CP, ADF and NDF of JOHN green-chop were more digestibl e (P<0.10) than KY-31 or AUT. The same trend existed for hay, but dige stibility of OM and CP did not differ between John and KY-31. The DM, OM, ADF and NDF digestibilities of AUT were greater (P<0.10) than KY-3 1 when harvested as green-chop forage and fed to lambs, No differences in digestibilities of DM, OM, N, ADF or NDF of AUT and KY-31 were obs erved when fed as hay. Ingestion and excretion of N were greater (P<0. 10) in both trials for lambs fed JOHN, However, N retention was simila r for all lambs except for reduced (P<0.05) N retention by lambs fed K Y-31 green-chop forage, It can be inferred from these results that the DM, OM, ADF and NDF contents of Johnstone tall fescue are more digest ible than Kentucky-31 or AU Triumph when fed to sheep as hay or green- chop forage when harvested in a vegetative stage.