The aim of this study was to compare chemical composition, relative feed values, and in vitro true digestibility of the giant fennel (Ferula communicus L. -F), helis (Prangos ferulacea L. -H), gum- tragacanth (Astragalus microcephalus WILD. -G) and leaves oak tree (Quercus robur L. -O), a naturally growing plant on the high- altitude plateaus of the Eastern Anatolia, with those of alfalfa. In vitro true digestibilities (IVTD) of roughages were determined with the Ankom DaisyII incubator. In terms of crude protein (CP) content, the lowest value was determined in H herb with 7.35 %, and the highest value was determined in alfalfa hay (A) with 19.28% (p<0.05). G hay had higher acid detergent fiber (ADF) and neutral detergent fiber (NDF) content and O leaves had higher ether extract (EE) and condensed tannin (CT) content. While the lowest IVDMD were found in G hay (42.91%) and O leaves (56.22%) with the highest cell wall structural components and CT content, the highest digestibility value was determined for F (70.47%) and A (71.60%) (p<0.05). Considering the analyzed parameters, it can be said that F hay is more suitable for ruminant feeding than other roughages.