The biomass production and nutritive value of the natural pasture of Umbulo Wacho watershed in Southern Ethiopia were studied. The upper and medium altitudinal zones had an open area and areas closed for 2, 3 and 4 years and the lower altitude had an open area and an area closed for 2 years. In each of the open and closed areas, three sites were selected (9 in open, 21 in closed) at each of which exclusion cages (30) were fixed. The re-growths of forage samples were cut at 30 days interval from May up to November from the exclusion cages. The overall dry matter (DM, %), organic matter (OM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL), ash, calcium (Ca) and phosphorus (P) contents of the forages were 30.