Abstract

Information on different rangeland plants’ nutritive values at various growth stages is important in rangelands management. This information helps rangeland managers to choose proper grazing times to achieve higher animal performance without detrimental effects on the rangeland vegetations. Effects of various plant parts’ growth stages and vegetation types on reserve carbohydrates and forage quality indicators were investigated during 2009 and 2010. Plant samples were collected from natural rangelands in Iran with completely randomized block (CRB) design. The species included, two grass species (Secale montanum and Festuco ovina), two forbs (Lotus corniculatus and Sanguisorba minor) and two shrubs (Kochia prosterata and Salsolarigida). Aerial plant parts’ samples were oven-dried at 80°C for 24 h, then analyzed for soluble carbohydrates, crude protein (CP), acid detergent fiber (ADF), dry matter digestible (DMD) and metabolizable energy (ME). Results showed that plants at the seedling stage had more reserve carbohydrates and from the three vegetation types (grass, forbs, and shrub), forbs contained more soluble carbohydrates as compared to the other two (grasses and shrubs). Differences in soluble carbohydrate contents of different species at various growth stages in 2 years were statistically significant. The forage quality indicators (CP, ADF, DMD and ME) in different species, in various vegetation types, in the 2 years were statistically significant, except for the CP.

Key words: Phonological stage, forage quality, protein, fiber.