Effects of phonologic growth stages on forage quality of four rangeland species in Sari plain region

Determining forage quality is an important factor for proper management of rangelands. Information on forage quality of key species is necessary to assess rangelands to supply the feedstock requirements of livestock which depends on growth season and rangeland grazing capacity. This research was conducted in Sari plain region at three growth stages of four rangeland species, including white clover (Trifolium repens L.), sainfoin (Onobrychis sativa), snail medic (Medicago scutellata), and common alfalfa (Medicago sativa) which have three life forms. The samples were randomly collected at three phenological growth stages (vegetative growth, flowering and seed formation). Then chemical analysis was accomplished to determine the contents of crude protein (CP), acid detergent fiber (ADF), dry matter digestiblity (DMD) and metabolic energy (ME). The results showed that the effect of phenological growth stages on forage quality indicators including cell wall free hemicelluloses and digestible dry matter were significantly higher than other indicators. The percentage of ADF on sainfoin and white clover species increased in the later compared to earlier growth stages. Percentage of DMP significantly reduced during phenological stages in these species. White clover had the most nutritive value than other species in beginning of growth and flowering stages.