Forage quality changes of seven forbs and grasses species in different phenological stages in Asadly and Sisab rangelands of Bojnord

Measuring forage quality of dominant species is a prerequisite of proper management in rangelands. In this research, nutrient values of seven species were evaluated at three Phenological (vegetative growth, flowering and seed production) stages. In this study, a completely randomized design with five replications was used in Bojnord rangelands. Species included: Sanguisorba minor, Onobrychis transcaspica, Onobrychis radiata, Astragalus brevidens, Melica ciliate, Agropyron repens and Agropyron pectiniforme. The measured forage quality parameters included: crude protein (CP), acid detergent fiber (ADF), dry matter digestibility (DMD) and metabolizable energy (ME). According to results, forage qualities in all of the studied species were higher in vegetative growth than flowering and seed production stages. CP, ME and DMD of the studied species were decreased approaching to the end of growing season, while ADF values were increased. Legumes had higher percentage of crude protein (14.53%) and the lower percentage of ADF (43.91%) in all phenological stages, while perennial grasses had CP and ADF of 8.1% and 54.14% respectively. High and low CP percentages were obtained in Astragalus brevidnes and Agropyron pectiniforme, respectively. According to the results, significant differences were observed among the species and phenological stages for all measured and calculated forage quality factors (p<0.01).