Study on the forage quality of five important grasses at different phenological stages in summer rangelands of Golestan province

Determination of forage quality is one of the fundamental factors for suitable management. There are spatial and temporal variations in quality of rangeland species. In this study، forage quality of five important grasses of Bromus tomentellus، Poa angustifolia، Festuca ovina، Agropyron intermedium and Agropyron trichophorum were measured at three phenological stages (vegetative growth، full flowering and seed ripening) in summer rangelands of Golestan province. For this purpose، five replications were randomly selected from each phenological stage. Quality factors of crude protein، ADF، crude fiber، dry matter digestibility and metabolizable energy were measured using in vitro procedures. The results obtained from chemical analysis were analyzed in a factorial experiment at randomized complete block design with SAS software. Results showed that forage quality differed significantly for differentspecies as well as at different phenological stages (p<0. 05). Among studied species، the highest forage quality was related to Bromus tomentellus while the lowest was related to Agropyron trichophorum. The highest and the lowest forage quality were recorded for vegetative growth and seed ripening stages، respectively.