عنوان مقاله [English]
Information of forage quality index are of paramount importance in animal and rangeland management. To that end quality of important common forage spices in Ghareh Bagh semi steppe rangelands, was determined. In the present study, 6 species were sampled at three different phenological stages (vegetative, flowering and seeding) in 2009. All species were belonged to most important plant type of study site. Forage quality index namely; crude protein (CP), acid detergent fiber (ADF), dry matter digestible (DMD) and metabolisable energy (ME) were determined to meet animal requirements in maintenance condition. Analysis of variance was used to compare the index among species and different growth stages. Specific differences were evaluated by Duncan’s test. The results showed that maximum value of crude protein (10.20%) belonged to Teucrium polium and maximum value of dry matter digestibility (55.01%) and metabolisable energy (7.35 Mj/Kg/DM) were belonged to Helichrysum plicatus. The minimum value of crude protein (7.07%), dry matter digestiblility (46.13%) and metabolisable energy (5.84 Mj/Kg/DM) recorded for Festuca ovina. Average crude protein values for different phenological stages were 13.22, 8.13 and 5.03% with higher value for vegetative and flowering stages and with values lower than critical amount (7%) to meet animal maintenance requirements in seeding stages. Average dry matter digestibility values for different phenological stages were 58.07, 49.55 and 43.08 with higher value for vegetative stage and with values lower than critical amount (50%) to meet animal maintenance requirements in flowering and seeding stages. Metabolisable energy in vegetative, flowering and seeding stages were 7.87, 6.42 and 5.32 Mj/KgDM espectively with lower than critical level (8Mj) to meet a animal unit maintenance requirement. This suggests that desirable quality of pasture forage at different times grazing is not same and determination of daily animal units requirement based on forage quality is needed. It is clear that forage quality is changed with variation of weather, but due to the expense of determination forage quality is very high, can use the results of this research for estimate of animal requirement in different yearsKeywords: forage production, rainfall and temperature variables, arid rangeland, protected area of Kalmand .