Favorability of forage quality of important range species in Arshagh semi steppe rangelands

Information of forage quality index are of paramount importance in animal and rangeland management. To that end quality of important common forage spices in Arshagh semi steppe rangelands، was determined. In the present study، 5 rangeland species including; Stipa hohenackeriana، Kochia prostrate، Astragalus brachyodonuts، Artemisia fragrans، Falcaria vulgaris were sampled at 3 different phenological stages (vegetative، flowering and seeding) in 2009. In each stage، 3 samples and for each sample 9 plant was harvested. Then index amounts for forage quality were calculated. Results show that; The mean values of crude protein (CP) and dry matter digestible (DMD) in phonological stages has well desirability and was more than need of one animal unit maintenance، but mean value of metabolism energy (ME) in vegetative stage was more than critical level and in flowering and seeding stage was less than its critical level for need of maintenance of single animal unit. 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 years.