Chemical Composition and In Vitro Digestibility of Some Range Species in Rangelands of Chaharmahal and Bakhtiari Province, Iran

Abstract. Five common range forage including Agropyron intermedium, Bromus tomentellus, Hordeum bulbosum, Cousinia bakhtiarica and Scariolla orientalis, were sampled during three phenological stages, from controlled rangeland stations over five locations in Chaharmahal and Bakhtiari province, Iran. All samples were chemically analyzed for Crude Protein (CP%), in vitro Dry Matter Digestibility (DMD), Organic Mater Digestibility (OMD), Ether Extract (EE), Crude Fiber (CF), total Ash, Neutral Detergent Fiber (NDF) and Acid Dtergent Fiber (ADF). Results for Crude Protein (CP%) showed significant differences between phenological stages in all of species. Maximum CP (15.2%) was found in vegetation stage of Hordeum bulbosum and the minimum (2.9%) was in seed ripening stage. The CF% was significantly different between phenological stages as well as the species. The minimum and maximum values of CF% were found in Agropyron intermedium in Coosinia bakhtiarica, respectively. Similarly, the minimum values of NDF and ADF were found in vegetative stage of Scariolla orientalis and Agropyron intermedium respectively, but the maximum values were obtained in seed ripening stage of Hordeum bulbosum and Cousinia bakhtiarica. The DMD and OMD% showed slightly reduction passing from vegetation to seed ripening stage in most of the species. The highest DMD and OMD% had been observed in vegetation stage of Scariolla orientalis and the lowest were in Bromus tomentellus. It can be concluded that in the early stage of growth, the quality of forage in range species is adequate for livestock production but during that stage, the greatest problem is its lower quantity. By progress of the vegetation stage toward the seed ripening stage, the nutritive value of all species decreased thus grazing animals oppose to nutrient deficiencies.