Effect of various growth stages on nutritive value of Stipa capensis in Bushehr province, Iran

This research was carried out to determine the nutritive value of Stipa capensis in various growth stages at three rangeland areas during November 2011 to April 2012. The samples of S. capensis were taken randomly in three stages including vegetative, flowering and maturity (seed production). Samples from each stage of each area were determined for DM, CP, Ash, EE, NDF, ADF, ADL, GE, Ca, P, K, Mg, Na, Fe, Mn, Zn, Cu, DMD, OMD and DOMD. Data were statistically analyzed in a Randomized Complete Blocks Design with three treatments (growth stages) and three blocks (rangeland areas). Results showed that CP, Ash, NDF, ADF and ADL content of S. capensis at different growth stages were significantly different (P<0.05) and CP content of S. capensis decreased with growth advancement but its NDF, ADF and ADL content increased. DM, EE and GE content of S. capensis at three growth stages were not different significantly (P<0.05). Also, P, K, Mg, Zn, Cu, DMD, OMD and DOMD content of S. capensis decreased with growth advancement but its Na increased significantly (P<0.05). This plant in vegetative and flowering stages can supply a great part of protein and energy requirement of different groups of sheep and goat at rangeland areas. Ca, K, Mg, Na, Fe and Mn content of S. capensis at different growth stages were higher than those of  critical limits for sheep and goat; however, the P and Cu content at three stages, and Zn concentration at flowering and maturity stages were less than those of critical limits. Totally, this plant species is suitable for livestock grazing specially at vegetative and flowering stages and could be recommended in similar rangelands.