Forage quality of important range species in Pashaylogh-e-Maravetapeh rangeland ecosystem in Golestan province

Information regarding forage quality index is of paramount importance in animal and rangeland management. Hence, the quality of important common forage species in Pashaylogh-e-Maravetapeh rangelands was determined. In the present study, 18 rangeland species were sampled at three different phenological stages (vegetation, flowering, seeding) in 2009. All of these species were among the most important plant types of the study site. Forage quality indexes namely crude protein (CP), acid detergent fiber (ADF), dry matter digestibility (DMD) and metabolisable energy (ME) were determined to meet animal maintenance requirements. Analysis of variance was used to compare the indexes among species and different growth stages. Specific differences were evaluated using Duncan's test. The results showed that the average crude protein for vegetation, flowering and seeding stages were 17.70, 14.91 and 8.96%, respectively. However, it was the highest in the phenological stages and even lower than the critical level (7.0%) to meet an animal unit maintenance requirement. Average dry matter digestibility values for different phenological stages were 68.01, 64.89 and 55.84% with values higher than the critical amount (50%) for all phenological stages to meet animal maintenance requirements. Metabolism energy in vegetation, flowering and seeding stages were 9.56, 9.03 and 7.49 Mj/Kg/DM respectively with higher values for vegetation and flowering stages and values even lower than the critical level (8Mj) to meet an animal unit maintenance requirement in seeding stages. This suggests that the desirable quality of pasture forage at different times of grazing is not the same and the determination of daily animal unit requirements based on forage quality is needed. It is clear that forage quality varies as the weather changes, but since determining forage quality is costly, the results of this research can be used to estimate animal requirements throughout the year.