摘要：Nutritional characteristics of the feeds should be determined to meet there quirements of animals. The current experiment was conducted to determine the potential nutritive value, gas and methane production of Astragalus argaeus plants harvested at three different maturity stages. Maturity stage had a significant effect on chemical composition, gas and methane production, metabolisable energy (ME), organic matter digestibility (OMD) and mineral content.Neutral detergent fiber (40.30-52.32%) and acid detergent fiber (21.61-32.59%) contents increased with the progress of maturity, whereas crude protein (15.52-12.42%), condensed tannin (0.39-0.07%), ether extract (1.44-1.07%) and crude ash (19.47-10.75%) contents decreased. The gas (42.1027.75 ml) and methane (6.93-4.36 ml) production at 24 h incubation, metabolisable energy (8.81-6.52 MJ/kg DM) and organic matter digestibility (60.98-44.82%) decreased with the progress of maturity. Maturity stages did not have any significant effects on Co contents. The highest Mn, Fe, Cu, Ni, Zn, Mg and K contents were obtained from pre-flowering stage whereas the highest Cd and Ca content was obtained from seeding stage. Co and Ni contents of Astragalus argaeus hay were above the toxic threshold levels and other element contents were below.The potential nutritive value of Astragalus argaeus hay decreased with increased maturity but it appears that Astragalus argaeus plant could be grazed as a reliable feed source for ruminants during summer in steppes provided that special attention is paid to heavy metal content.
关键词：Astragalus argaeus;nutritive value;in vitro gas and methane production;mineral content
