تعیین ارزش غذایی و تجزیه‌پذیری ماده خشک و دیواره سلولی گونه astragalus crenatus طی مراحل مختلف فنولوژیکی درمراتع هیر- نئور استان اردبیل

پس از آماده ای نیز به روش آزمایشگاهی و با استفاده از دو راس گوسفند نر نژاد مغانی دارای فیستوله شکمبه ا ی تعیین شد. نتایج نشان داد از لحاظ قابلیت هضم و تجزیه پذیری ماده خشک، ماده آلی، دیواره سلولی و دیواره سلولی منهای همی سلولز سایت ارتفاعی دوم به طور معنی داری بیشتر از سایت یک بود (0.01>p). نتایج نشان داد در هر دو سایت، مرحله رشد رویشی دارای قابلیت هضم شکمبه ای، بعد از شکمبه ای و خاکستر بیشتر و دیواره سلولی، دیواره سلولی منهای همی سلولز و ماده آلی کمتری نسبت به سایر مراحل رشد داشت. بنابراین، پتانسیل تجزیه پذیری ماده خشک گونه در مرحله اول رشد بیشتر بوده و با بلوغ گیاه ارزش غذایی آن برای دام های چراکننده کاهش می یابد، در نتیجه بهترین زمان چرا با توجه به این گونه در منطقه، حداکثر اواخر بهار می باشد. همچنین در مطالعات ارزیابی ظرفیت و مدیریت مراتعی که گونه مورد مطالعه گسترش دارد، می توان از این نتایج استفاده کرد.

Determination of nutritional value and degradability of dry matter and cell walls of Astragalus crenatus Schult at different phenological stages in Hir-Neor rangelans of Ardabil province

This study was conducted with the aim of determination of chemical composition, degradability fractions and nutritional value of Astragalus crenatus Schult. Two sites with different elevation ranges (15001700 and 19002100 meters from sea level) were selected to collect the data in highlands ranges of Hir to Neor, Ardebil County. The data sampling was carried out in three phenological stages (vegetative growth, flowering and seeding stages). Plant samples were analyzed and their NDF and ADF were measured using Van Soest method. AOAC common lab methods were used to measure plant samples chemical composition. Ruminal degradability of samples was determined by in situ technique (e.g. two ruminal cannulated Moghani rams). The results showed that digestibility and degradability of dry matter, organic matter, NDF and ADF of samples from the site located in 19002100 meters from sea level ranges were significantly higher than the site in lower site (plt;0.01). Moreover, the analysis of the collected samples showed that the NDF and ADF values in form of percentage of dry matter for species in higher elevations range sites were higher. The dry matter contents of plant samples differed significantly in various phenological stages (plt;0.01). Results showed that the plant samples in vegetative stage had the highest ash and ruminal and postruminal digestibility in both sites. The plants in vegetative stage had lowest NDF, ADF and organic matter content compared to the other phenological stages. In conclusion, the degradability of dry matter of the species in vegetative growth stages was more than other stages, indicating that the nutritional value of plant species is reduced in flowering and seeding stages. It can be concluded that late spring is the best time for grazing this species and it can be considered in grazing management plans of the study area.