Determination and comparison of forage quality of cultivated ecotypes of two species of high-yielding herbaceous Astragalus (Astragalus brevidens and Astragalus vegetus)

Forage quality is one of the most important factors that is necessary for proper nutritional management of livestock from rangelands. The most important quality factors of plants are crude protein, ADF, crude fiber, metabolic energy and digestible dry matter. The present study was conducted to evaluate the forage quality of high-yielding herbaceous species (Astragalus brevidens and Astragalus vegetus) grown in Homand Absard Research Station. The studied species are palatable species of rangelands of Khorasan, West Azarbaijan and Kurdestan provinces, which the seeds were collected and cultivated in 2010 at Homand station. In this study, sampling was performed in 2020 in three stages of vegetative growth, flowering and seeding in three replications and qualitative indices were measured. The results showed that the forage quality of these two species (four ecotypes) in the vegetative and flowering stages is higher than the seeding stage. In terms of crude protein content, digestibility and metabolic energy of all 4 ecotypes were very desirable in the vegetative and flowering stages (protein and metabolic energy above 8 and digestibility above 60%) and at the seeding stage. Also, there was no significant difference between the two species in terms of qualitative parameters. The highest amount of crude protein (16.24%) and the lowest amount of NDF (37.36%) belonged to Astragalus vegetus (Diwandare ecotype) in the vegetative stage. Due to the desirability of these two species in all stages of growth, these species can be used for livestock in spring and early summer.