Assessment of the nutritional value of Gundelia tournefortii during its growth stages as a key element in the Senowbar rangeland ecosystem, Northeast of Iran

Abstract

To achieve sustainability and land degradation neutrality in rangeland ecosystems, understanding the growth stages of key plants to develop land management and conservation plans is vital. This study was conducted to determine the nutritional value of Gundelia tournefortii and its changes during different growth stages as one of the most dominant rangeland plants in Khorasan Razavi province, NE of Iran. The plants were randomly sampled in three stages of growth (vegetative, flowering and seeding) in the Senowbar rangeland and eventually moved to the laboratory for chemical analysis. Results showed that crude fiber and acid-detergent fiber and neutral-detergent fiber increased and dry matter, crude protein, ether extract decreased. Ash, Ca, P, K and Na decreased during plant matured; furthermore, these changes were statistically significant (Duncan’s test, 99% and 95%). Dry matter intake, digestible dry matter and relative feed value decreased during growth, which was statistically significant (p < 0.01). The metabolizable energy of Gundelia tournefortii during growth periods reached values of 11.77, 11.58 and 10.46 Mj/Kg, respectively. Also, organic matter digestibility showed a similar decreasing trend. It is concluded that the best time to harvest Gundelia tournefortii from rangelands and to feed is the vegetative period dated from March to April, so harvesting during this period does not prevent seeding.