Document Type : Research Paper
Authors
Abstract
In the present study, the forage quality of five range species including Astragalus remotijugus, Hordeum bulbosum, Onobrychis melanotricha, Phlomis persica, and Picris sterigosa were evaluated in 2010. At each phenological stage, three samples and for each sample, at least five species were cut randomly. Then samples were air-dried and grinded. The amount of crude protein (CP) and acid detergent fibers (ADF) was measured in laboratory then dry matter digestibility (DMD) and metabolism energy (ME) was evaluated by the proposed equations.Our results showed that the interaction effect of species and growth stage was significant for the forage quality traits studied (p<0.05) and the forage quality of the species study species varied at different growth stages. The highest amount of crud protein (18.17 %) was related to the vegetative growth stage of Phlomis persica, and the lowest amount was related to the seeding stage of Hordeum bulbosum. The highest level of digestibility (66.44 %) and metabolisable energy (9.30 MJ/KgDM) was measured for the vegetative growth stage of Onobrychis melanotricha, and the lowest amount of digestibility (42.65 %) and metabolisable energy (5.25 MJ/KgDM) was related to the seeding stage of Picris sterigosa. It is concluded that vegetative growth and flowering stages are able to provide the protein requirements and metabolizable energy for the animal unit; however, the final stages of growth is unable to meet the protein requirements, leading to reduced animal performance in the rangeland.. Therefore, the use of supplements in the final stage of growth is recommended for livestock maintenance and the economic efficiency of herd.
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