University of Guilan Animal Production Research 2252-0872 6 4 2018 02 20 Effect of different additives on dry matter degradability of mustard forage (Brassica juncea) silage at different phenological stages Effect of different additives on dry matter degradability of mustard forage (Brassica juncea) silage at different phenological stages 39 54 2754 10.22124/ar.2018.6960.1171 FA N. Ghahari MSc. Student of Animal and Poultry Nutrition of Gorgan University of Agricultural Science and Natural Resources, Gorgan, Iran T. Ghoorchi Professor of Animal and Poultry Nutrition of Gorgan University of Agricultural Science and Natural Resources, Gorgan, Iran M. Shahi MSc. Student of Animal and Poultry Nutrition of Gorgan University of Agricultural Science and Natural Resources, Gorgan, Iran M. T. Feyzbakhsh Golestan Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Gorgan, Iran Journal Article 2017 02 20 The aims of the current study were to investigate the <em>in vitro</em> dry matter degradation of mustard (<em>Brassica juncea</em>) forage in various stages of growth, and the impact of molasses and urea on the quality of its silage.In the first trial, chemical composition including dry matter and crude protein in three phenological development stages (vegetative, flowering and soft dough) was measured. Then 1.5 kg of fresh mustard forage were chopped and mixed with molasses and urea and ensiled in the laboratory silos. Different treatments were applied, including control (no additive), 5 or 10% molasses, 0.5 or 1% urea, and 0.5% urea plus 5% molasses. The silages were kept for 45 days at room temperature. Then dry matter of silages was determined, silages appearance, pH and temperature were evaluated. In the second trial, the dry matter degradability of plant and mustard (<em>Brassica juncea</em>) silage were measured by nylon bag method.Advancing plant development and maturity stages significantly (<em>P</em>< 0.05) increased dry matter and decreased crude protein contents. Evaluation of the appearance revealed that the silages, with different levels of molasses, established good and very good qualities. During the ensiling, dry matter was decreased significantly (<em>P</em>< 0.05) and the silages with molasses additive had significantly higher dry matter than the others (<em>P</em>< 0.05). Silage pH was decreased (<em>P</em><0.05) by adding molasses, and increased by urea. Aerobic stability of silages in vegetative and flowering stages was significantly higher than the soft dough stage (<em>P</em><0.05). In all plant developmental phases, the highest percentage of dry matter disappearance, the rapid decomposition, the potential degradability and effective degradability were belonging to silage treated with molasses and the highest part of slow degradability was belonging to the silage without additive. The aims of the current study were to investigate the <em>in vitro</em> dry matter degradation of mustard (<em>Brassica juncea</em>) forage in various stages of growth, and the impact of molasses and urea on the quality of its silage.In the first trial, chemical composition including dry matter and crude protein in three phenological development stages (vegetative, flowering and soft dough) was measured. Then 1.5 kg of fresh mustard forage were chopped and mixed with molasses and urea and ensiled in the laboratory silos. Different treatments were applied, including control (no additive), 5 or 10% molasses, 0.5 or 1% urea, and 0.5% urea plus 5% molasses. The silages were kept for 45 days at room temperature. Then dry matter of silages was determined, silages appearance, pH and temperature were evaluated. In the second trial, the dry matter degradability of plant and mustard (<em>Brassica juncea</em>) silage were measured by nylon bag method.Advancing plant development and maturity stages significantly (<em>P</em>< 0.05) increased dry matter and decreased crude protein contents. Evaluation of the appearance revealed that the silages, with different levels of molasses, established good and very good qualities. During the ensiling, dry matter was decreased significantly (<em>P</em>< 0.05) and the silages with molasses additive had significantly higher dry matter than the others (<em>P</em>< 0.05). Silage pH was decreased (<em>P</em><0.05) by adding molasses, and increased by urea. Aerobic stability of silages in vegetative and flowering stages was significantly higher than the soft dough stage (<em>P</em><0.05). In all plant developmental phases, the highest percentage of dry matter disappearance, the rapid decomposition, the potential degradability and effective degradability were belonging to silage treated with molasses and the highest part of slow degradability was belonging to the silage without additive. https://ar.guilan.ac.ir/article_2754_5f8aa5f51d54e4338d78fd2b74e4c628.pdf