Judul: Penggunaan berbagai absorban dan sumber karbohidrat terlarut air untuk meningkatkan kualitas silase daun rami
Abstrak: Ramie leaves silage qualities improvement by addition 20% W/W FS of absorbance and water soluble carbohydrates (WSC) sources prior to 42 days of ensiling time have been done in two experiments. Experiment-1 examined three types of the additives (cassava meal, pollard and coarse grinding corn) for their capacities to improve physical (color, odor, texture and spoilage), fermentative (pH, protein degradation, organic acid profiles) and utilities characteristics of the silages for ruminants (rumen fermentabilities and digestibilities) in vitro. The silages had bright greenish brown of color, lactic acid odor and firm textures, categorized as highly fermentable and digestible feeds (dry matter digestibility >72%). Compare to other additives, cassava meal produced better silage based on their physical chemical characteristics and drop silage pH faster than other additives. However, high butyric acid and protein degradation proportions in the silage were not seem in line to these data. Coarse grinding corn failed to do its function therefore produced poor silage quality. Second experiment was aimed to confirm the previous results. Five types of additives (cassava meal, pollard, fine grinding corn, rice bran, and cassava extract meal) of the same functions were examined. The results confirmed that cassava meal still produce better ramie leave silages than other additives. However, this time, all additives successes to serve their functions therefore produce good ramie leave silage qualities.
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Judul: Evaluasi Kualitas Nutrien Silase dan Hay Daun Rami dalam Ransum Komplit untuk Ruminansia secara In Vitro
Abstrak: A research to evaluate the effect of ramie leaves silage and hay on ruminant complete mixed ration (CMR) on nutrient content, fermentability, and digestibility by in vitro method have been conducted. There were 7 CMR treatments i.e. P0 (control ration) = 50% napier grass + 50% concentrate, P1 = 30% napier grass + 20% ramie leaves silage + 50% concentrate, P2 = 20% napier grass + 30% ramie leaves silage + 50% concentrate, P3 = 10% napier grass + 40% ramie leaves silage + 50% concentrate, P4 = 30% napier grass + 20% ramie leaves hay + 50% concentrate, P5 = 20% napier grass + 30% ramie leaves hay + 50% concentrate, and P6 = 10% napier grass + 40% hay + 50% concentrate. Both ramie leaves silage and hay increased the CMR digestibility and nutrient content, except the crude fiber. Control ration had a higher crude fiber than silage and hay. The CMR which contain ramie leaves silage had higher nutrient digestibility compared to the other rations. Fermentability of CMR was measured by ammonia concentration, VFA, and gas production. Rations which added with ramie leaves hay (P4 – P6) had a higher gas production whereas rations added with ramie leaves silage (P1 – P3) had a higher rations VFA concentration and gas production compared to P0. Ammonia concentration of rations added with preserved ramie leaves were lower than control, however ammonia concentration in all treatments were in optimal range. Acetate proportion was higher in CMR which contain ramie leaves hay than CMR which contain silage although the nutrients digestibility were lower. Adding ramie leaves silage in rations resulted higher propionate and butyrate proportion than control and rations which added with ramie leaves hay. Either silage or hay ramie leaves can be used up to 40% as napier grass substitute in ruminant CMR. Keywords: Hay, ramie leaves, ruminant, silage
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Judul: Bifurkasi Hopf pada Model Siklus Bisnis Kaldor Kalecki tanpa dan dengan Waktu Tunda
Abstrak: Business cycle model is one of dynamical system models in economic. One of the business cycles model is Kaldor-Kalecki model. Kaldor-Kalecki business cycle model that is written in delayed defferential equations, is a business cycle model that involves gross product and capital stock of a company. In this paper Kaldor-Kalecki business cycle model is analyzed using both nondelay and delay in time of capital stock. By Taylor expansion for the time delayed model, an analysis of stability around the fixed points has been done. Furthermore, by using Hopf bifurcation theorem, it can be shown that there exists periodic orbits and limit cycle. In the nondelayed model, changing the parameter of goods market could lead to the occurrence of Hopf bifurcation and the existence of limit cycle. Similarly, for the delayed model, it has been shown that changing the time delay parameter may result in the occurrence of Hopf bifurcation and limit cycle.
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