Effect of leguminous tree leaves as nitrogen additive to pennisetum purpureum silage

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Date

1999

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Publisher

Sokoine University of Agriculture

Abstract

A study comprising of two experiments was conducted to investigate the effectiveness of three leguminous tree leaves as nitrogen additive (NA) in presence or absence of molasses (as WSC additive) on fermentation and nutritive value of napier (Pennisetum purpureum) silage. Gliricidia sepium, Leucaena leucocephala and Sesbania sesban leaves were used in experiment I while L. leucocephala leaves was used in experiment II. Polyvinyl chloride (PVC) cylinders (1.9xl0’2m3) were used as laboratory silos for experiment I and earth pit silos (Im3) for experiment II. A 2 x 3 x 3 factorial experiment which comprised of fourteen treatments was adopted in experiment I. Napier grass was ensiled in combination with leaves from G.sepium, L. leucocephala and S.sesban as NA. Each combination received three levels of NA (0, 15 and 30% w/w) and two levels of molasses (0 and 3% w/w). A 2 x 3 factorial experiment that comprised of six treatments was adopted in experiment II. One combination in experiment I was ensiled in pilot scale silos, where L.leucocephala was chosen as (NA). Same levels of inclusion of Leucaena and molasses in experiment I were used in this experiment and the grass alone without and with molasses served as contro. The effect of molasses, NA type, NA inclusion level and interactions were observed in experiment I while the effect of molasses and NA inclusion level as well as the interaction between the two were observed in experiment II. Parameters observed in both experiments were sensoric tests, dry matter, chemical composition, in vitro dry matter and organic matter digestibility. Diy matter losses and acceptability test were observed in the second experiment only. In experiment I, addition of molasses and combination of molasses and NA inclusion level improved aroma of the silages. Nitrogen additive types and inclusion levels had no significant (P > 0.05) effect on sensoric qualities of the napier silages. Molasses addition improved dry matter, chemical composition and digestibility of the napier silage. Addition of Leucaena increased DM, CP, NDF, ADF and lowered IVDMD and IVOMD as compared to addition of Gliricidia and Sesbania. Inclusion of 15 and 30 percent NA improved silage DM, chemical composition and digestibility. Combination of molasses and NA type had significant (P 0.05) improvement on WSC, ADF, IVDMD and IVOMD while combination of molasses and NA inclusion level had significant (P < 0.05) improvement on WSC, NDF, IVDMD and IVOMD. The NA types at 15 and 30% inclusion had more improvement on DM, chemical composition, IVDMD and IVOMD than 0% inclusion level. All NA types at 15 and 30% inclusion levels had higher CP, WSC, IVDMD, IVOMD and lower NDF than the control, 30% Gliricidia and 30% Sesbania being the highest among the combinations. Fermentation products were significantly (P < 0.05) improved by addition of molasses and nitrogen additives. Combinations of NA with molasses gave better fermentation quality than those without molasses. In experiment II, molasses addition improved aroma of the silage however, it didn't affect appearance and texture. Sensoric qualities were neither affected by NA inclusion level nor the combination of molasses and NA level. Water soluble carbohydrates, ADF, IVDMD and IVOMD were improved by molasses addition. However, in this experiment, DM, CP, ash and NDF were not improved by addition of molasses. The CP, IVDMD and IVOMD increased with increasing NA inclusion level while NDF and ADF decreased with increasing NA inclusion level. The combination of molasses and NA inclusion level had significant (P < 0.05) improvement on WSC, ADL and IVDMD. Fermentation products were improved by both molasses and NA inclusion. However, they were not affected by the combination of molasses and NA inclusion levels. Dry matter losses were significantly lowered by molasses addition (18.5% vs 20.7%). The DM losses decreased with increasing NA inclusion (16.7, 18.9 and 23.3 percent for 30, 15, and 0 percent NA inclusion, respectively). The combinations of molasses and NA inclusion have the DM losses ranged from 16.6% to 27.0%. The intake rate was higher in molassesed than unmolassesed silage. It was also higher in 30 and 15 percent NA levels than 0% NA. The combination of molasses and NA levels had significant effect on intake rate, 15NA+, 30NA+ and 30NA‘ having higher intake rate than other combinations. It was concluded that 30% NA inclusion could be used to conserve well silage of napier grass. Further findings are required to establish the NA inclusion level in other common grasses such as Guatemala grass (Tripsucum laxurri) and Guinea grass (Panicuni maximum).

Description

Masters of Science in Agriculture

Keywords

Leguminous tree leaves, Nitrogen additive, Pennisetum purpureum silage

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