Potentials of some medicinal plant extracts on digestibility, in vitro gas and methane gas production of Eragrostis curvula forage A.M. Akanmu & A. Hassen Department of Animal and Wildlife Sciences, University of Pretoria, Pretoria, South Africa Introduction One of the major sources of greenhouse gas emission is the enteric methane (CH4) production from ruminants which also results in loss of feed energy to the animal. Medicinal plants have the potential to manipulate rumen microbial ecosystem, which in turn can reduce CH4 production. The anti-methanogenic activities of some medicinal plant extracts (Piper betle, Aloe vera, Carica papaya, Azadirachta indica, Moringa oleifera and Tithonia diversifolia) were studied using the in vitro gas production and digestibility systems. Methodology Plant materials were collected, freeze-dried and extracted with 100% methanol. Dried extracts of each of the plants were re-constituted at the rate of 25mg (0.25%) and 50mg (0.50%) in 100 ml of distilled water. Five mls of each plant extract and concentration were sprayed on 400mg of Eragrostis curvula hay and incubated using standard procedures with 3 replicates for each round, and a total of 4 rounds were executed. Total gas production for each time frame was recorded with pressure transducer attached to a visual display. Methane content in gas produced was determined with gas chromatograph while the in vitro organic matter digestibility (IVOMD) was carried out using 2 stages digestion procedure of Tilley and Terry (1963). a Results Fig.1. Gas production curve at different time s when Eragrostis curvula hay is incubated with plant extracts Fig.2. Methane gas production at different time s when Eragrostis curvula hay is incubated with plant extracts Fig.3. In vitro organic matter digestibility of Eragrostis curvula hay sprayed with different plant extracts Fig.4. The ratio of CH4 to total gas produced (GP) and CH4 emitted per DM digested of Eragrostis curvula hay when sprayed with different plant extracts Fig.5. Significant effect of dosage level on different parameters measured Conclusion Extracts of Moringa oleifera, Tithonia diversifolia, Carica papaya and effectively reduced volume of methane produced without affecting the total gas produced negatively when sprayed on Eragrostis curvula hay before incubating. All the extracts used in this study effectively increased feed digestibility and also reduced the volume of methane gas produced per dry matter digested Dosage at 0.5% significantly reduced methane production at 48hours, CH4 per DM digested at 48hours and increased in vitro DM digestibility Acknowledgment The authors gratefully acknowledge funding from the University of Pretoria, Dept. of Science and Technology and the European communities, 7th framework programme under the grant agreement No. 266018, ANIMALCHANGE project.