PSVI-9 Effects of Hibiscus sabdariffa on dry matter disappearance and greenhouse gas emissions in dairy cow diets

Abstract Greenhouse gases (GHG) emission from agriculture (24%) are an important contributor to climate change. Livestock accounts for an estimated 80% of total agriculture emissions, making abatement of GHG emission from livestock a high-priority challenge facing animal nutritionists. These gases are produced because of ruminal fermentation of feeds resulting in a significant contribution of GHG from this sector. There are potential strategies to reduce GHG emissions in ruminants such as improved farming systems, forage quality, animal genetics, feed additives and dietary fats inclusion, modified microorganisms, etc. The current study evaluated an important nutraceutical plant, Hibiscus sabdariffa L. (Malvaceae), for its ability to modulate rumen function to increase dry matter digestibility and reduce GHG emission in dairy cows. The calyces of H. sabdariffa at six different doses (0, 1, 2, 4 and 6 g/head) were used in an in vitro batch culture study. Two dairy diets—alfalfa hay and total mixed ration were used as substrates. Inoculum was collected from 2 cannulated dairy cows from the CAES farm and substrates were incubated for 3, 6 and 24 h. Gas production was measured and analyzed for methane, carbon dioxide, hydrogen sulfite and ammonia. H. sabdariffa reduced (P < 0.05) methane production in all the alfalfa hay treatments except at 6 g/head inclusion level. No effect (P > 0.05) was noted for TMR treatment. We observed small numerical reduction in carbon dioxide in all but two inclusion levels. About 25% increase in dry matter digestibility was noted for 4 g/head treatment. Further studies are planned to validate results.