Methane Emissions from Ruminant Livestock in Ethiopia: Promising Forage Species to Reduce CH4 Emissions

Abstract

This paper assesses the ability of fodder plants to reduce methane (CH 4 ) emissions while simultaneously improving animal productivity in Ethiopia. Enteric CH 4 emissions from ruminants in Ethiopia increased by 12% or ≈ 6197 Gg CO 2 -eq. in 2017 compared to the year 2011. In this study, six tropical multipurpose forages (Leucaena leucocephala (Lam.) de Wit, Moringa stenopetala (Bak.f.) Cuf., Sesbania sesban (L.) Merr., Cajanus cajan (L.) Millsp., Crotalaria juncea L., and Lablab purpureus L.(Sweet)) and maize stover were characterized in terms of chemical composition, in vitro CH 4 production, and CH 4 concentration (%). The objective was to identify forages with low CH 4 production potential but with adequate forage quality. The forages differed significantly in chemical composition and in enteric CH 4 emission. The dry matter (DM), ash, crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF), and acid detergent lignin (ADL) ranged between 89.4-95.4%, 6.08-12.5%, 3.3-30.7%, 20.4-76.0%, 10.8-44.8, and 2.9-14.1%, respectively. All forage plants, except maize stover, contained high CP content above a threshold value (i.e., 7%). Cajanus c. generates the lowest amount of CH 4 (32.83 mL/0.2 g DM incubated). CH 4 concentration (%) was used as a potential indicator to determine the capacity of a plant to lower CH 4 production. Among the studied species, L. purpureus showed the highest CH 4 reduction potential (16%) followed by C. juncea (23.45%), M. stenopetala (24.2%), and L. leucocephala (25.5%). M. stenopetala was the most frequently preferred by the farmers followed by C. juncea and L. leucocephala. We concluded that M. stenopetala, C. juncea, and L. leucocephala can be promoted as valuable feed resources for ruminants while simultaneously reducing CH 4 emissions.

Effect of Feeding Improved Grass Hays and Eragrostis tef Straw Silage on Milk Yield, Nitrogen Utilization, and Methane Emission of Lactating Fogera Dairy Cows in Ethiopia

“…Estimated enteric CH 4 emission is the by-product of ruminal fermentation via methanogenesis and is thus substantially affected by a range of factors, including dietary components [ 65 ]. Thus, the methane production variation in our study among the dietary treatments might be related to the difference in the proportion of nutrients, such as the high NDF content of the NPH-based TMR [ 11 ]. Specifically, the fermentation of fibrous materials favors the formation of acetate and butyrate which contribute to the production of CH 4 [ 65 ].…”

“…In our study, methane emission per kg of OM intake was lower for the TTS, NGH, and BhH diets than for NPH, thereby indicating that highly digestible roughages are promising means for reducing CH 4 emission. Likewise, cows fed NGH and BhH, followed by TTS, had significantly lower methane output per unit of daily milk yield than NPH diet, showing that the TMR diets containing improved forage species with high CP contents have great potential in mitigating methane emission for climate smart dairy production [ 11 ]. Moreover, the environmental cost of producing NGH and BhH forages should be examined before recommending using this strategy to mitigate CH 4 emissions and urinary N excretion.…”

“…This situation is most severe in countries like Ethiopia, which has a huge livestock population [ 8 ], and farmers typically feed dairy cows arbitrarily, without balancing the diet, thus decreasing potential milk production and increasing methane emission [ 9 ]. Hence, proposing an appropriate feeding regimen that enables the reduction of methane emissions and mitigates environmental N pollution from dairy cattle production remain major concerns [ 6 , 10 , 11 ].…”

“…One potential strategy for better feeding of dairy cows during periods of critical feed shortage, particularly in the dry season, is to use improved forage varieties and enhance the quality of available crop residues [ 12 ]. To this end, supporting the traditional feed resources with planted forages appears to be a plausible and sustainable solution [ 11 ]. This situation encourages the cultivation of suitable and adapted improved forages to the tropical regions, such as Napier grass ( Pennisetum purpureum ) [ 13 , 14 ] and Brachiaria hybrid (CIAT 36087) Mulato II grasses [ 15 ], to fulfill the nutrient requirements of dairy cows for milk production [ 16 ].…”

Climate Change Mitigation in Livestock Production: Nonconventional Feedstuffs and Alternative Additives

“…However, some producers in developing countries are not able to afford these alternatives. Otherwise, methane production in ruminants in developing countries is directly correlated to a poor quality in feedstuffs offered to livestock, by decreasing the efficiency and productivity for productive unit [72]. In this way, the strategies that producers and researchers in developing countries use imply the production of improved forage sources which is cheaper than the acquisition of some supplements.…”