Their pioneering study, which was funded by the Swedish International Development Cooperation Agency (SIDA), analyzed over 30 ruminant feed samples from indigenous plants, grasses, crop residues, and agro-industrial by-products.
Ethiopian farmers could stand to benefit from these insights, as methane-reducing feeds would not only lessen their environmental footprint but could also improve livestock productivity, said the team.
The analysis revealed that local trees, shrubs, and herbaceous plants produce significantly lower methane (CH4) emissions than grasses and other traditional feed sources.
These findings open new doors for eco-friendly feed solutions that can support smallholder farmers and contribute to climate-resilient agriculture in Africa, according to the researchers.
Samples from indigenous plants like Trifolium acaule and Acacia nilotica showed some of the lowest methane outputs, making them attractive choices for reducing livestock emissions, they found. For comparison, local plants averaged methane yields between 3.1% and 16.9% of total gas output, whereas grasses and crop residues showed higher methane yields.
Additionally, certain agro-industrial by-products, such as brewer's spent grains and local beer residues, also demonstrated lower methane production, further expanding options for greener livestock feed, noted the researchers.
Condensed tannins
With indigenous plants also featuring condensed tannins (CTs), known to inhibit methane production in livestock digestion, these findings point to the potential of CTs in reducing emissions even further, said the team.
“Data obtained in the present study indicated a general decrease in CH4 yield at higher CT levels, particularly at elevated soluble CT concentrations. Trifolium acaule had the highest soluble CT content, resulting in the lowest in vitro CH4 yield, possibly due to inhibitory effects of CTs on protein degradation.”
However, feedstuffs with very high CT content should be avoided, as they can impair productivity in animals, cautioned the researchers.
And the study’s extensive data on nutrient content and methane output for local feed resources provide a valuable resource for scientists, policymakers, and farmers, helping them design effective, low-emission rations that meet livestock nutritional needs, they added.
Source: Animal Feed Science and Technology
Title: Methane production from locally available ruminant feedstuffs in Ethiopia – An in vitro study
Authors: W Bekele et al
