Inclusion of a tannin-rich legume in the diet of beef steers reduces greenhouse gas emissions from their excreta

Authors: VAN CLEEF, FLAVIA - University Of Florida; DUBEUX, JOSE - University Of Florida; CIRIACO, FRANCINE - University Of Georgia; HENRY, DARREN - University Of Georgia; RUIZ-MORENO, MARTIN - University Of Florida; Jaramillo, David; GARCIA, LIZA - University Of Florida; SANTOS, ERICK - University Of Florida; DILORENZO, NICOLAS - University Of Florida; VENDRAMINI, JOAO - University Of Florida; NAUMANN, HARLEY - University Of Missouri; SOLLENBERGER, LYNN - University Of Florida

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/16/2022
Publication Date: 8/20/2022
Citation: Van Cleef, F., Dubeux, J., Ciriaco, F., Henry, D., Ruiz-Moreno, M., Jaramillo, D.M., Garcia, L., Santos, E., Dilorenzo, N., Vendramini, J., Naumann, H., Sollenberger, L. 2022. Inclusion of a tannin-rich legume in the diet of beef steers reduces greenhouse gas emissions from their excreta. Scientific Reports. 14220(2022). https://doi.org/10.1038/s41598-022-18523-y.
DOI: https://doi.org/10.1038/s41598-022-18523-y

Interpretive Summary: Urine and feces deposited by grazing cattle contribute to the emissions of greenhouse gases, especially nitrous oxide. Nutritional strategies can modify intensity of greenhouse gas emissions, and these may include feeding forage legumes rich in condense tannins. The objectives of this study were to determine the emission of nitrous oxide, methane, and carbon dioxide, as well as the isotopic composition of nitrous oxide from excreta of beef steers fed sericea lespedeza hay (SL). Treatment diets were 0, 50, or 100% inclusion of SL into bermudagrass hay. Gas sampling occurred on days 0, 1, 3, 5, 7, 14, 18, 25, and 32 after excreta application to static chambers for two 32-d experimental periods. There was an effect of day after fecal application for all greenhouse gases. Greenhouse gas emissions, across all gases, peaked during the initial 7 days. This study indicates that feeding SL to beef steers is effective in mitigating the emissions of greenhouse gases from excreta, however further research is warranted to investigate the mechanisms behind these reductions.

Technical Abstract: Urine and feces deposited by grazing cattle contribute to the emissions of greenhouse gases, especially nitrous oxide. Nutritional strategies can modify intensity of greenhouse gas emissions, and these may include feeding forage legumes rich in condense tannins. The objectives of this study were to determine the emission of nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2), as well as the isotopic composition of N2O from excreta of beef steers fed ‘AU Grazer’ sericea lespedeza hay [SL; Lespedeza cuneata (Dum. Cours.) G. Don]. Fifteen Brahman × Angus crossbred steers were fed one of three experimental diets: 0, 50, or 100% inclusion of SL into ‘Tifton-85’ bermudagrass hay (Cynodon spp.). Gas sampling occurred on days 0, 1, 3, 5, 7, 14, 18, 25, and 32 after excreta application to static chambers for two experimental periods. Effect of the day after feces application was found for all greenhouse gases (GHG, P < 0.0001), while interactions between day × inclusion of SL in urine (P < 0.0001) were observed, with 100SL presenting lesser emissions in the initial days. Peaks of emission of all GHG occurred in the initial days (P < 0.0001), with days 3 and 5 being most depleted in 15N-N2O in feces, and days 3, 5, and 7, in urine. Feeding SL to beef steers was effective in mitigating the emission of GHG from the excreta, but further research is warranted to investigate the mechanisms behind the reductions.