Meta-analysis of lipid- and starch-based dietary interventions to mitigate enteric methane emissions, fecal organic matter, fecal and urinary nitrogen excretion in dairy cows

Akinropo, T., Benaouda, M., Bannink, A., Arndt, C., Bayat, A., Crompton, L., Dijkstra, J., Hellwing, A., Hristov, A., Huhtanent, P., Jonker, A., Kebreab, E., de Klein, C., Kreuzer, M., Kuhla, B., Lanigan, G., Lund, P., McCelland, S., McGee, M., Moate, P., Munoz, C., Oh, J., Peiren, N., Ramin, M., Reynolds, C. ORCID: https://orcid.org/0000-0002-4152-1190, Schwarm, A., van Gastelen, S., van Lingen, H., Weisberg, M., Yáñez-Ruiz, D., Yu, Z., Sauvant, D., Blondiaux, P., Martin, C. and Eugène, M. (2026) Meta-analysis of lipid- and starch-based dietary interventions to mitigate enteric methane emissions, fecal organic matter, fecal and urinary nitrogen excretion in dairy cows. Journal of Dairy Science. ISSN 0022-0302 (In Press)

Abstract/Summary

Dietary supplementation of dairy cow diets with lipid or starch are known strategies to mitigate enteric methane (CH4) emission. However, the consequences of these nutritional strategies on N and OM excretion in feces and urine, as well as other environmentally relevant forms of emissions, need to be jointly evaluated. The present meta-analysis assessed the impact of dietary lipid supplementation (LS) and increased dietary starch content (IS) on absolute production or excretion (g/d), yield (g/kg DMI, and g/g N intake for N excretion parameters) and intensity (g/kg ECM) of CH4, fecal OM (FOM), fecal N (FN), urinary N (UN), and total N (TN excretion). Records of treatment means were obtained from 172 experiments (678 treatment means) conducted with dairy cows. Univariate and multivariate statistical analyses evaluated the effect of LS or IS (analyzed separately) to examine how variations in dietary ether extract (EE) or starch (STA) contents relate to CH4 emissions, and FOM, TN, FN, and UN excretions, with or without using additional explanatory parameters obtained from diet composition and animal characteristics. Simple univariate models indicated that with LS experiments, an increase in dietary EE content of 1.0 g/kg DM reduced CH4 emission, yield, and intensity by 2.03 g/d, 0.077 g/kg DMI, and 0.082 g/kg ECM; dietary EE content alone did not influence FOM or N, yield or intensity, except for a decrease in FN excretion. With IS experiments, simple univariate models revealed that an increase in STA content of 1.0 g/kg DM reduced CH4 yield by 0.0085 g/kg DMI and CH4 intensity by 0.013 g/kg ECM. An increase in STA content increased FOM excretion and decreased TN, FN yield and FN intensity. In complex univariate models, DMI and CP content (g/kg DM) exhibited positive relationships relationship with N excretions (g/d) in both strategies. In the multivariate models, either EE or STA contents had no tradeoffs or synergies in production (g/d) and intensity (g/kg ECM). However, either EE and STA content decreased CH4 yield but increased FOM yield in lipid-based diets. Other dietary characteristics were identified as drivers of the relationships between pollutants for production (g/d) and yield (g/kg DM). A decrease in DMI leads to a decrease in both CH4 and TN production, as well as a decrease in both CH4 and FOM production (2Y) for both strategies. Similarly, decreased feeding level and NDF content reduced CH4 and FN production (g/d) in lipid-based diets (3Y). Decreased DMI decreased CH4, FN and UN production, and CH4 TN and FOM production (g/d) in starch-starch based diets. For yield (g/kg DM), decreased NDF content decreased CH4 and FOM yields in LS experiments, while PCO induced tradeoffs between CH4 and FN yields; and CP content induced trade between TN and FOM yield in starch-based diets. In conclusion, the results of this meta- analysis indicated that CH4 production, FOM and N excretions can be lowered simultaneously if diets are designed to achieve dietary balance considering nutrients with direct and indirect effects such as NDF, CP with reduced DMI.

Item Type	Article
URI	https://centaur.reading.ac.uk/id/eprint/128934
Refereed	Yes
Divisions	Life Sciences > School of Agriculture, Policy and Development > Department of Animal Sciences Life Sciences > School of Agriculture, Policy and Development > Centre for Dairy Research (CEDAR)
Publisher	Elsevier
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