03249naa a2200301 a 450000100080000000500110000800800410001902400410006010000200010124501500012126000090027150001470028052020900042765300220251765300210253965300280256065300230258865300140261165300200262570000170264570000230266270000170268570000170270270000180271970000190273770000290275677301620278510613282021-04-13       2020    bl uuuu     u00u1 u    #d7 a10.1016/j.scitotenv.2020.1420292DOI1 aZUBIETA, Á.S.;  aDoes grazing management provide opportunities to mitigate methane emissions by ruminants in pastoral ecosystems? (Review).h[electronic resource]  c2020  aArticle history: Received 18 May 2020 // Received in revised form 26 August 2020 // Accepted 26 August 2020 // Available online 31 August 2020  aAgriculture, and livestock production in particular, is criticized for being a contributor to global environmental change, including emissions of greenhouse gases (GHG). Methane (CH4) from grazing ruminants accounts for most of livestock's carbon footprint because a large share of them are reared under suboptimal grazing conditions, usually resulting in both low herbage intake and animal performance. Consequently, the CH4 quota attributed to animal maintenance is spread across fewor no animal outputs, increasing the CH4 intensity [g CH4/kg live weight (LW) gain or g CH4/kg milk yield]. In this review, the generalized idea relating tropical pastureswith low quality and intrinsically higher CH4 intensity is challenged by showing evidence that emissions from animals grazing tropical pastures can equal those of temperate grasses. We demonstrate the medium-to-high mitigation potential of some grazing management strategies to mitigate CH4 emissions from grazing ruminants and stress the predominant role that sward canopy structure (e.g., height) has over animal behavioral responses (e.g., intake rate), daily forage intake and resulting CH4 emissions. From this ecological perspective, we identify a grazing management concept aiming to offer the best sward structure that allows animals to optimize their daily herbage intake, creating opportunities to reduce CH4 intensity.We showthe trade-off between animal performance and CH4 intensity, stressing that mitigation is substantial when grazing management is conducted under light-to-moderate intensities and optimize herbage intake and animal performance. Weconclude that optimizing LW gain of grazing sheep and cattle to a threshold of 0.14 and 0.7 kg/day, respectively, would dramatically reduce CH4 intensity to approximately 0.2 kg CH4/kg LW gain, as observed in some intensive feeding systems. This could represent a mitigation potential of around 55% for livestock commodities in pasture-based systems. Our results offer newinsights to the debate concerning mitigation of environmental impacts of pastoral ecosystems.  aANIMAL PRODUCTION  aCARBON FOOTPRINT  aCLIMATE SMART LIVESTOCK  aEMISSION INTENSITY  aGRASSLAND  aSWARD STRUCTURE1 aSAVIAN, J.V.1 aDE SOUZA FILHO, W.1 aWALLAU, M.O.1 aGÓMEZ, A.M.1 aBINDELLE, J.;1 aBONNET, O.J.F.1 aDE FACCIO CARVALHO, P.C.  tScience of the Total Environment, 1 February 2021, Volume 754, Article number 142029. DOI: https://doi-org.proxy.timbo.org.uy/10.1016/j.scitotenv.2020.142029