|Rotz, Clarence - Al|
Submitted to: Animal
Publication Type: Review Article
Publication Acceptance Date: 4/15/2013
Publication Date: 8/2/2013
Citation: Gerber, P.J., Hristov, A.N., Henderson, B., Makkar, H., Oh, J., Lee, C., Meinen, R., Montes, F., Ott, T., Firkins, J., Rotz, C.A., Dell, C.J., Adesogan, A., Yang, W.Z., Tricarico, J., Kebreab, E., Waghorn, G., Dijkstra, J., Oosting, S. 2013. Technical options for the mitigation of direct methane and nitrous oxide emissions from livestock – a review. Animal. 7 s2 p. 220-234. Interpretive Summary:
Technical Abstract: While livestock production accounts for a sizeable share of global greenhouse gas emissions, numerous technical options have been identified to mitigate these emissions. In this review, a subset of these options which have proven to be effective are discussed. These include measures to reduce methane emissions from enteric fermentation by ruminants, the largest single emission source from the global livestock sector, and for reducing methane and nitrous oxide emissions from manure. A unique feature of this review is the high level of attention given to interactions between mitigation options and productivity. Among the feed supplement options for lowering enteric emissions, dietary lipids, nitrates and ionophores are earmarked as the most highly recommended. Whereas forage quality, feed processing and precision feeding have the best prospects among the various available feed and feed management measures. With regard to manure, dietary measures which lower the amount of nitrogen excreted (e.g. better matching of dietary protein to animal needs), shift of nitrogen excretion from urine to faeces (e.g. tannin inclusion at low levels), and lower the amount of fermentable organic matter excreted, are recommended. Among the many end-of-pipe measures available for manure management, approaches that capture and/or process methane emissions during storage (e.g. anaerobic digestion, biofiltration, composting) as well as subsurface injection of manure are among the most encouraging options flagged in this section of the review. The importance of a multiple gas perspective is critical when assessing mitigation potentials, because most of the options reviewed show strong interactions among sources of greenhouse gas emissions. The paper reviews current knowledge on potential pollution swapping, whereby the reduction of one greenhouse gas or emission source leads to unintended increases in another.