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Journal of Animal Science Abstract - Invited Reviews

SPECIAL TOPICS — Mitigation of methane and nitrous oxide emissions from animal operations: I. A review of enteric methane mitigation options1


This article in JAS

  1. Vol. 91 No. 11, p. 5045-5069
    unlockOPEN ACCESS
    Received: Apr 12, 2013
    Accepted: Aug 18, 2013
    Published: November 24, 2014

    2 Corresponding author(s):

  1. A. N. Hristov 2,
  2. J. Oh*,
  3. J. L. Firkins,
  4. J. Dijkstra,
  5. E. Kebreab§,
  6. G. Waghorn#,
  7. H. P. S. Makkar,
  8. A. T. Adesogan,
  9. W. Yang**,
  10. C. Lee*,
  11. P. J. Gerber,
  12. B. Henderson and
  13. J. M. Tricarico††
  1. Department of Animal Science, The Pennsylvania State University, University Park 16802
    The Ohio State University, Columbus 43210
    Wageningen University, 6700 AH Wageningen, The Netherlands
    University of California–Davis, Davis 95616
    DairyNZ, Hamilton 3240, New Zealand
    Agriculture and Consumer Protection Department, Food and Agriculture Organization of the United Nations, 00153 Rome, Italy
    Department of Animal Sciences, University of Florida, Gainesville 32608
    Agriculture and Agri-Food Canada, Lethbridge AB T1J 4B1, Canada
    Innovation Center for U.S. Dairy, Rosemont, IL 60018


The goal of this review was to analyze published data related to mitigation of enteric methane (CH4) emissions from ruminant animals to document the most effective and sustainable strategies. Increasing forage digestibility and digestible forage intake was one of the major recommended CH4 mitigation practices. Although responses vary, CH4 emissions can be reduced when corn silage replaces grass silage in the diet. Feeding legume silages could also lower CH4 emissions compared to grass silage due to their lower fiber concentration. Dietary lipids can be effective in reducing CH4 emissions, but their applicability will depend on effects on feed intake, fiber digestibility, production, and milk composition. Inclusion of concentrate feeds in the diet of ruminants will likely decrease CH4 emission intensity (Ei; CH4 per unit animal product), particularly when inclusion is above 40% of dietary dry matter and rumen function is not impaired. Supplementation of diets containing medium to poor quality forages with small amounts of concentrate feed will typically decrease CH4 Ei. Nitrates show promise as CH4 mitigation agents, but more studies are needed to fully understand their impact on whole-farm greenhouse gas emissions, animal productivity, and animal health. Through their effect on feed efficiency and rumen stoichiometry, ionophores are likely to have a moderate CH4 mitigating effect in ruminants fed high-grain or mixed grain–forage diets. Tannins may also reduce CH4 emissions although in some situations intake and milk production may be compromised. Some direct-fed microbials, such as yeast-based products, might have a moderate CH4–mitigating effect through increasing animal productivity and feed efficiency, but the effect is likely to be inconsistent. Vaccines against rumen archaea may offer mitigation opportunities in the future although the extent of CH4 reduction is likely to be small and adaptation by ruminal microbes and persistence of the effect is unknown. Overall, improving forage quality and the overall efficiency of dietary nutrient use is an effective way of decreasing CH4 Ei. Several feed supplements have a potential to reduce CH4 emission from ruminants although their long-term effect has not been well established and some are toxic or may not be economically feasible.

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Copyright © 2013. American Society of Animal Science