Free Standard AU & NZ Shipping For All Book Orders Over $80!
Register      Login
Animal Production Science Animal Production Science Society
Food, fibre and pharmaceuticals from animals
RESEARCH ARTICLE (Open Access)

Feed additives as a strategic approach to reduce enteric methane production in cattle: modes of action, effectiveness and safety

M. Honan A , X. Feng A , J.M. Tricarico https://orcid.org/0000-0002-2101-1564 B and E. Kebreab https://orcid.org/0000-0002-0833-1352 A C
+ Author Affiliations
- Author Affiliations

A Department of Animal Science, University of California, Davis, 2111 Meyer Hall, One Shields Avenue, Davis, CA, 95618, USA.

B Innovation Center for US Dairy, 10255 West Higgins Road, Suite 900, Rosemont, IL 60018, USA.

C Corresponding author. Email: ekebreab@ucdavis.edu

Animal Production Science - https://doi.org/10.1071/AN20295
Submitted: 22 May 2020  Accepted: 23 November 2020   Published online: 2 February 2021

Journal compilation © CSIRO 2021 Open Access CC BY-NC-ND

Abstract

Increasing consumer concern in greenhouse-gas (GHG) contributions from cattle is pushing the livestock industry to continue to improve their sustainability goals. As populations increase, particularly in low-income countries, the demand for animal-sourced foods will place further pressure to reduce emission intensity. Enteric methane (CH4) production contributes to most of the GHG from livestock; therefore, it is key to mitigating such emissions. Feed additives have primarily been used to increase animal productivity, but advances in understanding the rumen has resulted in their development to mitigate CH4 emissions. The present study reviewed some of the main feed additives with a potential to reduce enteric CH4 emissions, focusing on in vivo studies. Feed additives work by either inhibiting methanogenesis or modifying the rumen environment, such that CH4 production (g/day) is reduced. Feed additives that inhibit methanogenesis or compete with substrate for methanogens include 3-nitroxypropanol (3NOP), nitrates, and halogenated compounds containing organisms such as macroalgae. Although 3NOP and macroalgae affect methyl–coenzyme M reductase enzyme that is necessary in CH4 biosynthesis, the former is more specific to methanogens. In contrast, nitrates reduce CH4 emissions by competing with methanogens for hydrogen. However, nitrite could accumulate in blood and be toxic to ruminants. Rumen modifiers do not act directly on methanogens but rather on the conditions that promote methanogenesis. These feed additives include lipids, plant secondary compounds and essential oils. The efficacy of lipids has been studied extensively, and although supplementation with medium-chain and polyunsaturated fatty acids has shown substantial reduction in enteric CH4 production, the results have been variable. Similarly, secondary plant compounds and essential oils have shown inconsistent results, ranging from substantial reduction to modest increase in enteric CH4 emissions. Due to continued interest in this area, research is expected to accelerate in developing feed additives that can provide options in mitigating enteric CH4 emissions.

Keywords: greenhouse gases, methanogens, rumen function, ruminants.


References

Animut G, Puchala R, Goetsch AL, Patra AK, Sahlu T, Varel VH, Wells J (2008) Methane emission by goats consuming diets with different levels of condensed tannins from lespedeza. Animal Feed Science and Technology 144, 212–227.
Methane emission by goats consuming diets with different levels of condensed tannins from lespedeza.Crossref | GoogleScholarGoogle Scholar |

Appuhamy JRN, Strathe AB, Jayasundara S, Wagner-Riddle C, Dijkstra J, France J, Kebreab E (2013) Anti-methanogenic effects of monensin in dairy and beef cattle: a meta-analysis. Journal of Dairy Science 96, 5161–5173.
Anti-methanogenic effects of monensin in dairy and beef cattle: a meta-analysis.Crossref | GoogleScholarGoogle Scholar |

Asanuma N, Yokoyama S, Hino T (2015) Effects of nitrate addition to a diet on fermentation and microbial populations in the rumen of goats, with special reference to Selenomonas ruminantium having the ability to reduce nitrate and nitrite. Animal Science Journal 86, 378–384.
Effects of nitrate addition to a diet on fermentation and microbial populations in the rumen of goats, with special reference to Selenomonas ruminantium having the ability to reduce nitrate and nitrite.Crossref | GoogleScholarGoogle Scholar | 25439583PubMed |

Banerjee R, Ragsdale SW (2003) The many faces of vitamin B12: catalysis by cobalamin-dependent enzymes. Annual Review of Biochemistry 72, 209–247.
The many faces of vitamin B12: catalysis by cobalamin-dependent enzymes.Crossref | GoogleScholarGoogle Scholar | 14527323PubMed |

Bauchop T, Mountfort DO (1981) Cellulose fermentation by a rumen anaerobic fungus in both the absence and the presence of rumen methanogens. Applied and Environmental Microbiology 42, 1103–1110.
Cellulose fermentation by a rumen anaerobic fungus in both the absence and the presence of rumen methanogens.Crossref | GoogleScholarGoogle Scholar | 16345902PubMed |

Bayat AR, Kairenius P, Stefański T, Leskinen H, Comtet-Marre S, Forano E, Chaucheyras-Durand F, Shingfield KJ (2015) Effect of camelina oil or live yeasts (Saccharomyces cerevisiae) on ruminal methane production, rumen fermentation, and milk fatty acid composition in lactating cows fed grass silage diets. Journal of Dairy Science 98, 3166–3181.
Effect of camelina oil or live yeasts (Saccharomyces cerevisiae) on ruminal methane production, rumen fermentation, and milk fatty acid composition in lactating cows fed grass silage diets.Crossref | GoogleScholarGoogle Scholar | 25726099PubMed |

Beauchemin KA, Kreuzer M, O’mara F, McAllister TA (2008) Nutritional management for enteric methane abatement: a review Australian Journal of Experimental Agriculture 48, 21–27.
Nutritional management for enteric methane abatement: a reviewCrossref | GoogleScholarGoogle Scholar |

Beauchemin KA, McAllister TA, McGinn SM (2009a) Dietary mitigation of enteric methane from cattle. Perspectives in Agriculture, Veterinary Science, Nutrition and Natural Resources 4, 1–18.
Dietary mitigation of enteric methane from cattle.Crossref | GoogleScholarGoogle Scholar |

Beauchemin KA, McGinn SM, Benchaar C, Holtshausen L (2009b) Crushed sunflower, flax, or canola seeds in lactating dairy cow diets: effects on methane production, rumen fermentation, and milk production. Journal of Dairy Science 92, 2118–2127.
Crushed sunflower, flax, or canola seeds in lactating dairy cow diets: effects on methane production, rumen fermentation, and milk production.Crossref | GoogleScholarGoogle Scholar | 19389969PubMed |

Benchaar C (2016) Diet supplementation with cinnamon oil, cinnamaldehyde, or monensin does not reduce enteric methane production of dairy cows. Animal 10, 418–425.
Diet supplementation with cinnamon oil, cinnamaldehyde, or monensin does not reduce enteric methane production of dairy cows.Crossref | GoogleScholarGoogle Scholar | 26888487PubMed |

Benchaar C (2020) Feeding oregano oil and its main component carvacrol does not affect ruminal fermentation, nutrient utilization, methane emissions, milk production, or milk fatty acid composition of dairy cows. Journal of Dairy Science 103, 1516–1527.
Feeding oregano oil and its main component carvacrol does not affect ruminal fermentation, nutrient utilization, methane emissions, milk production, or milk fatty acid composition of dairy cows.Crossref | GoogleScholarGoogle Scholar | 31759586PubMed |

Benchaar C, Greathead H (2011) Essential oils and opportunities to mitigate enteric methane emissions from ruminants. Animal Feed Science and Technology 166, 338–355.
Essential oils and opportunities to mitigate enteric methane emissions from ruminants.Crossref | GoogleScholarGoogle Scholar |

Benchaar C, Calsamiglia S, Chaves AV, Fraser GR, Colombatto D, McAllister TA, Beauchemin KA (2008) A review of plant-derived essential oils in ruminant nutrition and production. Animal Feed Science and Technology 145, 209–228.

Benchaar C, Hassanat F, Petit HV (2015) Dose–response to eugenol supplementation to dairy cow diets: methane production, N excretion, ruminal fermentation, nutrient digestibility, milk production, and milk fatty acid profile. Animal Feed Science and Technology 209, 51–59.
Dose–response to eugenol supplementation to dairy cow diets: methane production, N excretion, ruminal fermentation, nutrient digestibility, milk production, and milk fatty acid profile.Crossref | GoogleScholarGoogle Scholar |

Béra-Maillet C, Ribot Y, Forano E (2004) Fiber-degrading systems of different strains of the genus Fibrobacter. Applied and Environmental Microbiology 70, 2172–2179.
Fiber-degrading systems of different strains of the genus Fibrobacter.Crossref | GoogleScholarGoogle Scholar | 15066810PubMed |

Bergman EN (1990) Energy contributions of volatile fatty acids from the gastrointestinal tract in various species. Physiological Reviews 70, 567–590.
Energy contributions of volatile fatty acids from the gastrointestinal tract in various species.Crossref | GoogleScholarGoogle Scholar | 2181501PubMed |

Bruning-Fann CS, Kaneene JB (1993) The effects of nitrate, nitrite and N-nitroso compounds on human health: a review. Veterinary and Human Toxicology 35, 521–538.

Busquet M, Calsamiglia S, Ferret A, Carro MD, Kamel C (2005a) Effect of garlic oil and four of its compounds on rumen microbial fermentation. Journal of Dairy Science 88, 4393–4404.
Effect of garlic oil and four of its compounds on rumen microbial fermentation.Crossref | GoogleScholarGoogle Scholar | 16291631PubMed |

Busquet M, Calsamiglia S, Ferret A, Cardozo PW, Kamel C (2005b) Effects of cinnamaldehyde and garlic oil on rumen microbial fermentation in a dual flow continuous culture. Journal of Dairy Science 88, 2508–2516.
Effects of cinnamaldehyde and garlic oil on rumen microbial fermentation in a dual flow continuous culture.Crossref | GoogleScholarGoogle Scholar | 15956313PubMed |

Caetano M, Wilkes MJ, Pitchford WS, Lee SJ, Hynd PI (2019) Effect of ensiled crimped grape marc on energy intake, performance and gas emissions of beef cattle. Animal Feed Science and Technology 247, 166–172.
Effect of ensiled crimped grape marc on energy intake, performance and gas emissions of beef cattle.Crossref | GoogleScholarGoogle Scholar |

Castro-Montoya J, Peiren N, Cone JW, Zweifel B, Fievez V, De Campeneere S (2015) In vivo and in vitro effects of a blend of essential oils on rumen methane mitigation. Livestock Science 180, 134–142.
In vivo and in vitro effects of a blend of essential oils on rumen methane mitigation.Crossref | GoogleScholarGoogle Scholar |

Chalupa W (1977) Manipulating rumen fermentation. Journal of Animal Science 45, 585–599.
Manipulating rumen fermentation.Crossref | GoogleScholarGoogle Scholar |

Chen D, Chen X, Tu Y, Wang B, Lou C, Ma T, Diao Q (2015) Effects of mulberry leaf flavonoid and resveratrol on methane emission and nutrient digestion in sheep. Animal Nutrition 1, 362–367.
Effects of mulberry leaf flavonoid and resveratrol on methane emission and nutrient digestion in sheep.Crossref | GoogleScholarGoogle Scholar | 29767046PubMed |

Chen J, Harstad OM, McAllister T, Dörsch P, Holo H (2020) Propionic acid bacteria enhance ruminal feed degradation and reduce methane production in vitro. Acta Agriculturæ Scandinavica. Section A, Animal Science 69, 169–175.
Propionic acid bacteria enhance ruminal feed degradation and reduce methane production in vitro.Crossref | GoogleScholarGoogle Scholar |

Cottle DJ, Nolan JV, Wiedemann SG (2011) Ruminant enteric methane mitigation: a review. Animal Production Science 51, 491–514.
Ruminant enteric methane mitigation: a review.Crossref | GoogleScholarGoogle Scholar |

Darabighane B, Salem AZM, Aghjehgheshlagh FM, Mahdavi A, Zarei A, Elghandour MMMY, López S (2019) Environmental efficiency of Saccharomyces cerevisiae on methane production in dairy and beef cattle via a meta-analysis. Environmental Science and Pollution Research International 26, 3651–3658.
Environmental efficiency of Saccharomyces cerevisiae on methane production in dairy and beef cattle via a meta-analysis.Crossref | GoogleScholarGoogle Scholar | 30535735PubMed |

Dijkstra J, Bannink A, France J, Kebreab E, van Gastelen S (2018) Antimethanogenic effects of 3-nitrooxypropanol depend on supplementation dose, dietary fiber content, and cattle type. Journal of Dairy Science 101, 9041–9047.
Antimethanogenic effects of 3-nitrooxypropanol depend on supplementation dose, dietary fiber content, and cattle type.Crossref | GoogleScholarGoogle Scholar | 30055923PubMed |

Doce RR, Belenguer A, Toral PG, Hervás G, Frutos P (2013) Effect of the administration of young leaves of Quercus pyrenaica on rumen fermentation in relation to oak tannin toxicosis in cattle. Journal of Animal Physiology and Animal Nutrition 97, 48–57.
Effect of the administration of young leaves of Quercus pyrenaica on rumen fermentation in relation to oak tannin toxicosis in cattle.Crossref | GoogleScholarGoogle Scholar | 21992033PubMed |

Dong Y, Bae HD, McAllister TA, Mathison GW, Cheng KJ (1997) Lipid-induced depression of methane production and digestibility in the artificial rumen system (RUSITEC). Canadian Journal of Animal Science 77, 269–278.
Lipid-induced depression of methane production and digestibility in the artificial rumen system (RUSITEC).Crossref | GoogleScholarGoogle Scholar |

Doyle N, Mbandlwa P, Kelly WJ, Attwood G, Li Y, Ross RP, Stanton C, Leahy S (2019) Use of lactic acid bacteria to reduce methane production in ruminants, a critical review. Frontiers in Microbiology 10, 2207
Use of lactic acid bacteria to reduce methane production in ruminants, a critical review.Crossref | GoogleScholarGoogle Scholar | 31632365PubMed |

Duin EC, Wagner T, Shima S, Prakash D, Cronin B, Yáñez-Ruiz DR, Duval S, Rümbeli R, Stemmler RT, Thauer RK, Kindermann M (2016) Mode of action uncovered for the specific reduction of methane emissions from ruminants by the small molecule 3-nitrooxypropanol. Proceedings of the National Academy of Sciences of the United States of America 113, 6172–6177.
Mode of action uncovered for the specific reduction of methane emissions from ruminants by the small molecule 3-nitrooxypropanol.Crossref | GoogleScholarGoogle Scholar | 27140643PubMed |

Duthie CA, Troy SM, Hyslop JJ, Ross DW, Roehe R, Rooke JA (2018) The effect of dietary addition of nitrate or increase in lipid concentrations, alone or in combination, on performance and methane emissions of beef cattle. Animal 12, 280–287.
The effect of dietary addition of nitrate or increase in lipid concentrations, alone or in combination, on performance and methane emissions of beef cattle.Crossref | GoogleScholarGoogle Scholar | 28701247PubMed |

Edris AE (2007) Pharmaceutical and therapeutic potentials of essential oils and their individual volatile constituents: a review. Phytotherapy Research: An International Journal Devoted to Pharmacological and Toxicological Evaluation of Natural Product Derivatives 21, 308–323.
Pharmaceutical and therapeutic potentials of essential oils and their individual volatile constituents: a review.Crossref | GoogleScholarGoogle Scholar |

Eger M, Graz M, Riede S, Breves G (2018) Application of MootralTM reduces methane production by altering the archaea community in the rumen simulation technique. Frontiers in Microbiology 9, 2094
Application of MootralTM reduces methane production by altering the archaea community in the rumen simulation technique.Crossref | GoogleScholarGoogle Scholar | 30233557PubMed |

Elcoso G, Zweifel B, Bach A (2019) Effects of a blend of essential oils on milk yield and feed efficiency of lactating dairy cows. Applied Animal Science 35, 304–311.
Effects of a blend of essential oils on milk yield and feed efficiency of lactating dairy cows.Crossref | GoogleScholarGoogle Scholar |

Ellis JL, Dijkstra J, Kebreab E, Bannink A, Odongo NE, McBride BW, France J (2008) Aspects of rumen microbiology central to mechanistic modelling of methane production in cattle. The Journal of Agricultural Science 146, 213–233.
Aspects of rumen microbiology central to mechanistic modelling of methane production in cattle.Crossref | GoogleScholarGoogle Scholar |

Eugène M, Massé D, Chiquette J, Benchaar C (2008) Meta-analysis on the effects of lipid supplementation on methane production in lactating dairy cows. Canadian Journal of Animal Science 88, 331–337.
Meta-analysis on the effects of lipid supplementation on methane production in lactating dairy cows.Crossref | GoogleScholarGoogle Scholar |

Feng Y, Xu Y, Yu Y, Xie Z, Lin X (2012) Mechanisms of biochar decreasing methane emission from Chinese paddy soils. Soil Biology & Biochemistry 46, 80–88.
Mechanisms of biochar decreasing methane emission from Chinese paddy soils.Crossref | GoogleScholarGoogle Scholar |

Feng XY, Dijkstra J, Bannink A, van Gastelen S, France J, Kebreab E (2020) Anti-methanogenic effects of nitrate supplementation in cattle: a meta-analysis. Journal of Dairy Science 103, 11375–11385.
Anti-methanogenic effects of nitrate supplementation in cattle: a meta-analysis.Crossref | GoogleScholarGoogle Scholar | 32981733PubMed |

Figueiredo AC, Barroso JG, Pedro LG, Scheffer JJ (2008) Factors affecting secondary metabolite production in plants: volatile components and essential oils. Flavour and Fragrance Journal 23, 213–226.
Factors affecting secondary metabolite production in plants: volatile components and essential oils.Crossref | GoogleScholarGoogle Scholar |

Gagen EJ, Wang J, Padmanabha J, Liu J, de Carvalho IPC, Liu J, Webb RI, Al Jassim R, Morrison M, Denman SE, McSweeney CS (2014) Investigation of a new acetogen isolated from an enrichment of the tammar wallaby forestomach. BMC Microbiology 14, 314
Investigation of a new acetogen isolated from an enrichment of the tammar wallaby forestomach.Crossref | GoogleScholarGoogle Scholar | 25495654PubMed |

Gerber PJ, Steinfeld H, Henderson B, Mottet A, Opio C, Dijkman J, Falcucci A, Tempio G (2013) ‘Tackling climate change through livestock: a global assessment of emissions and mitigation opportunities.’ (Food and Agriculture Organization of the United Nations (FAO): Rome, Italy)

Goel G, Makkar HP, Becker K (2009) Inhibition of methanogens by bromochloromethane: effects on microbial communities and rumen fermentation using batch and continuous fermentations. British Journal of Nutrition 101, 1484–1492.
Inhibition of methanogens by bromochloromethane: effects on microbial communities and rumen fermentation using batch and continuous fermentations.Crossref | GoogleScholarGoogle Scholar |

Granja-Salcedo YT, Fernandes RM, Araujo RCD, Kishi LT, Berchielli TT, Resende FDD, Berndt A, Siqueira GR (2019) Long-term encapsulated nitrate supplementation modulates rumen microbial diversity and rumen fermentation to reduce methane emission in grazing steers. Frontiers in Microbiology 10, 614
Long-term encapsulated nitrate supplementation modulates rumen microbial diversity and rumen fermentation to reduce methane emission in grazing steers.Crossref | GoogleScholarGoogle Scholar | 30984141PubMed |

Gribble GW (2004) Amazing organohalogens: although best known as synthetic toxicants, thousands of halogen compounds are, in fact, part of our natural environment. American Scientist 92, 342–349.
Amazing organohalogens: although best known as synthetic toxicants, thousands of halogen compounds are, in fact, part of our natural environment.Crossref | GoogleScholarGoogle Scholar |

Guan H, Wittenberg KM, Ominski KH, Krause DO (2006) Efficacy of ionophores in cattle diets for mitigation of enteric methane. Journal of Animal Science 84, 1896–1906.
Efficacy of ionophores in cattle diets for mitigation of enteric methane.Crossref | GoogleScholarGoogle Scholar | 16775074PubMed |

Guyader J, Eugène M, Meunier B, Doreau M, Morgavi DP, Silberberg M, Rochette Y, Gerard C, Loncke C, Martin C (2015a) Additive methane-mitigating effect between linseed oil and nitrate fed to cattle. Journal of Animal Science 93, 3564–3577.
Additive methane-mitigating effect between linseed oil and nitrate fed to cattle.Crossref | GoogleScholarGoogle Scholar | 26440025PubMed |

Haisan J, Sun Y, Guan LL, Beauchemin KA, Iwaasa A, Duval S, Barreda DR, Oba M (2014) The effects of feeding 3-nitrooxypropanol on methane emissions and productivity of Holstein cows in mid lactation. Journal of Dairy Science 97, 3110–3119.
The effects of feeding 3-nitrooxypropanol on methane emissions and productivity of Holstein cows in mid lactation.Crossref | GoogleScholarGoogle Scholar | 24630651PubMed |

Hart KJ, Jones HG, Waddams KE, Worgan HJ, Zweifel B, Newbold CJ (2019) An essential oil blend decreases methane emissions and increases milk yield in dairy cows. Open Journal of Animal Sciences 9, 259
An essential oil blend decreases methane emissions and increases milk yield in dairy cows.Crossref | GoogleScholarGoogle Scholar |

Helander IM, Alakomi HL, Latva-Kala K, Mattila-Sandholm T, Pol I, Smid EJ, Gorris LG, von Wright A (1998) Characterization of the action of selected essential oil components on Gram-negative bacteria. Journal of Agricultural and Food Chemistry 46, 3590–3595.
Characterization of the action of selected essential oil components on Gram-negative bacteria.Crossref | GoogleScholarGoogle Scholar |

Hess HD, Monsalve LM, Lascano CE, Carulla JE, Diaz TE, Kreuzer M (2003) Supplementation of a tropical grass diet with forage legumes and Sapindus saponaria fruits: effects on in vitro ruminal nitrogen turnover and methanogenesis. Australian Journal of Agricultural Research 54, 703–713.
Supplementation of a tropical grass diet with forage legumes and Sapindus saponaria fruits: effects on in vitro ruminal nitrogen turnover and methanogenesis.Crossref | GoogleScholarGoogle Scholar |

Hollmann M, Powers WJ, Fogiel AC, Liesman JS, Bello NM, Beede DK (2012) Enteric methane emissions and lactational performance of Holstein cows fed different concentrations of coconut oil. Journal of Dairy Science 95, 2602–2615.
Enteric methane emissions and lactational performance of Holstein cows fed different concentrations of coconut oil.Crossref | GoogleScholarGoogle Scholar | 22541489PubMed |

Holtshausen L, Chaves AV, Beauchemin KA, McGinn SM, McAllister TA, Odongo NE, Cheeke PR, Benchaar C (2009) Feeding saponin-containing Yucca schidigera and Quillaja saponaria to decrease enteric methane production in dairy cows. Journal of Dairy Science 92, 2809–2821.
Feeding saponin-containing Yucca schidigera and Quillaja saponaria to decrease enteric methane production in dairy cows.Crossref | GoogleScholarGoogle Scholar | 19448015PubMed |

Hook SE, Wright ADG, McBride BW (2010) Methanogens: methane producers of the rumen and mitigation strategies. Archaea 2010, 945785
Methanogens: methane producers of the rumen and mitigation strategies.Crossref | GoogleScholarGoogle Scholar | 21253540PubMed |

Hristov AN, Vander Pol M, Agle M, Zaman S, Schneider C, Ndegwa P, Vaddella VK, Johnson K, Shingfield KJ, Karnati SKR (2009) Effect of lauric acid and coconut oil on ruminal fermentation, digestion, ammonia losses from manure, and milk fatty acid composition in lactating cows. Journal of Dairy Science 92, 5561–5582.
Effect of lauric acid and coconut oil on ruminal fermentation, digestion, ammonia losses from manure, and milk fatty acid composition in lactating cows.Crossref | GoogleScholarGoogle Scholar | 19841218PubMed |

Hristov AN, Lee C, Cassidy TT, Heyler K, Tekippe JA, Varga GA, Corl B, Brandt RC (2013) Effect of Origanum vulgare L. leaves on rumen fermentation, production, and milk fatty acid composition in lactating dairy cows. Journal of Dairy Science 96, 1189–1202.

Hristov AN, Oh J, Giallongo F, Frederick TW, Harper MT, Weeks HL, Branco AF, Moate PJ, Deighton MH, Williams SRO, Kindermann M (2015) An inhibitor persistently decreased enteric methane emission from dairy cows with no negative effect on milk production. Proceedings of the National Academy of Sciences of the United States of America 112, 10663–10668.
An inhibitor persistently decreased enteric methane emission from dairy cows with no negative effect on milk production.Crossref | GoogleScholarGoogle Scholar | 26229078PubMed |

Hulshof RBA, Berndt A, Gerrits WJJ, Dijkstra J, Van Zijderveld SM, Newbold JR, Perdok HB (2012) Dietary nitrate supplementation reduces methane emission in beef cattle fed sugarcane-based diets. Journal of Animal Science 90, 2317–2323.
Dietary nitrate supplementation reduces methane emission in beef cattle fed sugarcane-based diets.Crossref | GoogleScholarGoogle Scholar |

Hungate RE, Smith W, Bauchop T, Yu I, Rabinowitz JC (1970) Formate as an intermediate in the bovine rumen fermentation. Journal of Bacteriology 102, 389–397.
Formate as an intermediate in the bovine rumen fermentation.Crossref | GoogleScholarGoogle Scholar | 5419259PubMed |

IPCC (2013) ‘Climate change: the physical science basis.’ Working Group I contribution to the IPCC fifth assessment report. (IPCC: Cambridge, UK)

Iwamoto M, Asanuma N, Hino T (2002) Ability of Selenomonas ruminantium, Veillonella parvula, and Wolinella succinogenes to reduce nitrate and nitrite with special reference to the suppression of ruminal methanogenesis. Anaerobe 8, 209–215.
Ability of Selenomonas ruminantium, Veillonella parvula, and Wolinella succinogenes to reduce nitrate and nitrite with special reference to the suppression of ruminal methanogenesis.Crossref | GoogleScholarGoogle Scholar |

Jayanegara A, Leiber F, Kreuzer M (2012) Meta‐analysis of the relationship between dietary tannin level and methane formation in ruminants from in vivo and in vitro experiments. Journal of Animal Physiology and Animal Nutrition 96, 365–375.
Meta‐analysis of the relationship between dietary tannin level and methane formation in ruminants from in vivo and in vitro experiments.Crossref | GoogleScholarGoogle Scholar | 21635574PubMed |

Jayanegara A, Sarwono KA, Kondo M, Matsui H, Ridla M, Laconi EB, Nahrowi (2018) Use of 3-nitrooxypropanol as feed additive for mitigating enteric methane emissions from ruminants: a meta-analysis. Italian Journal of Animal Science 17, 650–656.
Use of 3-nitrooxypropanol as feed additive for mitigating enteric methane emissions from ruminants: a meta-analysis.Crossref | GoogleScholarGoogle Scholar |

Jeyanathan J, Martin C, Eugène M, Ferlay A, Popova M, Morgavi DP (2019) Bacterial direct-fed microbials fail to reduce methane emissions in primiparous lactating dairy cows. Journal of Animal Science and Biotechnology 10, 41
Bacterial direct-fed microbials fail to reduce methane emissions in primiparous lactating dairy cows.Crossref | GoogleScholarGoogle Scholar | 31069075PubMed |

Joblin KN (1999) Ruminal acetogens and their potential to lower ruminant methane emissions. Australian Journal of Agricultural Research 50, 1307–1314.
Ruminal acetogens and their potential to lower ruminant methane emissions.Crossref | GoogleScholarGoogle Scholar |

Joch M, Cermak L, Hakl J, Hucko B, Duskova D, Marounek M (2016) In vitro screening of essential oil active compounds for manipulation of rumen fermentation and methane mitigation. Asian–Australasian Journal of Animal Sciences 29, 952
In vitro screening of essential oil active compounds for manipulation of rumen fermentation and methane mitigation.Crossref | GoogleScholarGoogle Scholar | 26954157PubMed |

Johnson KA, Johnson DE (1995) Methane emissions from cattle. Journal of Animal Science 73, 2483–2492.
Methane emissions from cattle.Crossref | GoogleScholarGoogle Scholar | 8567486PubMed |

Kalus K, Koziel JA, Opaliński S (2019) A review of biochar properties and their utilization in crop agriculture and livestock production. Applied Sciences 9, 3494
A review of biochar properties and their utilization in crop agriculture and livestock production.Crossref | GoogleScholarGoogle Scholar |

Khattab MSA, El-Zaiat HM, El Tawab AA, Matloup OH, Morsy AS, Abdou MM, Ebeid HM, Attia MFA, Sallam SMA (2017) Impact of lemongrass and galangal as feed additives on performance of lactating Barki goats. International Journal of Dairy Science 12, 184–189.
Impact of lemongrass and galangal as feed additives on performance of lactating Barki goats.Crossref | GoogleScholarGoogle Scholar |

Khorrami B, Vakili AR, Mesgaran MD, Klevenhusen F (2015) Thyme and cinnamon essential oils: potential alternatives for monensin as a rumen modifier in beef production systems. Animal Feed Science and Technology 200, 8–16.
Thyme and cinnamon essential oils: potential alternatives for monensin as a rumen modifier in beef production systems.Crossref | GoogleScholarGoogle Scholar |

Kim ET, Le Luo Guan SJL, Lee SM, Lee SS, Lee ID, Lee SK, Lee SS (2015) Effects of flavonoid-rich plant extracts on in vitro ruminal methanogenesis, microbial populations and fermentation characteristics. Asian-Australasian Journal of Animal Sciences 28, 530
Effects of flavonoid-rich plant extracts on in vitro ruminal methanogenesis, microbial populations and fermentation characteristics.Crossref | GoogleScholarGoogle Scholar | 25656200PubMed |

Kim SH, Lee C, Pechtl HA, Hettick JM, Campler MR, Pairis-Garcia MD, Beauchemin KA, Celi P, Duval SM (2019) Effects of 3-nitrooxypropanol on enteric methane production, rumen fermentation, and feeding behavior in beef cattle fed a high-forage or high-grain diet. Journal of Animal Science 97, 2687–2699.
Effects of 3-nitrooxypropanol on enteric methane production, rumen fermentation, and feeding behavior in beef cattle fed a high-forage or high-grain diet.Crossref | GoogleScholarGoogle Scholar | 31115441PubMed |

Kinley RD, Martinez-Fernandez G, Matthews MK, de Nys R, Magnusson M, Tomkins NW (2020) Mitigating the carbon footprint and improving productivity of ruminant livestock agriculture using a red seaweed. Journal of Cleaner Production 259, 120836
Mitigating the carbon footprint and improving productivity of ruminant livestock agriculture using a red seaweed.Crossref | GoogleScholarGoogle Scholar |

Klevenhusen F, Zeitz JO, Duval S, Kreuzer M, Soliva CR (2011) Garlic oil and its principal component diallyl disulfide fail to mitigate methane, but improve digestibility in sheep. Animal Feed Science and Technology 166, 356–363.
Garlic oil and its principal component diallyl disulfide fail to mitigate methane, but improve digestibility in sheep.Crossref | GoogleScholarGoogle Scholar |

Klop G, Dijkstra J, Dieho K, Hendriks WH, Bannink A (2017) Enteric methane production in lactating dairy cows with continuous feeding of essential oils or rotational feeding of essential oils and lauric acid. Journal of Dairy Science 100, 3563–3575.
Enteric methane production in lactating dairy cows with continuous feeding of essential oils or rotational feeding of essential oils and lauric acid.Crossref | GoogleScholarGoogle Scholar | 28237592PubMed |

Knapp JR, Laur GL, Vadas PA, Weiss WP, Tricarico JM (2014) Invited review: enteric methane in dairy cattle production: quantifying the opportunities and impact of reducing emissions. Journal of Dairy Science 97, 3231–3261.
Invited review: enteric methane in dairy cattle production: quantifying the opportunities and impact of reducing emissions.Crossref | GoogleScholarGoogle Scholar | 24746124PubMed |

Knight T, Ronimus RS, Dey D, Tootill C, Naylor G, Evans P, Molano G, Smith A, Tavendale M, Pinares-Patino CS, Clark H (2011) Chloroform decreases rumen methanogenesis and methanogen populations without altering rumen function in cattle. Animal Feed Science and Technology 166, 101–112.
Chloroform decreases rumen methanogenesis and methanogen populations without altering rumen function in cattle.Crossref | GoogleScholarGoogle Scholar |

Kolling GJ, Stivanin SCB, Gabbi AM, Machado FS, Ferreira AL, Campos MM, Tomich TR, Cunha CS, Dill SW, Pereira LGR, Fischer V (2018) Performance and methane emissions in dairy cows fed oregano and green tea extracts as feed additives. Journal of Dairy Science 101, 4221–4234.
Performance and methane emissions in dairy cows fed oregano and green tea extracts as feed additives.Crossref | GoogleScholarGoogle Scholar | 29477520PubMed |

Lambie SC, Kelly WJ, Leahy SC, Li D, Reilly K, McAllister TA, Valle ER, Attwood GT, Altermann E (2015) The complete genome sequence of the rumen methanogen Methanosarcina barkeri CM1. Standards in Genomic Sciences 10, 57
The complete genome sequence of the rumen methanogen Methanosarcina barkeri CM1.Crossref | GoogleScholarGoogle Scholar | 26413197PubMed |

Latham EA, Anderson RC, Pinchak WE, Nisbet DJ (2016) Insights on alterations to the rumen ecosystem by nitrate and nitrocompounds. Frontiers in Microbiology 7, 228
Insights on alterations to the rumen ecosystem by nitrate and nitrocompounds.Crossref | GoogleScholarGoogle Scholar | 26973609PubMed |

Latham EA, Pinchak WE, Trachsel J, Allen HK, Callaway TR, Nisbet DJ, Anderson RC (2019) Paenibacillus 79R4, a potential rumen probiotic to enhance nitrite detoxification and methane mitigation in nitrate-treated ruminants. The Science of the Total Environment 671, 324–328.
Paenibacillus 79R4, a potential rumen probiotic to enhance nitrite detoxification and methane mitigation in nitrate-treated ruminants.Crossref | GoogleScholarGoogle Scholar | 30933788PubMed |

Lee C, Beauchemin KA (2014) A review of feeding supplementary nitrate to ruminant animals: nitrate toxicity, methane emissions, and production performance. Canadian Journal of Animal Science 94, 557–570.
A review of feeding supplementary nitrate to ruminant animals: nitrate toxicity, methane emissions, and production performance.Crossref | GoogleScholarGoogle Scholar |

Lejonklev J, Kidmose U, Jensen S, Petersen MA, Helwing ALF, Mortensen G, Weisbjerg MR, Larsen MK (2016) Effect of oregano and caraway essential oils on the production and flavor of cow milk. Journal of Dairy Science 99, 7898–7903.
Effect of oregano and caraway essential oils on the production and flavor of cow milk.Crossref | GoogleScholarGoogle Scholar | 27522414PubMed |

Leng RA, Preston TR, Inthapanya S (2012)

Li X, Norman HC, Kinley RD, Laurence M, Wilmot M, Bender H, de Nys R, Tomkins N (2018) Asparagopsis taxiformis decreases enteric methane production from sheep. Animal Production Science 58, 681–688.
Asparagopsis taxiformis decreases enteric methane production from sheep.Crossref | GoogleScholarGoogle Scholar |

Lindahl IL, Cook AC, Davis RE, Maclay WD (1954) Preliminary investigations on the role of alfalfa saponin in ruminant bloat. Science 119, 157–158.
Preliminary investigations on the role of alfalfa saponin in ruminant bloat.Crossref | GoogleScholarGoogle Scholar | 13122048PubMed |

Liu Y, Ma T, Chen D, Zhang N, Si B, Deng K, Tu Y, Diao Q (2019) Effects of tea saponin supplementation on nutrient digestibility, methanogenesis, and ruminal microbial flora in Dorper crossbred ewe. Animals (Basel) 9, 29
Effects of tea saponin supplementation on nutrient digestibility, methanogenesis, and ruminal microbial flora in Dorper crossbred ewe.Crossref | GoogleScholarGoogle Scholar |

Lopes JC, de Matos LF, Harper MT, Giallongo F, Oh J, Gruen D, Ono S, Kindermann M, Duval S, Hristov AN (2016) Effect of 3-nitrooxypropanol on methane and hydrogen emissions, methane isotopic signature, and ruminal fermentation in dairy cows. Journal of Dairy Science 99, 5335–5344.
Effect of 3-nitrooxypropanol on methane and hydrogen emissions, methane isotopic signature, and ruminal fermentation in dairy cows.Crossref | GoogleScholarGoogle Scholar | 27085412PubMed |

Machado L, Magnusson M, Paul NA, Kinley R, de Nys R, Tomkins N (2016) Identification of bioactives from the red seaweed Asparagopsis taxiformis that promote antimethanogenic activity in vitro. Journal of Applied Phycology 28, 3117–3126.
Identification of bioactives from the red seaweed Asparagopsis taxiformis that promote antimethanogenic activity in vitro.Crossref | GoogleScholarGoogle Scholar |

Machmüller A, Ossowski DA, Wanner M, Kreuzer M (1998) Potential of various fatty feeds to reduce methane release from rumen fermentation in vitro (Rusitec). Animal Feed Science and Technology 71, 117–130.
Potential of various fatty feeds to reduce methane release from rumen fermentation in vitro (Rusitec).Crossref | GoogleScholarGoogle Scholar |

Malik PK, Bhatta R, Gagen EJ, Sejian V, Soren NM, Prasad CS (2015) Alternate H2 sinks for reducing rumen methanogenesis. In ‘Climate change impact on livestock: adaptation and mitigation’. (Eds V Sejian, J Gaughan, L Baumgard, C Prasad) pp. 303–320. (Springer: New Delhi, India)

Man KY, Chow KL, Man YB, Mo WY, Wong MH (2020) Use of biochar as feed supplements for animal farming. Critical Reviews in Environmental Science and Technology 1–31.
Use of biochar as feed supplements for animal farming.Crossref | GoogleScholarGoogle Scholar |

Martin C, Morgavi DP, Doreau M (2010) Methane mitigation in ruminants: from microbe to the farm scale. Animal 4, 351–365.
Methane mitigation in ruminants: from microbe to the farm scale.Crossref | GoogleScholarGoogle Scholar | 22443940PubMed |

Martinez-Fernandez G, Abecia L, Martín García AI, Ramos Morales E, Hervás G, Molina Alcaide E, Yáñez Ruiz DR (2013) In vitro–in vivo study on the effects of plant compounds on rumen fermentation, microbial abundances and methane emissions in goats. Animal 7, 1925–1934.
In vitro–in vivo study on the effects of plant compounds on rumen fermentation, microbial abundances and methane emissions in goats.Crossref | GoogleScholarGoogle Scholar | 24237672PubMed |

Martinez-Fernandez G, Abecia L, Ramos-Morales E, Martin-García AI, Molina-Alcaide E, Yáñez-Ruiz DR (2014) Effects of propyl propane thiosulfinate on nutrient utilization, ruminal fermentation, microbial population and methane emissions in goats. Animal Feed Science and Technology 191, 16–25.
Effects of propyl propane thiosulfinate on nutrient utilization, ruminal fermentation, microbial population and methane emissions in goats.Crossref | GoogleScholarGoogle Scholar |

Martinez-Fernandez G, Denman SE, Yang C, Cheung J, Mitsumori M, McSweeney CS (2016) Methane inhibition alters the microbial community, hydrogen flow, and fermentation response in the rumen of cattle. Frontiers in Microbiology 7, 1122
Methane inhibition alters the microbial community, hydrogen flow, and fermentation response in the rumen of cattle.Crossref | GoogleScholarGoogle Scholar | 27486452PubMed |

Martinez-Fernandez G, Duval S, Kindermann M, Schirra HJ, Denman SE, McSweeney CS (2018) 3-NOP vs. halogenated compound: methane production, ruminal fermentation and microbial community response in forage fed cattle. Frontiers in Microbiology 9, 1582
3-NOP vs. halogenated compound: methane production, ruminal fermentation and microbial community response in forage fed cattle.Crossref | GoogleScholarGoogle Scholar | 30131771PubMed |

McAllister TA, Cheng KJ, Okine EK, Mathison GW (1996) Dietary, environmental and microbiological aspects of methane production in ruminants. Canadian Journal of Animal Science 76, 231–243.
Dietary, environmental and microbiological aspects of methane production in ruminants.Crossref | GoogleScholarGoogle Scholar |

Meale SJ, Chaves AV, McAllister TA, Iwaasa AD, Yang WZ, Benchaar C (2014) Including essential oils in lactating dairy cow diets: effects on methane emissions1. Animal Production Science 54, 1215–1218.
Including essential oils in lactating dairy cow diets: effects on methane emissions1.Crossref | GoogleScholarGoogle Scholar |

Moate PJ, Williams SRO, Torok VA, Hannah MC, Ribaux BE, Tavendale MH, Eckard RJ, Jacobs JL, Auldist MJ, Wales WJ (2014) Grape marc reduces methane emissions when fed to dairy cows. Journal of Dairy Science 97, 5073–5087.
Grape marc reduces methane emissions when fed to dairy cows.Crossref | GoogleScholarGoogle Scholar | 24952778PubMed |

Morgavi DP, Forano E, Martin C, Newbold CJ (2010) Microbial ecosystem and methanogenesis in ruminants. Animal 4, 1024–1036.
Microbial ecosystem and methanogenesis in ruminants.Crossref | GoogleScholarGoogle Scholar | 22444607PubMed |

Morrissey JP (2009) Biological activity of defence-related plant secondary metabolites. In ‘Plant-derived natural products’. (Eds Osbourne AE, Lanzotti V) pp. 283–299. (Springer: New York, NY, USA)

Mottet A, de Haan C, Falcucci A, Tempio G, Opio C, Gerber P (2017) Livestock: on our plates or eating at our table? A new analysis of the feed/food debate. Global Food Security 14, 1–8.
Livestock: on our plates or eating at our table? A new analysis of the feed/food debate.Crossref | GoogleScholarGoogle Scholar |

Nadathur SR, Wanasundara JPD, Scanlin L (2017) Proteins in the diet: challenges in feeding the global population. In ‘Sustainable protein sources’. (Eds Nadathur SR, Wanasundara JPD, Scanlin L) pp. 1–19. (Academic Press: San Diego, CA, USA)

Nanon A, Suksombat W, Wen ZY (2015) Use of essential oils for manipulation of rumen microbial fermentation using batch culture. Wetchasan Sattawaphaet 45, 167–180.

National Research Council (2001) ‘Nutrient requirements of dairy cattle.’ 7th revised addition 2001. (National Research Council: Washington, DC)

Nogueira RGS, Perna F, Pereira ASC, Cassiano ECO, Carvalho RF, Rodrigues PHM (2020) Methane mitigation and ruminal fermentation changes in cows fed cottonseed and vitamin E. Scientia Agrícola 77, e20180247
Methane mitigation and ruminal fermentation changes in cows fed cottonseed and vitamin E.Crossref | GoogleScholarGoogle Scholar |

Odongo NE, Or-Rashid MM, Kebreab E, France J, McBride BW (2007) Effect of supplementing myristic acid in dairy cow rations on ruminal methanogenesis and fatty acid profile in milk. Journal of Dairy Science 90, 1851–1858.
Effect of supplementing myristic acid in dairy cow rations on ruminal methanogenesis and fatty acid profile in milk.Crossref | GoogleScholarGoogle Scholar | 17369226PubMed |

OECD/FAO (2018) ‘OECD–FAO agricultural outlook 2018–2027.’ (Organization for Economic Cooperation and Development Paris, Food and Agriculture Organization: Rome, Italy)

Olijhoek DW, Hellwing ALF, Brask M, Weisbjerg MR, Højberg O, Larsen MK, Dijkstra J, Erlandsen EJ, Lund P (2016) Effect of dietary nitrate level on enteric methane production, hydrogen emission, rumen fermentation, and nutrient digestibility in dairy cows. Journal of Dairy Science 99, 6191–6205.
Effect of dietary nitrate level on enteric methane production, hydrogen emission, rumen fermentation, and nutrient digestibility in dairy cows.Crossref | GoogleScholarGoogle Scholar | 27236758PubMed |

Olijhoek DW, Hellwing ALF, Grevsen K, Haveman LS, Chowdhury MR, Løvendahl P, Weisbjerg MR, Noel SJ, Højberg O, Wiking L, Lund P (2019) Effect of dried oregano (Origanum vulgare L.) plant material in feed on methane production, rumen fermentation, nutrient digestibility, and milk fatty acid composition in dairy cows. Journal of Dairy Science 102, 9902–9918.
Effect of dried oregano (Origanum vulgare L.) plant material in feed on methane production, rumen fermentation, nutrient digestibility, and milk fatty acid composition in dairy cows.Crossref | GoogleScholarGoogle Scholar | 31495619PubMed |

Opio C, Gerber P, Mottet A, Falcucci A, Tempio G, MacLeod M, Vellinga T, Henderson B, Steinfeld H (2013) ‘Greenhouse gas emissions from ruminant supply chains: a global life cycle assessment.’ (Food and Agriculture Organization of the United Nations: Rome, Italy)

Oskoueian E, Abdullah N, Oskoueian A (2013) Effects of flavonoids on rumen fermentation activity, methane production, and microbial population. BioMed Research International 2013, 349129
Effects of flavonoids on rumen fermentation activity, methane production, and microbial population.Crossref | GoogleScholarGoogle Scholar | 24175289PubMed |

Patra AK (2013) The effect of dietary fats on methane emissions, and its other effects on digestibility, rumen fermentation and lactation performance in cattle: a meta-analysis. Livestock Science 155, 244–254.
The effect of dietary fats on methane emissions, and its other effects on digestibility, rumen fermentation and lactation performance in cattle: a meta-analysis.Crossref | GoogleScholarGoogle Scholar |

Patra AK, Saxena J (2010) A new perspective on the use of plant secondary metabolites to inhibit methanogenesis in the rumen. Phytochemistry 71, 1198–1222.
A new perspective on the use of plant secondary metabolites to inhibit methanogenesis in the rumen.Crossref | GoogleScholarGoogle Scholar | 20570294PubMed |

Patra AK, Kamra DN, Bhar R, Kumar R, Agarwal N (2011) Effect of Terminalia chebula and Allium sativum on in vivo methane emission by sheep. Journal of Animal Physiology and Animal Nutrition 95, 187–191.
Effect of Terminalia chebula and Allium sativum on in vivo methane emission by sheep.Crossref | GoogleScholarGoogle Scholar | 20666858PubMed |

Paul NA, de Nys R, Steinberg PD (2006) Chemical defence against bacteria in the red alga Asparagopsis armata: linking structure with function. Marine Ecology Progress Series 306, 87–101.
Chemical defence against bacteria in the red alga Asparagopsis armata: linking structure with function.Crossref | GoogleScholarGoogle Scholar |

Pawar MM, Kamra DN, Agarwal N, Chaudhary LC (2014) Effects of essential oils on in vitro methanogenesis and feed fermentation with buffalo rumen liquor. Agricultural Research 3, 67–74.
Effects of essential oils on in vitro methanogenesis and feed fermentation with buffalo rumen liquor.Crossref | GoogleScholarGoogle Scholar |

Payne CL, Scarborough P, Cobiac L (2016) Do low-carbon-emission diets lead to higher nutritional quality and positive health outcomes? A systematic review of the literature. Public Health Nutrition 19, 2654–2661.
Do low-carbon-emission diets lead to higher nutritional quality and positive health outcomes? A systematic review of the literature.Crossref | GoogleScholarGoogle Scholar | 26975578PubMed |

Poornachandra KT, Malik PK, Dhali A, Kolte AP, Bhatta R (2019) Effect of combined supplementation of tamarind seed husk and soapnut on enteric methane emission in crossbred cattle. Carbon Management 10, 465–475.
Effect of combined supplementation of tamarind seed husk and soapnut on enteric methane emission in crossbred cattle.Crossref | GoogleScholarGoogle Scholar |

Ramírez-Restrepo CA, Tan C, López-Villalobos N, Padmanabha J, Wang J, McSweeney CS (2016) Methane production, fermentation characteristics, and microbial profiles in the rumen of tropical cattle fed tea seed saponin supplementation. Animal Feed Science and Technology 216, 58–67.
Methane production, fermentation characteristics, and microbial profiles in the rumen of tropical cattle fed tea seed saponin supplementation.Crossref | GoogleScholarGoogle Scholar |

Rasmussen J, Harrison A (2011) The benefits of supplementary fat in feed rations for ruminants with particular focus on reducing levels of methane production. ISRN Veterinary Science 2011, 613172
The benefits of supplementary fat in feed rations for ruminants with particular focus on reducing levels of methane production.Crossref | GoogleScholarGoogle Scholar | 23738103PubMed |

Ritchie H, Roser M (2019) Meat and dairy production. Our World in Data. Available at https://ourworldindata.org/meat-production [Verified 22 December 2020]

Roque BM, Brooke CG, Ladau J, Polley T, Marsh LJ, Najafi N, Pandey P, Singh L, Kinley R, Salwen JK, Eloe-Fadrosh E (2019a) Effect of the macroalgae Asparagopsis taxiformis on methane production and rumen microbiome assemblage. Animal Microbiome 1, 3
Effect of the macroalgae Asparagopsis taxiformis on methane production and rumen microbiome assemblage.Crossref | GoogleScholarGoogle Scholar | 33499933PubMed |

Roque BM, Salwen JK, Kinley R, Kebreab E (2019b) Inclusion of Asparagopsis armata in lactating dairy cows’ diet reduces enteric methane emission by over 50 percent. Journal of Cleaner Production 234, 132–138.
Inclusion of Asparagopsis armata in lactating dairy cows’ diet reduces enteric methane emission by over 50 percent.Crossref | GoogleScholarGoogle Scholar |

Roque BM, Van Lingen HJ, Vrancken H, Kebreab E (2019c) Effect of Mootral: a garlic- and citrus-extract-based feed additive: on enteric methane emissions in feedlot cattle. Translational Animal Science 3, 1383–1388.
Effect of Mootral: a garlic- and citrus-extract-based feed additive: on enteric methane emissions in feedlot cattle.Crossref | GoogleScholarGoogle Scholar | 32704901PubMed |

Russell JB, Strobel HJ (1989) Effect of ionophores on ruminal fermentation. Applied and Environmental Microbiology 55, 1
Effect of ionophores on ruminal fermentation.Crossref | GoogleScholarGoogle Scholar | 2650616PubMed |

Sasaki D, Morita M, Sasaki K, Watanabe A, Ohmura N (2012) Acceleration of cellulose degradation and shift of product via methanogenic co-culture of a cellulolytic bacterium with a hydrogenotrophic methanogen. Journal of Bioscience and Bioengineering 114, 435–439.
Acceleration of cellulose degradation and shift of product via methanogenic co-culture of a cellulolytic bacterium with a hydrogenotrophic methanogen.Crossref | GoogleScholarGoogle Scholar | 22652087PubMed |

Schmidt HP, Hagemann N, Draper K, Kammann C (2019) The use of biochar in animal feeding. PeerJ 7, e7373
The use of biochar in animal feeding.Crossref | GoogleScholarGoogle Scholar | 31396445PubMed |

Seedorf H, Kittelmann S, Henderson G, Janssen PH (2014) RIM-DB: a taxonomic framework for community structure analysis of methanogenic archaea from the rumen and other intestinal environments. PeerJ 2, e494
RIM-DB: a taxonomic framework for community structure analysis of methanogenic archaea from the rumen and other intestinal environments.Crossref | GoogleScholarGoogle Scholar | 25165621PubMed |

Sen S, Makkar HP, Becker K (1998) Alfalfa saponins and their implication in animal nutrition. Journal of Agricultural and Food Chemistry 46, 131–140.
Alfalfa saponins and their implication in animal nutrition.Crossref | GoogleScholarGoogle Scholar | 10554208PubMed |

Shi J, Arunasalam K, Yeung D, Kakuda Y, Mittal G, Jiang Y (2004) Saponins from edible legumes: chemistry, processing, and health benefits. Journal of Medicinal Food 7, 67–78.
Saponins from edible legumes: chemistry, processing, and health benefits.Crossref | GoogleScholarGoogle Scholar | 15117556PubMed |

Silva RBD, Pereira MN, Araujo RCD, Silva WDR, Pereira RAN (2020) A blend of essential oils improved feed efficiency and affected ruminal and systemic variables of dairy cows. Translational Animal Science 4, 182–193.
A blend of essential oils improved feed efficiency and affected ruminal and systemic variables of dairy cows.Crossref | GoogleScholarGoogle Scholar |

Singh RK, Dey A, Paul SS, Singh M, Punia S (2018) Responses of lemongrass (Cymbopogon citratus) essential oils supplementation on in vitro rumen fermentation parameters in buffalo. Indian Journal of Animal Nutrition 35, 174–179.
Responses of lemongrass (Cymbopogon citratus) essential oils supplementation on in vitro rumen fermentation parameters in buffalo.Crossref | GoogleScholarGoogle Scholar |

Soliva CR, Amelchanka SL, Duval SM, Kreuzer M (2011) Ruminal methane inhibition potential of various pure compounds in comparison with garlic oil as determined with a rumen simulation technique (Rusitec). British Journal of Nutrition 106, 114–122.
Ruminal methane inhibition potential of various pure compounds in comparison with garlic oil as determined with a rumen simulation technique (Rusitec).Crossref | GoogleScholarGoogle Scholar |

Sonoki T, Furukawa T, Jindo K, Suto K, Aoyama M, Sánchez‐Monedero MÁ (2013) Influence of biochar addition on methane metabolism during thermophilic phase of composting. Journal of Basic Microbiology 53, 617–621.
Influence of biochar addition on methane metabolism during thermophilic phase of composting.Crossref | GoogleScholarGoogle Scholar | 22915326PubMed |

Staerfl SM, Zeitz JO, Kreuzer M, Soliva CR (2012) Methane conversion rate of bulls fattened on grass or maize silage as compared with the IPCC default values, and the long-term methane mitigation efficiency of adding acacia tannin, garlic, maca and lupine. Agriculture, Ecosystems & Environment 148, 111–120.
Methane conversion rate of bulls fattened on grass or maize silage as compared with the IPCC default values, and the long-term methane mitigation efficiency of adding acacia tannin, garlic, maca and lupine.Crossref | GoogleScholarGoogle Scholar |

Stewart EK, Beauchemin KA, Dai X, MacAdam JW, Christensen RG, Villalba JJ (2019) Effect of tannin-containing hays on enteric methane emissions and nitrogen partitioning in beef cattle. Journal of Animal Science 97, 3286–3299.
Effect of tannin-containing hays on enteric methane emissions and nitrogen partitioning in beef cattle.Crossref | GoogleScholarGoogle Scholar | 31242504PubMed |

Stoldt AK, Derno M, Das G, Weitzel JM, Wolffram S, Metges CC (2016) Effects of rutin and buckwheat seeds on energy metabolism and methane production in dairy cows. Journal of Dairy Science 99, 2161–2168.
Effects of rutin and buckwheat seeds on energy metabolism and methane production in dairy cows.Crossref | GoogleScholarGoogle Scholar | 26805964PubMed |

Swanson BG (2003) Tannins and polyphenols. In ‘Encyclopaedia of food sciences and nutrition’. (Eds B Caballero, LC Trugo, PM Finglas) pp. 5729–5733. (Academic Press: London, UK)

Tavendale MH, Meagher LP, Pacheco D, Walker N, Attwood GT, Sivakumaran S (2005) Methane production from in vitro rumen incubations with Lotus pedunculatus and Medicago sativa, and effects of extractable condensed tannin fractions on methanogenesis. Animal Feed Science and Technology 123, 403–419.
Methane production from in vitro rumen incubations with Lotus pedunculatus and Medicago sativa, and effects of extractable condensed tannin fractions on methanogenesis.Crossref | GoogleScholarGoogle Scholar |

Tekippe JA, Hristov AN, Heyler KS, Cassidy TW, Zheljazkov VD, Ferreira JFS, Karnati SK, Varga GA (2011) Rumen fermentation and production effects of Origanum vulgare L. leaves in lactating dairy cows. Journal of Dairy Science 94, 5065–5079.
Rumen fermentation and production effects of Origanum vulgare L. leaves in lactating dairy cows.Crossref | GoogleScholarGoogle Scholar | 21943758PubMed |

Terry SA, Ribeiro GO, Gruninger RJ, Vieira Chaves A, Beauchemin KA, Okine E, McAllister TA (2019) A pine enhanced biochar does not decrease enteric CH4 emissions, but alters the rumen microbiota. Frontiers in Veterinary Science 6, 308
A pine enhanced biochar does not decrease enteric CH4 emissions, but alters the rumen microbiota.Crossref | GoogleScholarGoogle Scholar | 31608292PubMed |

Ungerfeld EM (2013) A theoretical comparison between two ruminal electron sinks. Frontiers in Microbiology 4, 319
A theoretical comparison between two ruminal electron sinks.Crossref | GoogleScholarGoogle Scholar | 24198813PubMed |

Ungerfeld EM (2015) Shifts in metabolic hydrogen sinks in the methanogenesis-inhibited ruminal fermentation: a meta-analysis. Frontiers in Microbiology 6, 37
Shifts in metabolic hydrogen sinks in the methanogenesis-inhibited ruminal fermentation: a meta-analysis.Crossref | GoogleScholarGoogle Scholar | 25699029PubMed |

van Zijderveld SM, Gerrits WJJ, Dijkstra J, Newbold JR, Hulshof RBA, Perdok HB (2011a) Persistency of methane mitigation by dietary nitrate supplementation in dairy cows. Journal of Dairy Science 94, 4028–4038.
Persistency of methane mitigation by dietary nitrate supplementation in dairy cows.Crossref | GoogleScholarGoogle Scholar | 21787938PubMed |

van Zijderveld SM, Dijkstra J, Perdok HB, Newbold JR, Gerrits WJJ (2011b) Dietary inclusion of diallyl disulfide, yucca powder, calcium fumarate, an extruded linseed product, or medium-chain fatty acids does not affect methane production in lactating dairy cows. Journal of Dairy Science 94, 3094–3104.
Dietary inclusion of diallyl disulfide, yucca powder, calcium fumarate, an extruded linseed product, or medium-chain fatty acids does not affect methane production in lactating dairy cows.Crossref | GoogleScholarGoogle Scholar | 21605778PubMed |

Villar ML, Hegarty RS, Nolan JV, Godwin IR, McPhee M (2020) The effect of dietary nitrate and canola oil alone or in combination on fermentation, digesta kinetics and methane emissions from cattle. Animal Feed Science and Technology 259, 114294
The effect of dietary nitrate and canola oil alone or in combination on fermentation, digesta kinetics and methane emissions from cattle.Crossref | GoogleScholarGoogle Scholar |

Visioli F, Strata A (2014) Milk, dairy products, and their functional effects in humans: a narrative review of recent evidence. Advances in Nutrition 5, 131–143.
Milk, dairy products, and their functional effects in humans: a narrative review of recent evidence.Crossref | GoogleScholarGoogle Scholar | 24618755PubMed |

Vrancken H, Suenkel M, Hargreaves PR, Chew L, Towers E (2019) Reduction of enteric methane emission in a commercial dairy farm by a novel feed supplement. Open Journal of Animal Sciences 9, 286–296.
Reduction of enteric methane emission in a commercial dairy farm by a novel feed supplement.Crossref | GoogleScholarGoogle Scholar |

Vyas D, Uwizeye A, Mohammed R, Yang WZ, Walker ND, Beauchemin KA (2014) The effects of active dried and killed dried yeast on subacute ruminal acidosis, ruminal fermentation, and nutrient digestibility in beef heifers. Journal of Animal Science 92, 724–732.
The effects of active dried and killed dried yeast on subacute ruminal acidosis, ruminal fermentation, and nutrient digestibility in beef heifers.Crossref | GoogleScholarGoogle Scholar | 24398831PubMed |

Vyas D, McGinn SM, Duval SM, Kindermann M, Beauchemin KA (2016) Effects of sustained reduction of enteric methane emissions with dietary supplementation of 3-nitrooxypropanol on growth performance of growing and finishing beef cattle. Journal of Animal Science 94, 2024–2034.
Effects of sustained reduction of enteric methane emissions with dietary supplementation of 3-nitrooxypropanol on growth performance of growing and finishing beef cattle.Crossref | GoogleScholarGoogle Scholar | 27285700PubMed |

Vyas D, Alemu AW, McGinn SM, Duval SM, Kindermann M, Beauchemin KA (2018) The combined effects of supplementing monensin and 3-nitrooxypropanol on methane emissions, growth rate, and feed conversion efficiency in beef cattle fed high-forage and high-grain diets. Journal of Animal Science 96, 2923–2938.
The combined effects of supplementing monensin and 3-nitrooxypropanol on methane emissions, growth rate, and feed conversion efficiency in beef cattle fed high-forage and high-grain diets.Crossref | GoogleScholarGoogle Scholar | 29741701PubMed |

Wanapat M, Cherdthong A, Pakdee P, Wanapat S (2008) Manipulation of rumen ecology by dietary lemongrass (Cymbopogon citratus Stapf.) powder supplementation. Journal of Animal Science 86, 3497–3503.
Manipulation of rumen ecology by dietary lemongrass (Cymbopogon citratus Stapf.) powder supplementation.Crossref | GoogleScholarGoogle Scholar | 18708607PubMed |

Winders TM, Jolly-Breithaupt ML, Wilson HC, MacDonald JC, Erickson GE, Watson AK (2019) Evaluation of the effects of biochar on diet digestibility and methane production from growing and finishing steers. Translational Animal Science 3, 775–783.
Evaluation of the effects of biochar on diet digestibility and methane production from growing and finishing steers.Crossref | GoogleScholarGoogle Scholar | 32704845PubMed |

Wood JM, Kennedy FS, Wolfe RS (1968) The reaction of multi-halogenated hydrocarbons with free and bound reduced vitamin B12. Biochemistry 7, 1707–1713.
The reaction of multi-halogenated hydrocarbons with free and bound reduced vitamin B12.Crossref | GoogleScholarGoogle Scholar | 4870333PubMed |

Yang K, Wei C, Zhao GY, Xu ZW, Lin SX (2017) Effects of dietary supplementing tannic acid in the ration of beef cattle on rumen fermentation, methane emission, microbial flora and nutrient digestibility. Journal of Animal Physiology and Animal Nutrition 101, 302–310.
Effects of dietary supplementing tannic acid in the ration of beef cattle on rumen fermentation, methane emission, microbial flora and nutrient digestibility.Crossref | GoogleScholarGoogle Scholar | 27272696PubMed |

Yu L, Tang J, Zhang R, Wu Q, Gong M (2013) Effects of biochar application on soil methane emission at different soil moisture levels. Biology and Fertility of Soils 49, 119–128.
Effects of biochar application on soil methane emission at different soil moisture levels.Crossref | GoogleScholarGoogle Scholar |