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The role ensiled forage has on methane production in the rumen

Evans B

Animal Department, Hartpury University, Hartpury, Gloucestershire, United Kingdom

E-mail : bhuvaneswari.bibleraaj@uhsm.nhs.uk

DOI: 10.15761/AHDVS.1000143

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Abstract

Methane emitted by ruminants is not only a significant greenhouse gas but a loss in productivity because of the energy lost from the animal. Ensiled forage is fundamental in the nutrition of housed ruminants. Therefore a review of how ensiled forages influences enteric methane provides  an understanding of what mitigation measure are achievable by the producer and what further research is required. Inclusion of forage maize silage in diets has consistently shown 10-20% reductions in enteric methane reductions by numerous studies, however the level of reduction is dependent on the maturity of the forage the forage maize silage is replacing.  Whereas inclusion of legume silages has been shown to have no significant benefits, even though this forage type has less structural carbohydrates than that of the grass silage it has substituted. Grass swards cut at their immature stage have been shown to reduce enteric methane but best practise of ensiling, silage fermentation and feed out is essential for this benefit to be fulfilled. Inoculants using Lactobcillus sp. can assist in doing this and in doing so greater prominance of this mitigation strategy can be given. Going forward the review picks up on further research in areas such as the type of Lactobaciilli sp. used as an innoculent as it may enhnce the rumen fermentation process itself; the use of exogenous fibrolytic enzmes in enhncing the ensiled forage digestability and tannin and saponin rich forages. These strategies have been inconsistent in delivering results or are uneconomically viable. However if research can be directed towards understanding how different methanogenic Archae operate in the rumen and targetted plant breeding of forages containing bioactive componds, then it may be possible to unlock the potential of future enteric methane mitigation approaches. 

Key words

enteric methane, fermentation, forage, quality, ruminant

Introduction

The impact that livestock production has on the environment was highlighted by FAO (2006) [1] in their ‘Long Shadow of Livestock Production’ report, with enteric methane (ECH4) emissions being a key issue. ECH4 produced by methanogenic Archaea in the anaerobic environment of the rumen-reticulum [2] is responsible for approximately 15% of global warming, largely because methane is 25 times more potent than CO2 as a greenhouse gas [3]. The other downside of ECH4 emissions is the energy lost to the animal which brings about production inefficiencies that can be anywhere between 2 and 12 % [4].

The review by Knapp et al. (2014) [5], looking at the opportunities to reduce methane in dairy production, listed nutrition being at the forefront in achieving this goal. Given ruminants require 50% or more forage in their diet to maintain a healthy and effective functioning rumen [6] and the need to balance out annual forage growth patterns with the requirements of the ruminant by ensiling forages [7], then it can be convincingly argued that silage production is integral in the mitigation of enteric methane. Aspects of silage type and mix; silage quality based on ensiled material; the fermentation process it undergoes; silage inoculants and additives; and novel compounds all play a part in reducing ECH4 and are covered in the remainder of the report.

Silage type and mixture

The type and mixture of ensiled forage fed will have a direct effect on the microbial population within the rumen that consequently influence the level of methanogenic bacteria proliferation [8]. Therefore, it is necessary to understand how different ensiled forages affect ECH4.

Forages with a higher amount of dietary starch will favour the amyolytic bacteria population which will result in propionate production so capturing hydrogen in the process and starving the methanogenic bacteria of an essential substrate required for them to operate [9].  In addition, the greater level of propionate in the rumen lowers the rumen pH that is a condition not likened by the methanogenic bacteria, thus the lesser the methanogenic bacteria population the greater the reduction in ECH4. Whereas if the ensiled forage element is structure fibre based, then cellulolytic bacteria predominate with acetic acid being produced alongside hydrogen and a higher pH environment. The result being conditions that allow the rumen methanogenic bacteria to proliferate and consequently an increase in ECH4.

Reviews of ECH4 mitigation in ruminants have documented that ensiled forages with a lesser proportion of structural carbohydrates (cellulose and hemicellulose) will degrade more quickly in the rumen and be digested more readily resulting in lower ECH4 [2,10]. On this basis it is worthwhile considering ensiled legumes as well as high starch forage crops.

Maize silage compared to grass silage

Based on the above rumen nutritional fundamentals it is not surprising there is a large body of evidence of lessening ECH4 with maize silage feeding compared to grass silage [11]. An in-vitro study by Lengowski et al. (2016) [12] examining the differences in rumen microbial population between grass and maize silage, subsequently observed a significant (P<0.05) lesser amount of methane produced with maize silage (77.2 ml.day-1) than with grass silage (117 ml.day-1). This 35% decline in CH4 occurred even though methanogenic bacteria numbers remained the same for both silages. The authors hypothesised the difference arising because of a methanogenic bacterial order change to those of lower methanogenic activity with maize silage; a hypothesis that warrants further examination. 

In-vivo studies have also shown similar outcomes. Van Gastelen et al. (2015) [13] reported an 11% fall based on dry matter intake (DMI) per kg, in ECH4 when 100% grass silage diet was replaced with that of 100% maize silage. Hart et al. (2015) [14] further substantiated these findings in dairy cows by showing that the replacement of grass silage with maize silage was solely responsible for a significant reduction in ECH4. Lettat et al. (2013) [15] showed a similar fall in methane of 13.5% (kgDMI-1) albeit between a diet of 100% alfalfa forage based to one of 100% maize silage.  In contrast, Brask et al. (2013) [16] when studying the effect of grass silage maturity compared to maize silage found no significance in ECH4 produced between young cut ensiled grass versus maize silage in dairy cows when related to organic matter digestion.  

Legume silage compared to grass silage

Legume silages are suggested to have the capacity of decreasing ECH4 compared to grass silages. Legumes are considered more rapidly digested with their smaller proportion of structural carbohydrates and consequently quicker rate of passage through the rumen compared with grasses [17,18].   An actual study to quantify this effect was set out by Hassanat et al. (2014) [19] where complete timothy grass silage in the forage part of the dairy cows’ diet was replaced in several stages with lucerne.  Surprisingly the study suggested a trend of ECH4 increasing as the timothy silage was replaced with lucerne silage (P=0.1). However, when methane was expressed over units of DMI there was no difference and it was concluded that exchanging grass silage with lucerne silage was not a viable strategy in mitigating ECH4. This corresponded with an aspect of another study’s findings which observed no alteration in methane levels when ensiled ryegrass was substituted using either ensiled white and red clover [20].

Silage quality

Literature reports a strong linear decline in ECH4 with increasing DMI [2,21]. Therefore, enhancing the feed intakes of silages by ensuring quality forage going into the clamp and a quality fermentation process both play an important role in the reduction of ECH4 produced.

Maturity of the forage

The maturity of the forage is central in the composition of the ensiled material which is fed out to the ruminant. As a plant matures the proportion of cell contents, the highly digestible of the plant, diminishes at the expense of the cell wall [22]. The cell wall proportion, therefore the amount of structural carbohydrates and lignin, in a forage is quantified using neutral detergent fibre (NDF) analysis technique. It follows that with increasing plant maturity, NDF will increase resulting in lower DMI by the animal [23] and greater cellulolytic bacteria proliferation in the rumen. This in turn will provide a ruminal environment with greater levels of hydrogen and less acidic thus favouring protozoa [24]. These conditions benefit the methanogenic bacteria hence an expected increase ECH4.

Research by Warner et al. [25] examined this reasoning in detail by studying the effect of early mature; medium and late mature grass silage fed to 54 Holstein Friesian cows in milk, at a high forage to concentrate ratio (80:20) on ECH4.  The study overall found feed digestibility decreased with increasing grass maturity along with a decline in DMI. Daily ECH4 on the other hand showed a 6% decline with greater maturity but this was significantly counterbalanced when ECH4 was expressed on a kg per DMI and fat and protein corrected milk basis showing a decline of 7% and 31% respectively. This allowed the authors to conclude that later matured grass material entering the silo greatly lifts the production of ECH4.  This study substantiated the results obtained by Brask et al. [16] in an aspect of the study where ECH4 in lactating dairy cows was measured between grass silage cut three weeks apart which resulted in a 15% NDF lift in the late cut grass. Consequential daily ECH4 was the same between both but when examined on a kg DMI basis levels of daily ECH4 was 6.2% lower for the early compared to the late matured grass silage.  

Maize silage maturation on the other hand has been shown to decrease in a linear fashion (P ≤ 0.020). A study by Hatew et al (2016) [26] examined the levels of methane produced in dairy cows for forage maize at different harvest maturity resulting in increasing dry matters (25%, 28%, 32% and 40%). As a result, ECH4 based on DMI decreased (2.3% to 2%) without the cow performance being hindered.  These findings were not surprising given the starch level in maize silage increases with maturity due to the cob proportion increasing.  Starch constituency has been seen to increase from 25 to 31% for maize silage dry matters of 24 to 32% respectively, but also resulting too in a fall of NDF (47% to 42%) and ADF (28% to 24%) [27]. This study also goes on to explain that a greater proportion of the maize crop’s starch bypasses the rumen and is digested in the small intestine so avoiding any chance of the methanogenic bacteria capturing the energy of this bypass proportion.

Maize silage inclusion in ruminant diets therefore has a significant part to play in reducing enteric methane especially if it is harvested later. However, it must be remembered that the overall impact on the environment must be considered and there is mounting evidence that the benefits of ECH4 reduction by maize silage is offset by land use change. The annual ploughing for forage maize has been shown to release soil sequestered carbon [28].  Also the need balance out the lower CP in maize silage compared to grass/legume silages by importing protein on to farm, which tends to be soyabean meal, again has a huge carbon footprint with the need of land use change to grow ever greater amounts [29]. Therefore, young mature grass silage becomes of greater importance and the necessity for best ensiling practices given the higher crude protein levels in young grass that makes fermentation more difficult [6].  

Silage fermentation

Best practice of silage making involves clamping forages at the optimum dry matter; rapid filling of the silage clamp, expelling oxygen by rolling, immediate sheeting, minimizing undesirable bacteria contamination e.g. Clostridia and inoculating with homofermentive bacteria e.g. Lactobacillus planetarium. All are necessary to establish rapid acidification resulting in the fermentation process being stable which will not revert to a butyric one [30]. This way greater levels of residual sugars; true protein retained (conversely ammonia N decreased) and butyric acid minimized are key factors in maximizing voluntary intakes [6]. Of course, aerobic stability at feed-out becomes essential with high residual sugars being the ideal substrate for aerobic spoilage organisms e.g. yeasts and molds [31]. By managing these important stages of the overall ensiling process DMI can be lifted, consequently mitigation of ECH4 on a per kg DMI basis.  

The role of silage inoculants

Studies have shown that the use of silage inoculants have a positive response in reducing ECH4. Not only the application of inoculants but also the use of formic acid in unfavourable harvesting conditions assist due to improved animal dry matter intakes [32]. This together with resulting increased animal productivity means less ECH4 per unit of DMI or productivity [2].  In addition, studies by Weinberg et al. (2003) [33] and Hindrichsen et al. (2012) [34] have highlighted more favourable anaerobic ruminal fermentation conditions with silage Lactobacillus inoculants becoming part of the rumen microbe ecology so assisting in ruminal buffering and scavenging of oxygen. This idea of greater Lactobacillus plantarum has been supported by microbe DNA detection and fingerprinting with cows consuming inoculant-treated lucerne silage compared to non-inoculated [35]. However, an in-vitro study by Jalč et al. (2004) [36], using an artificial rumen technique (RUSITEC) to examine methane production between non-inoculated grass silage and inoculated with either Lactobacillus fermentum or Enterococcus faecium showed no difference in methane levels between treatments. Given the in-vitro nature of the study it does not account for what differences in DMI and productivity that might have occurred if it had been in-vivo and the possible dilution of methane over these parameters. This is an important aspect missed out by the authors especially when the Lactobacillus inoculated grass silage resulted in significant increase in material degradability (P<0.05) and levels of propionate (P<0.001), both factors known to assist in lifting DMI and therefore animal productivity.  

Other Considerations

Exogenous fibrolytic enzymes (EFEs): Ruminal throughput is very much determined by the proportion of cell wall in the forage therefore influencing daily DMI and consequently ECH4 production intensity. It follows if digestion of the forage cell wall can be speeded up and increased by breaking down the intricate bonds which exist between the components of the cell wall then ECH4 can be mitigated [37,38]. The use of EFEs in doing this becomes an option and studies of their application have shown positive responses in altering the ensiled forage. Colombatto et al. (2004) [39] recorded a significant decrease in NDF and ADF (P<0.05) and an increase in organic matter degradability with in vitro studies when maize silage was treated with EFEs just before ensiling.  Nevertheless, an in-vivo study, although showing significant positive changes in composites relating to digestability when EFEs were added to lucerne and barley whole crop showed no improvement in the performance of early lactation dairy cows [40]. Mendoza et al. (2014) [37] review considering EFEs picks up on these types of inconsistencies with other studies and highlights the cost of such products as being a huge deterrent in their adoption by farmers. However there appears to be a lack of quantifiable findings of use with EFEs on grass silages and their direct impact on methane production.

Ensiled tannin rich forage legumes: Tannin and saponins compounds are found in high concentrations in certain forages, such as sainfoin and have long been identified as reducing enteric methane largely because of their anti-microbial nature [41,10]. Supplementation of concentrated form of tannins although consistent in reducing methane has had serious effects on animals’ DMI and significant losses in production. A study involving a low inclusion rate (163g.day-1 of condensed tannins to lactating dairy cows saw a 16% reduction in methane but worryingly a milk yield drop of 5% and milk solids of 8% [42].  Although these results are unviable, it did demonstrate real potential for ECH4 reduction.

One study that has shown viability has been ensiled sainfoin; a legume rich in tannins. Huyen et al.’s (2016) [43] study of 50% exchange of sainfoin silage with grass silage to lactating dairy cows showed no changes in DMI before and after nevertheless milk yield increased significantly by 9.4% (P=0.042) and methane fell by 5.8% on a kg DMI basis, although not significantly. This study suggests this mitigation strategy is worth pursuing by the use of modern plant breeding technology.  This may be in the form of plant genetics to breed tannin rich sainfoin varieties or other mainstream legumes and to overcome the low yields of sainfoin [44] making it more viable for commercial livestock units.  

Conclusion

ECH4 mitigation via ensiled forages is a welcomed strategy in the livestock industry not just for diminishing its impact as a greenhouse gas but also increasing productivity because of the energy contained in ECH4 not being lost by the animal accompanied by an increase of ensiled forage intakes. Choice of forage type such as maize silage is an easy strategy to employ when ECH4 mitigation is solely considered but needs to be questioned when full associated greenhouse gas production is taken into account. The role of harvesting early cut swards for ensiling is another strategy and needs greater prominence as a mitigation strategy. However, execution of best practise of ensiling and feed out is essential for it to be effective. The ensiling fermentation process can be assisted with Lactobacillus inoculants and can in their own right enhance the rumen’s ecology and environment to assist in the mitigation of ECH4.

Future considerations for ECH4 mitigation could involve understanding how different strains of methanogenic Archea operate with different forages and exploring if there is anyway of manipulating them. Forages containing bioactive compounds also show promise and with the use of plant breeding may be a means of making this strategy practical at farm level.   By making sure future strategies are functional on farm and highlighting the importance forage type, maturation and the precision of ensiling forages has on the reduction of ECH4 then mitigating the impact of livestock on the environment can be attained. 

References

  1. Food and Agriculture Organisation (2006) Livestock’s long shadow: environmental issues and options.
  2. Firkins J, Lee C, Tricarico JM, Dijkstra J, Yang W, et al. (2013) Mitigation of methane and nitrous oxide emissions from animal operations: I. A review of enteric methane mitigation options. J Anim Sci 91: 5045-5069.
  3. Pereira LGR, Machado FS, Campos MM, Júnior RG, Tomich TR, et al. (2015) Enteric methane mitigation strategies in ruminants: a review. Revista Colombiana de Ciencias Pecuarias 28: 124-143.
  4. Martin C, Morgavi DP, Doreau M (2010) Methane mitigation in ruminants: from microbe to the farm scale. Animal 4: 351-365. [Crossref] 
  5. 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. J Dairy Sci 97: 3231-3261. [Crossref]
  6. McDonald P, Edwards RA, Greenhalgh JFD, Morgan CA, Sinclair LA, et al. (2011) Animal Nutrition (7th edition). Hadlow: Pearson.
  7. Holmes W (1982) Grass its production and utilisation. Billing and Sons Ltd, Worcester.
  8. Beckman JL, Weiss WP (2005) Nutrient digestibility of diets with different fiber to starch ratios when fed to lactating dairy cows. J Dairy Sci 88: 1015-1023. [Crossref]
  9. Meale SJ, McAllister TA, Beauchemin KA, Harstad OM, Chaves AV (2012) Strategies to reduce greenhouse gases from ruminant livestock. Acta Agriculturae Scandinavica 62: 199-211.
  10. Hristov AN, Oh J, Firkins JL, Dijkstra J, Kebreab E, et al. (2013) Special Topics- Mitigation of methane and nitrous oxide emissions from animal operations: I. A review of enteric methane mitigation options1. J Anim Sci 91: 5045.
  11. Patra AK (2012) Enteric methane mitigation technologies for ruminant livestock: a synthesis of current research and future directions. Environ Monit Assess 184: 1929-1952. [Crossref]
  12. Lengowski MB, Zuber KHR, Witzig M, Möhring J, Boguhn J, Rodehutscord M (2016) Changes in Rumen Microbial Community Composition during Adaption to an In Vitro System and the Impact of Different Forages. PLoS One 11: e0150115. [Crossref]
  13. Van Gastelen S, Antunes-Fernandes EC, Hettinga KA, Klop G, Alferink SJJ, et al. (2015) Enteric methane production, rumen volatile fatty acid concentrations, and milk fatty acid composition in lactating Holstein-Friesian cows fed grass silage-or corn silage-based diets. J Dairy Sci 98: 1915-1927.
  14. Hart KJ, Huntington JA, Wilkinson RG, Bartram CG, Sinclair LA (2015) The influence of grass silage-to-maize silage ratio and concentrate composition on methane emissions, performance and milk composition of dairy cows. Animal 9: 983-991. [Crossref]
  15. Lettat A, Hassanat F, Benchaar C (2013) Corn silage in dairy cow diets to reduce ruminal methanogenesis: effects on the rumen metabolically active microbial communities. J Dairy Sci 96: 5237. [Crossref]
  16. Brask M, Lund P, Hellwing ALF, Poulsen M, Weisbjerg MR (2013) Enteric methane production, digestibility and rumen fermentation in dairy cows fed different forages with and without rapeseed fat supplementation. Anim Feed Sci and Techn 184: 67-79.
  17. Dewhurst RJ (2012) Milk production from silage: Comparison of grass, legume and maize silages and their mixtures. In: K. Kuoppala, M. Rinne, and A. Vanhatalo, editors, Proc. XVI Int. Silage Conference. MTT Agrifood Research Finland, University of Helsinki. Hameenlinna, Finland 134-135.
  18. Barnes RF, Nelson J, Moore KJ, Collins M (2003) Forages, an introduction to grassland agriculture; Volume I (Sixth Edition). Ames, Iowa and Oxford: Blackwell Publishing.
  19. Hassanat F, Gervais R, Massé DI, Petit HV, Benchaar C (2014) Methane production, nutrient digestion, ruminal fermentation, N balance, and milk production of cows fed timothy silage- or alfalfa silage-based diets. J Dairy Sci 97: 6463. [Crossref]
  20. Van Dorland HA, Wettstein H, Leuenberger H, Kreuzer M (2007) Effect of supplementation of fresh and ensiled clovers to ryegrass on nitrogen loss and methane emission of dairy cows. Livestock Sci 111: 57-69.
  21. Cottle DJ, Nolan JV, Wiedemann SG (2011) Ruminant enteric methane mitigation: A review. Anim Prod Sci 51: 491-514.
  22. Chagunda MGG, Flockhart JF, Roberts DJ (2010) The effect of forage quality on predicted enteric methane production from dairy cows. Intern J of Agri Sustain 8: 250-256.
  23. Rinne M, Huhtanen P, Jaakkola S (2002) Digestive processes of dairy cows fed silages harvested at four stages of grass maturity. J Anim Sci 80: 1986-1998.
  24. Boadi D, Benchaar C, Chiquette J, Masse D (2004) Mitigation strategies to reduce enteric methane emissions from dairy cows: update review. Canadian J Anim Sci 84: 319-335.
  25. Warner D, Klop G, Bannink A, Podesta SC, Dijkstra J, et al. (2016) Effects of nitrogen fertilisation rate and maturity of grass silage on methane emission by lactating dairy cows. Animal 10: 34-43. [Crossref]
  26. Hatew B, Bannink A, Laar van H, Jonge de LH, Dijkstra J (2016) Increasing harvest maturity of whole-plant corn silage reduces methane. J Dairy Sci 99: 354-368. [Crossref]
  27. Fernandez I, Noziere P, Michalet-Doreau B (2004) Site and extent of starch digestion of whole-plant maize silages differing in maturity stage and chop length, in dairy cows. Livestock Prod and Sci89:  147-157.
  28. Vellinga TV, Hoving IE (2011) Maize silage for dairy cows: mitigation of methane emissions can be offset by land use change. Nutri Cycl Agroecosys 89: 413-426.
  29. Hörtenhuber SJ, Lindenthal T, Zollitsch W (2011) Reduction of greenhouse gas emissions from feed supply chains by utilizing regionally produced protein sources: the case of Austrian dairy production. J Sci Food Agric 91: 1118-1127. [Crossref]
  30. Charmley E (2001) Towards improved silage quality – a review. Canadian J Anim Sci. 81: 157-168.
  31. Wilkinson JM, Davies DR (2012) The aerobic stability of silage: key findings and recent developments. Grass and Forage Sci 68: 1-19.
  32. Navarro-Villa A, O'Brien M, López S, Boland TM, O'Kiely P (2013) In vitro rumen methane output of grasses and grass silages differing in fermentation characteristics using the gas-production technique (GPT). Grass and Forage Sci 68: 228-244.
  33. Weinberg ZG, Muck RE, Weimer PJ (2003) The survival of silage inoculant lactic acid bacteria in rumen fluid. J Appl Microbiol 94: 1066-1071. [Crossref] 
  34. Hindrichsen IK, Augustsson EU, Lund B, Jensen MM, Raun M, et al. (2012) Characterisation of different lactic acid bacteria in terms of their oxygen consuming capacity, aerobic stability and pathogen inhibition. In: K. Kuoppala, M. Rinne, and A. Vanhatalo, editors. Proc. XVI Int. Silage Conf. MTT Agrifood Research Finland. University of Helsinki. Hameenlinna, Finland 105-106.
  35. Mohammed R, Stevenson DM, Beauchemin KA, Muck RE, Weimer PJ (2012) Changes in ruminal bacterial community composition following feeding of alfalfa ensiled with a lactic acid bacterial inoculant. J Dairy Sci 95: 328-339. [Crossref]
  36. Jalc, D, Lauková A, Váradyová Z, Homolka P, Koukolová V (2009) Effect of inoculated grass silages on rumen fermentation and lipid metabolism in an artificial rumen (RUSITEC). Animal Feed Science and Technology 151: 55-64.
  37. Mendoza GD, Loera-Corral O, Plata-Pérez FX, Hernández-García PA, Ramírez-Mella M (2014) Considerations on the Use of Exogenous Fibrolytic Enzymes to Improve Forage Utilization. Scientific World J 247437.
  38. Chung Y, Zhou M, Holtshausen L, Alexander TW, McAllister TA, et al. (2012) A fibrolytic enzyme additive for lactating Holstein cow diets: Ruminal fermentation, rumen microbial populations, and enteric methane emissions. J Dairy Sci 95: 1419-1427. [Crossref]
  39. Colombatto D, Mould FL, Bhat MK, Phipps RH, Owen E (2004) In vitro evaluation of fibrolytic enzymes as additives for maize (Zea mays) silage. Anim Feed Sci and Techn 111: 145-159.
  40. Holtshausen L, Chung Y, Gerardo-Cuervo H, Oba M, Beauchemin KA (2011) Improved milk production efficiency in early lactation dairy cattle with dietary addition of a developmental fibrolytic enzyme additive. J Dairy Sci 94: 899-907. [Crossref]
  41. Jayanegara A, Wina E, Takahashi J (2014) Meta-analysis on Methane Mitigating Properties of Saponin-rich Sources in the Rumen: Influence of Addition Levels and Plant Sources. Asian-Australas J Anim Sci 27: 1426-1435. [Crossref]
  42. Grainger C, Clarke T, Auldist MJ, Beauchemin KA, McGinn SM, et al. (2009) Potential use of Acacia mearnsii condensed tannins to reduce methane emissions and nitrogen excretion from grazing dairy cows. Canadian J Anim Sci 89: 241-251.
  43. Huyen NT, Desrues O, Heniks WH, Verstegen MWA, Alferink SJJ, et al. (2015) Inclusion of sainfoin (Onobrychis viciifolia) silage in dairy cow rations affects nutrient digestibility, nitrogen utilization, energy balance, and methane emissions. J Dairy Sci 99: 3566-3577. [Crossref]
  44. Francis S (2005) British Field Crops: A Pocket Guide to the Identification, History and Uses of Traditional and Novel Arable Crops in Great Britain. Bury St Edmunds, Moreton Hill Press.

Editorial Information

Editor-in-Chief

Article Type

Review Article

Publication history

Received date: October 03, 2018
Accepted date: October 12, 2018
Published date: October 16, 2018

Copyright

© 2018 Evans B. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Citation

Evans B (2018) The role ensiled forage has on methane production in the rumen. Anim Husb Dairy Vet Sci 2: DOI: 10.15761/AHDVS.1000143

Corresponding author

Evans B

Animal Department, Hartpury University, Hartpury, Gloucestershire, UK

E-mail : bhuvaneswari.bibleraaj@uhsm.nhs.uk

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