Greenhouse in Agriculture - Dietary Supplements for enteric methane abatement

Enteric methane abatement strategies for ruminant production systems in SE Australia

Expected Outcomes:

Quantified methane abatement strategies for ruminant production systems in SE Australia consistent with maintaining profitable and viable livestock production.

Project Objectives:

  • Evaluate forages and dietary supplements for methane mitigation and production impacts
  • Evaluate Open Path Tracer methods for measurement of methane from grazing ruminants

Enteric methane contributes c. 11% of national greenhouse gas emissions, the majority of which comes from beef, sheep and dairy cattle. In south eastern Australia, these three industries mainly occupy relatively high rainfall, improved pasture zones or feedlots, where dietary and management interventions for reducing methane are more feasible than in extensive rangeland zones.

This project is part of the national Reducing Methane Emissions from Livestock Program and is funded by DAFF, Meat and Livestock Australia and Dairy Australia.

 Mitigation

This Project builds on previous research on the impacts of various dietary supplements on methane mitigation potential for ruminants. An early element of this Project is to conduct workshop with key members of the MLA-methane program consortium to establish a national approach to in vitro screening of various forage options (drawing on forages evaluated in the 30:30 and EverGraze projects and other sources), plus a range of dietary supplements (oils/fats, tannin extracts, forage tannins, nitrates, probiotics, and cellulosic enzymes) for their methane abatement potential.  The team will continually review and evaluate further options, like the practicality of sourcing oils from micro-algae, nitrates and cost-effective sources of tannins and enzymes. All options evaluated will include an assessment of practical, ethical and cost-effective means of feeding to grazing ruminants.  

From in vitro screening, promising forages and supplements will then be tested in vivo using the SF6 method in the field, with the Open Circuit Respiration Chambers (being more definitive, but also expensive and limited in treatment combinations) then being the last step in definitively quantifying the methane abatement potential of the most promising sub-set of these options. Initial methane measurements will focus on oils and tannins already identified. The Project aims to run these various stages of evaluation concurrently, to ensure that new options are progressing in their evaluation throughout the life of the Project. Certain oils, tannins, forages and enzymes have already been identified in prior research, and these will be evaluated directly using SF6 and chambers, concurrently with in vitro screening of prospective options. 

An integral part of both field testing with SF6 and measurement in the chambers will be quantifying production impacts of the various options, including estimates of Dry Matter intake, milk production, milk composition and functionality, and/or live weight change. Initially all evaluations will use dairy cows at Ellinbank, as milk production is the most sensitive indicator of a production impact and Ellinbank has over 30 fistulated cows available for essential rumen sampling. This will assist in keeping experimental periods shorter (and more cost-effective) than if weight gain or wool production were used as assessments of production impacts. Where appropriate (eg. Tannins) full energy and nitrogen balances will also be conducted in either metabolism stalls or in the chambers, to understand the impacts on urine and dung N excretion, plus energy and protein balance.

In partnership with CSIRO Livestock Industries, the impacts of various forages and supplements on rumen micro-floral populations will be studied to understand the mechanism of action of abatement strategies, thus providing confidence of the longevity/sustainability of enteric methane abatement options. DNA profiling of rumen microbiota will be conducted in collaboration with SARDI, to identify differences in gut/rumen contents in relation to methane emissions from ruminants. 

Measurement

This Project will establish and validate the Open Path FTIR method, including defining the limitations and appropriate application of this method for use with animals grazing in paddocks. Further comparison will be made between methane measured from cattle in planned SF6 experiments and the Open Path FTIR method. The aim of this work will be to evaluate the Open Path FTIR method as a recognised and standard method for measuring methane from grazing ruminants. This proposal includes capital (jointly from VDPI and DAFF) to purchase and construct a second Open Path FTIR system which is necessary to conduct this research.

On farm demonstration

This Project will work with local and regional groups in collaboration with MLA and DAFF to contribute to Information Integration and Delivery (B.CCH.1040) and Demonstration (B.CCH.1030) Projects in the Reducing Methane Emissions from Livestock Program.   Potential groups include; Bass Coast Landcare, Western Port Greenhouse Alliance, South West Climate Change Forum and EverGraze. These regional groups are working with farmers to demonstrate practical abatement strategies on farm.

Apart from the publication of results in reports, peer reviewed papers and journals, the Project will use the existing networks and evaluation processes currently established within Victoria, plus the information delivery Project established as part of the Reducing Emissions from Livestock Program.  

Start date: 1 April, 2009         Completion date: 1 December, 2011

   
   
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