Grass to Gas: Strategies to mitigate GHG emissions from pasture-based sheep emissions

GrassToGas will determine appropriate breeding and nutritional management mitigation strategies to reduce GHG in pasture-based livestock systems. The overall aim of the project is to combine international scientific and industry expertise to generate new knowledge and applied solutions for the mitigation of greenhouse gas emissions (GHG) in sheep. The concept relates to the fact that the international sheep breeding community is at different stages of development in the creation of resource populations to generate feed intake and methane emission measurements for sheep. These are needed to specifically provide new breeding solutions for the sheep industry. The GrassToGas partners are using different sensor technologies, measurement protocols and approaches to address the issue of reducing GHG emissions from sheep. Combining and sharing expertise and addressing knowledge gaps through collaboration in GrassToGas will ensure that consensus on the utilisation of key measurement methods as predictors of GHG emissions, feed and forage efficiency can be agreed and adopted at an international level for use in sheep breeding programmes. As the reduction in GHG emissions is a global issue, a trans-national and trans-disciplinary (breeding, nutrition, economic) approach is necessary which will be incorporated into this project by respective partners focussing on key elements of the knowledge gap for pasture-based sheep systems. The objectives are: 1. To validate predictors of feed intake (FI), methane emissions (ME), and prediction of feed efficiency (FE) using precision livestock technologies and including aspects of animal performance (e.g. lamb growth) and body composition as measured by X-ray imaging and including feeding behaviour patterns. 2. Using indigenous (native) and purchased feed sources, compare indoor vs outdoor FE with methane production to determine the links between, a) indoors & outdoors FE, b) indoors vs outdoors ME, c) outdoor FE & ME, d) indoor FE and ME. 3. Investigate the opportunity of using genetics and genomics (animal and microbiome – the microbial community in the rumen linked to their genomic ‘fingerprint’) to reduce methane emissions in pasture-based sheep systems by, a) comparing breed differences in FE and ME, b) comparing divergent selection lines of sheep (for FE measured by residual feed intake, parasite resistance and growth rate) for FI, FE and ME, and c) comparison of genomic biodiversity of microbial rumen contents related to ME as a predictor of animal ME phenotype, and animal genomic information to predict microbiome. 4. Quantify the economic and environmental benefits of, a) more feed-efficient, and b) lower GHG-emitting sheep linked to the microbial population in the rumen. 5. Deliver applied, sustainable solutions to reduce emissions from the most potent of greenhouse gases (methane), for the international sheep breeding community, by bringing together the latest precision livestock monitoring and molecular technology to identify novel selection targets and potentially candidate genes to identify lower GHG-emitting animals that are more feed-efficient.

The overall aim of the project is to combine international scientific and industry expertise to generate new knowledge and applied solutions for the mitigation of greenhouse gas emissions (GHG) in sheep. GrassToGas will identify individual animal, feed and environmental attributes associated with feed and water intake efficiency for pasture-based sheep production systems. The potential impact would be relevant for the mitigation of GHG emissions within 5 - 10 years and beyond, by the application of the results from this project into sheep breeding programmes designed to produce cumulative reductions of GHG emissions of around 1-3% p.a.

1. To validate predictors of feed intake (FI), (N-alkanes, Rumiwatch and other precision livestock (PLF) sensors, grass offtake, Near Infrared (NIR) spectra of faeces and milk), methane emissions (ME), (FI, Portable Accumulation Chamber (PAC) methane/CO2/O2 measurements, Computer Tomography (CT) and post-slaughter rumen measurements) and prediction of feed efficiency (FE) using FI, lamb growth and body composition by CT and ultrasound methods and feeding behaviour patterns. (WP1)(A)
2. Using indigenous (native) and purchased feed sources, compare indoor vs outdoor FE with methane production to determine the links between, a) indoors & outdoors FE, b) indoors vs outdoors ME, c) outdoor FE & ME, d) indoor FE and ME (WP2)(A, S)
3. Investigate the opportunity of using genetics and genomics (animal and microbiome) to reduce methane emissions in pasture-based sheep systems by, a) comparing breed differences in FE and ME, b) comparing divergent selection lines of sheep (for FE measured by residual feed intake, parasite resistance and growth rate) for FI, FE and ME, and c) comparison of genomic biodiversity of microbial rumen contents related to ME as a predictor of animal ME phenotype, and animal genomic information to predict microbiome. (WP3) (A, P)
4. Quantify the economic and environmental benefits of, a) more feed-efficient, and b) lower GHG-emitting sheep linked to their microbiome. (WP3) (S)

5. Deliver applied, sustainable solutions to reduce emissions from the most potent of greenhouse gases (methane), for the international sheep breeding community, by bringing together the latest precision livestock monitoring and molecular technology to identify novel selection targets and potentially candidate genes for further manipulation such as gene editing.