Future forages: Implications of forage response to climate change for ruminant production

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We will test the hypothesis that growth of forage grass under conditions typical of 2050 UK climate will invoke a stress memory response, negating predicted gains in forage grass quality from targeted breeding. Our central hypothesis is that this will be caused by a combination of plant and microbial factors in the rumen. We hypothesise that the transcriptional and post-transcriptional plant stress responses will alter microbial colonisation profiles, which will result in limited fibre degradation and decreased rumen efficiency. This is based on preliminary data demonstrating effects of forage genotype on rumen efficiency and effects pre-harvest stress on the forage transcriptome and rumen metabolome.
1) We will screen current commercial and pre-commercial ryegrass (Lolium perenne) varieties/ lines in vitro. Feed quality (dry mass, nitrogen, carbohydrates etc), fermentation efficiency (CO2, methane and volatile fatty acids), metabolic profile (including volatile organic compounds, VOCs) will be compared under 5 environmental conditions: 1) current, 2) predicted climate for 2050 (CO2 of 500 ppm and a temperature increase of 5oC) and predicted climate plus, 3) 1 week drought, 4) 1 week flood and 5) 2 d heat (40oC).
2) Two contrasting variety/ lines and 2 environment combinations (including control) will be selected for metabolomics and proteomics, transcriptomics, VOC profiles and metagenomics in a system wide network analysis of the perturbations.
3) Continuous flow fermentation will be used to test whether effects of stress memory in the forage can be overcome by adaptation by the rumen microbiota.
4) An animal trial will be used to verify predictions from the in vitro work. To minimise feed requirements small/miniature sheep will be used comparing intake, nitrogen partitioning and methane production when fed ryegrass grown under current or future scenario.
We will deliver markers for breeders to optimise forage for future climate conditions.

Ruminants provide high quality protein from land that can grow grass but cannot grow grain. Farmed grasslands in the UK represent >40 % of all land-area and provide a cost-effective platform to supply protein feed for ruminants. Maintaining productivity as the climate changes is vital to ensuring food supply and choice. Core to this is understanding the causes of inefficiency of ruminant conversion of plant into animal protein and mitigation of consequent environment damage. Improvements in rumen efficiency require improvements in the forage grasses they are fed on. We will deliver information needed to develop the next generation of grasses to optimise ruminant performance for the future climate conditions.
Understanding now how grasses perform as feeds in the near future (2050) is important because of the long timescale of breeding. This work will therefore directly benefit the UK livestock industry worth £6bn pa as well as researchers in plant, microbial and ruminant science.
1) Farmers will benefit from this research by having appropriate choice of climate ready crops to maximise pasture and animal performance under an altered climate and evidence on which to make decisions. This will indirectly contribute to social inclusion and leisure tourism by increasing the profitability and sustainability of pasture based rural life. We will engage with industry practitioners and representatives by attending industry-facing shows and co-operating with the efforts of the Farming Connect Knowledge Exchange Hub (KE Hub, a Welsh Government funded conduit for information from primary research to the farming community in Wales) and Grassland Development Centre (GDC, an extension service working with focus farms to demonstrate best practice), both based at IBERS.
2) This project will benefit forage plant breeders by providing them with information on the traits needed in future climate-appropriate forage varieties, which they can incorporate immediately into current breeding programmes. The molecular data on the response of forage grass incorporating stress memory in the rumen will inform long-term breeding strategies and provide information on biochemical pathways and target genes for breeders to use as markers in their longer-term high-throughput breeding programmes. We will ensure translation of research to product via our links with Germinal Holdings, an international grass seed company.
3) The scientific community will benefit from increased knowledge of the impact of climate change on non-model, perennial crops which are often poorly studied in comparison with annual species. We plan to produce 6 open access papers from this project spanning the continuum from frontier research into transcriptomics to verification in animals.
4) Policy makers on the reduction of greenhouse gas emissions will benefit from the outputs of this project through improved understanding of effects of climate change on forage digestion and hence on the knock on effects for meeting emission targets set for livestock.
5) There will be a strong training aspect in this project. The PDRAs will benefit from experience of a multifaceted project. They will be expected to present the work at conferences and contribute to writing of publications, so developing their career skills.
6) Consumers will benefit from increased sustainability of ruminant farming delivering cost-effective animal protein. The public will also gain from the environmental benefits in addressing ruminant efficiency thus reducing waste production, which contributes to greenhouse gas emissions and run off from fields. Finally, the gains made in animal productivity by correct tailoring of the forage grass varieties in 2050 will potentially reducing land dedicated to grazing that could be used for growing food crops, and hence both directly and indirectly support food security.