Magnesium Network (MAG-NET): Integrating Soil-Crop-Animal Pathways to Improve Ruminant Health

Magnesium (Mg) plays an important role in many basic processes in living cells, and is therefore essential for animal health. Low Mg status (hypomagnesaemia) gives rise to conditions called tetany, or staggers, in ruminants like cattle and sheep. These conditions are remarkably widespread among ruminants in Europe, often with high fatality rates. Avoiding hypomagnesaemia is therefore important for animal welfare and farm business profitability. Typically the condition is managed by use of feed mixes or dietary supplements or by directly administering Mg to animals as a medicine. However, these approaches are costly and can be inefficient and ineffective. Another approach is to ensure that the grass grazed by animals in the field or eaten as hay or silage provides a good source of Mg. This approach is under-developed in UK agriculture, as is forage fertilizer management.

To develop these approaches requires three advances. First, we must understand the natural variation in the capacity of the soil to supply Mg, caused by differences across the country in the properties of the soil and the composition of the rocks from which they are derived. Second, we must understand how farmers currently use Mg in a range of enterprises as supplements, additives, fertilizers and veterinary interventions. Third, we must understand the mechanisms by which Mg is transferred from soil to plant to animal and how these can be exploited. For example, forage grass varieties that accumulate more Mg were selected by plant breeders in the 1970/80s. For example, a variety of Italian ryegrass (Lolium multiflorum 'Magnet/RVP2067') which accumulates more Mg was selected in UK breeding programmes. This variety performed consistently across sites and was shown to improve ruminant Mg status in feeding studies. However, this trait has not since been pursued in modern hybrid or perennial ryegrass varieties now favoured by the sector.

We aim to develop novel and resilient nutrient management strategies for Mg in the UK ruminant sectors. The primary nutritional focus of this project is Mg due to its strategic importance to the UK ruminant sector. However, new data, knowledge and management and communication tools arising from this project will apply to other nutrients/elements which are important for animal health. The project will therefore have wider potential to make animal production more efficient and resilient and will improve our wider understanding of landscape-scale processes.

This project will draw on a range of scientific disciplines including soil chemistry, geology, statistics economics and plant sciences. The four primary objectives are: (1) to use varied soil data to map the regions of England, N. Ireland and Wales where the soil supply of Mg is likely to be insufficient (2) to develop new understanding of Mg transfers on the farm and how these are managed, (3) to develop genetic markers and crop management strategies to increase leaf Mg concentration in modern forage grasses, and (4) to integrate these streams of knowledge and information into a decision tool that allows the farmer to improve forage nutrient management at farm scale and also help advisors or policy makers to examine management options at regional scale. The tool will take into account the economic impact of nutrient management scenarios based upon delivery via mineral supplements or improved grazing management via enhanced nutritional forage profiles given local and regional soil conditions.

Decision support will be delivered via a user-friendly web/smart-phone interface. User-defined inputs will include spatial data (soil characteristics, climate, etc.), choice of grass variety, fertiliser-management, supplement use, and economic costs. Outputs will enable the economic benefits of the various Mg nutrition options to be compared and communicated, at farm-to-regional scales.

We aim to develop novel, resilient nutrient management strategies for the UK ruminant sector. The primary focus is magnesium (Mg) due to its strategic importance to the ruminant sector. However, new data, knowledge and communication tools arising from this project will apply to other nutrients/elements, to support more resilient production systems and to improve our wider understanding of landscape-scale processes. The primary objectives (deliverables) are:


1. Predictive maps of hypomagnesaemia-sensitive regions for England, N. Ireland and Wales. These will be developed from high-resolution public data on soil nutrient concentrations, geochemistry and land-use, and soil/crop data in large private-sector databases. Data will be integrated, and risks communicated, using geospatial modelling, and tested by on-farm audits.

2. Farm and veterinary audit of magnesium use, knowledge and opinion. Questionnaire surveys and detailed on-farm audits (soil, forage, fodder, animal biomarkers) will be used in areas of predicted high and low available Mg for dairy, beef and sheep sectors.

3. Novel genetic markers and crop management strategies to increase leaf Mg concentration in forage grasses. Genetic markers will be obtained from an Italian ryegrass cultivar (Magnet/Bb2067) with high leaf Mg concentration. A panel of modern hybrid and perennial ryegrass cultivars will be screened for the presence of these markers and new pre-breeding material will be developed. The response of Magnet/Bb2067 to Mg fertilisation will be tested in the field.

4. A multi-scale decision support tool for farm nutrient management. A web/smart-phone application will be developed. Inputs will include geospatial data (soil characteristics, climate, etc.), cultivar-choice, fertiliser-management, supplement use, and economic costs. Outputs will enable the economic benefits of nutrition management options to be compared and communicated, at farm-to-regional scales.

Magnesium (Mg) is an essential element for livestock and Mg deficiency (hypomagnesaemia) causes economic losses to farm businesses. Improving our understanding of dietary flows of Mg and other elements through the soil-crop-animal pathway, at farm to regional scales, can potentially reduce these economic losses. It is widely recognised that 'nutritionally-informed' management strategies have great potential for UK dairy (worth £3.9b/yr) and sheep (worth £1b/yr) sectors. Thus, even marginal on-farm nutrient efficiency gains could deliver substantial economic and social impact. However, such strategies remain a significant and multidisciplinary challenge, requiring strategic R&D. Here, we aim to improve nutrient management efficiency within the UK agriculture sector using Mg as an exemplar element.

An integrated 'Pathways to Impact' plan is embedded within all Work Packages (WPs). The primary activity is direct and ongoing engagement with industry, including project partners (agronomy, fertiliser, veterinary sectors), farming representative bodies, and SARIC stakeholders. Subsidiary activities include academic interactions among soil, crop and livestock scientists, agricultural economists, and staff/student training.

Measurable immediate impact will be realised for partners and SARIC stakeholders by delivering: (1) integrated private- and public-sector soil and crop element-composition data for mapping/modelling (WP1); (2) on-farm audits developed with XLVets, representing 30% of UK farm animal practices, thereby enabling adequate survey participation and engagement by farmers (WP2); (3) marker-testing in germplasm owned by Germinal Seeds (WP3).

For impact to the wider sector, including policy makers, the effective communication of results is essential and a full WP (WP4) is devoted to communication activities. Thus, in WP4, a multi-scale decision support tool for nutrient management will be delivered via a user-friendly interface (web/smart-phone application). Inputs will include geospatial data (soil characteristics, climate, etc.), cultivar-choice, fertiliser-management, supplement use, and economic costs. Outputs will enable the economic benefits of the nutritional options to be compared and communicated, at farm-to-regional scales. Delivering comprehensible, yet meaningful, results to the farming sector will draw on current best practice in risk communication. For example, Murray Lark and colleagues at British Geological Survey (BGS) recently developed a framework for managing and communicating risks of cobalt (Co) deficiency in Irish soils, applying verbal and numerical scales of uncertainty of likely outcomes to support farm-to-regional scale advice. Such an approach will be developed further in this project

New web-mapping services developed in this project will also be uploaded onto existing NERC/BBSRC/partner mapping platforms, such as the free app mySoil and the web-portal UK Soil Observatory, to improve data-legacy. In addition to map-based communication, impact will be pursued via activities including: (1) industry events (e.g. Grassland & Muck, May 2017); (2) corporate newsletters/publications; (3) industry training (e.g. XLVets hold regular training for improving farm-animal health management).

Impact is also expected from academic and training activities. Academic impact (e.g. via publications, talks etc.) will be enhanced by interactions with industry-scientists, which leverages specialist expertise, unique data (e.g. soil analyses), and physical resources (e.g. livestock bloods and urines, germplasm, soil samples) within this project. Impact via staff training will exploit tri-directional training opportunities between academic, research institute, and industry sectors. Impact via student training will encompass undergraduate, postgraduate and placement students.