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

镁（Mg）在活细胞的许多基本过程中起重要作用，因此对动物健康至关重要。在像牛羊这样的反刍动物中，低镁状态（低镁血症）会引起手足颤或蹒跚。这些情况在欧洲的反刍动物中非常普遍，通常具有很高的死亡率。因此，避免低镁血症对动物福利和农场业务盈利能力至关重要。通常情况下，这种情况是通过使用饲料混合物或膳食补充剂或直接将Mg作为药物给予动物来控制的。然而，这些方法成本高昂，效率低下。另一种方法是确保野外动物吃的草或作为干草或青贮饲料吃的草能提供镁的良好来源。这种方法在英国农业中还不发达，饲草肥料管理也是如此。开发这些方法需要三个方面的进展。首先，我们必须了解土壤供应镁的能力的自然变化，这是由全国各地土壤性质和岩石组成的差异造成的。其次，我们必须了解目前农民如何在一系列企业中使用镁作为补充剂、添加剂、肥料和兽医干预措施。第三，我们必须了解镁从土壤到植物再到动物的转移机制，以及如何利用这些机制。例如，植物育种家在20世纪70/80年代选择了镁含量较高的牧草品种。例如，在英国育种计划中选择了积累更多Mg的意大利黑麦草（Lolium multiflorum 'Magnet/RVP2067'）品种。该品种在不同地点表现一致，并在饲养研究中被证明可以改善反刍动物的Mg状态。然而，这一特性并没有在现代杂交或多年生黑麦草品种中得到追求，现在受到该部门的青睐。我们的目标是为英国反刍动物部门的Mg开发新的和有弹性的营养管理策略。该项目的主要营养重点是Mg，因为它对英国反刍动物部门具有战略重要性。然而，该项目产生的新数据、知识以及管理和沟通工具将适用于对动物健康很重要的其他营养素/元素。因此，该项目将具有更大的潜力，可以提高动物生产的效率和弹性，并将增进我们对景观尺度过程的更广泛理解。该项目将利用一系列科学学科，包括土壤化学、地质学、统计学、经济学和植物科学。四个主要目标是：(1)利用不同的土壤数据绘制英格兰、北爱尔兰和威尔士地区的地图，这些地区的土壤中Mg的供应可能不足；(2)对农场中的Mg转移及其管理方式有新的认识；(3)开发遗传标记和作物管理策略，以提高现代牧草的叶片Mg浓度；(4)将这些知识和信息流整合到一个决策工具中，使农民能够在农场规模上改进饲料营养管理，并帮助顾问或政策制定者审查区域规模的管理方案。该工具将考虑到根据当地和区域土壤条件，通过矿物质补充或通过增强营养饲料剖面来改善放牧管理的营养管理方案的经济影响。决策支持将通过用户友好的网络/智能手机界面提供。用户定义的输入将包括空间数据（土壤特征、气候等）、草品种的选择、肥料管理、补充使用和经济成本。产出将使各种镁营养方案的经济效益能够在农场到区域的范围内进行比较和交流。

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.