Exploiting plant diversity and phenology for livestock health under climate change

气候变化给牲畜放牧系统带来了严重的挑战，无论是减缓还是适应。立法和消费者的关注日益优先考虑环境影响。同时，气候变暖有利于增加疾病威胁，就像抗菌素耐药性威胁到化学控制的有效性一样。更多样化地利用植物资源有可能解决其中的一些挑战：例如，灌木和树木等根系较深的植物增加了碳封存，减少了极端降雨事件造成的水和养分流失，并提供具有抗寄生虫作用的营养饲料，减少了对化学除虫剂的依赖[2,3]。效益没有充分实现，因为与温暖地区的银牧系统相比，它们在英国的主流牲畜系统中特征不佳。此外，尽管将树木整合到以草为基础的系统中会带来恢复力和生态效益，但生产效率可能在短期内降低，从而抑制吸收。该项目提出了一个假设，即将植物物候与季节性寄生虫风险结合起来，可以提高基于树木的疾病威胁解决方案的有效性，从而提高其经济价值。目标围绕农田树木的三种不同但互补的生态系统服务进行组织，重点是寄生虫控制，植物物候作为寄生虫风险的指标。因为植物利用气候线索触发季节事件（=物候学），这些事件可以预测寄生虫感染的风险期。春季冲刷虫巴氏线虫（Nematodirus battus）在土壤温度升高时出现，秋季土壤温度下降到一定范围时再次出现。将从《自然日历》（英国物候网络）中提取英国树木和林地/灌木篱植物物种的叶片破裂、开花和落叶日期的年度数据，并与VIDA兽医实验室数据库[5]中的白头野鼠爆发记录进行比较。研究结果将验证一种假设，即特定植物的春季和秋季事件可以预测特定年份和地点的疾病风险，并支持农民的治疗决策。树木饲料是一种有针对性的营养资源。通过减少寄生虫在肠道中的建立和存活，通过保护蛋白质免受瘤胃降解，从而纠正被寄生动物的蛋白质损失，以及通过饮食替代污染更严重的低矮植物（如草）来减轻寄生虫的影响。然而，长期单独使用它们的营养价值往往很低，而且单宁浓度过高会降低采食量和消化能力。将分析白蜡树、苹果和柳叶的单宁浓度和化学结构，包括生长期间、落叶或干燥后的单宁浓度、化学成分、有效蛋白质能量含量和体外抗寄生虫功效。结果将校正饲料篮配方，以便在寄生虫风险的关键时期有针对性地补充树木饲料（例如，夏季灌木林或pollard用于早期抑制寄生虫；落叶用于去除后期耐药蠕虫）。将在瘤胃模拟器中评估所选混合物的消化率和排放物，并在饲养试验中评估其适口性。传播模型[7]将评估有针对性的季节性干预对寄生虫流行病学和耐药性选择的影响。树蝇中寄生虫传播的改变。树木改善排水和土壤结构，可能减少寄生虫的传播；而遮阳和动物聚集可以增加寄生虫的可用性。净效应可能是复杂的，并影响如何最好地规划和利用牧场上的树木。该组件将测量寄生虫及其环境相关因素（易位粪便周围的线虫幼虫密度；肝吸虫夏季土壤饱和度）

Climate change presents serious challenges to livestock grazing systems, both for mitigation and adaptation. Legislative and consumer concerns increasingly prioritise environmental impacts. Simultaneously, climate warming favours increased disease threats just as antimicrobial resistance threatens the effectiveness of chemical control [1]. More diverse utilisation of plant resources has the potential to address several of these challenges: for example, deep-rooted plants such as shrubs and trees increase carbon sequestration, reduce water and nutrient run-off from extreme rainfall events, and provide nutritious fodder with proven antiparasitic effects, reducing reliance on chemical de-wormers [2,3]. Benefits are insufficiently realised because they are poorly characterised for mainstream livestock systems in the UK, compared with silvo-pastoral systems in warmer regions. Further, although integrating trees into grass-based systems confers resilience and ecological benefits, production efficiency could decrease in the short term, inhibiting uptake. This project addresses the hypothesis that aligning plant phenology with seasonal parasite risks can enhance the effectiveness of tree-based solutions to disease threats, and hence their economic value. The objectives are organised around three distinct but complementary ecosystem services from trees on farmland, focusing on parasite control Plant phenology as an indicator of parasite risk. Because plants use climatic cues to trigger seasonal events (=phenology), such events might predict risk periods for parasite infection. The spring scour worm Nematodirus battus emerges in response to rising soil temperature, and again in autumn when soil temperature falls to within a defined range [4]. Annual data on dates of leaf burst, flowering and leaf fall for UK tree and woodland/hedgerow plant species will be extracted from Nature's Calendar (UK Phenology Network) and compared with records of N. battus outbreaks from the VIDA veterinary laboratory database [5]. Results will test the hypothesis that spring and autumn events in particular plants can predict disease risk in a given year and location, and support treatment decisions by farmers.Tree fodder as a targeted nutritional resource. Tanniferous tree leaves attenuate parasite impacts by reducing establishment and survival in the gut, by protecting protein from rumen degradation and consequently correcting protein loss in parasitized animals, and by dietary displacement of more highly contaminated lower-growing plants such as grasses [3]. Used alone over sustained periods, however, their nutritional value is often low, and excessively high tannin concentrations reduce feed intake and digestion. Tannin concentration and chemical structure will be analysed for ash, apple and willow leaves, during growth and after leaf-fall or drying, with chemical composition, available protein-energy content, and in-vitro antiparasitic efficacy. Results will calibrate feed basket formulation for targeted tree fodder supplementation at key times of parasite risk (e.g. summer coppice or pollard for early season parasite suppression; fallen leaves for removal of late-season drug-resistant worms). Selected mixes will be evaluated for digestibility and emissions in rumen simulators, and for palatability in feeding trials. Transmission models [7] will evaluate consequences of targeted seasonal intervention for parasite epidemiology and selection of drug resistance.Modification of parasite transmission in treescapes. Trees improve drainage and soil structure, potentially reducing parasite transmission; while shading and animal aggregation can increase parasite availability [6]. Net effects could be complex [7], and affect how best to plan and utilise trees on pasture. This component will measure parasites and their environmental correlates (nematode larval density around translocated dung; summer soil saturation for liver fluke