Predicting and enhancing lifetime resilience in dairy cattle

动物的恢复力是指它们应对短期环境干扰并迅速恢复正常状态的能力，是公认的养殖牲畜的有益性状。适应力强的奶牛被认为具有完成多次泌乳的高概率，具有良好的繁殖性能，很少遇到容易克服的健康问题，并且在产奶量方面高效和一致。影响个体在其一生中健壮或有弹性的能力的一个主要因素是“健康和疾病的发育起源” （DOHaD），即在特定的发育敏感时间点对发育中的胚胎/胎儿的损害（例如营养损害、对疾病/毒素的炎症反应、治疗方法、激素浓度升高）可以改变个体对疾病的易感性。因此，奶牛个体和牛群的恢复能力对于优化健康、福利和生产力以及减少奶牛养殖的环境足迹至关重要，因为该行业的目标是实现净零排放。与根据个别疾病、特征或综合症来考虑健康或福利不同，增强的复原力使广泛增强健康和福祉成为可能。因此，提高抗灾能力可以逐步减少奶牛的地方病。这项为期12个月的研究的目的是量化子宫内环境因素对奶牛产后终身恢复能力的影响，使用非常大的数据集（300,000头奶牛终身记录）。我们对这项研究的假设是，在怀孕早期发育敏感阶段对奶牛的干扰会影响其后代的终身恢复能力。我们将使用包含后代详细终生记录的大型数据集来量化和预测复原力，这些数据集可以映射回后代在怀孕的特定阶段所经历的大量母亲介导的压力源。我们将在怀孕的特定阶段测量已知的农场压力源的影响，并评估这些压力源如何支撑终生恢复力。在12个月的项目中，我们将；1)根据奶牛在子宫内发生的事件，建立一个优化的、有效的预测模型。2)确定并量化妊娠期影响终生恢复力的主要因素和事件，从而评估通过优化畜群管理可以提高恢复力的程度。结果：i)由农民和兽医共同开发的一种预测奶牛出生时终生恢复力的方法，为农场的选择性育种计划提供信息。ii)确定怀孕期间影响后代终生适应力的主要因素（及其相对重要性），为优化农场适应力的管理策略提供信息。这将如何帮助农民？通过对奶牛出生时的终生适应能力的准确了解，农民将能够；1)避免从低恢复力的替代品中繁殖（有证据表明，子宫内的伤害可以通过遗传变化传播，从而产生跨代效应），ii)尽量减少怀孕期间对恢复力有有害影响的因素（通过整体群体恢复力评分来监测成功与否），iii)在短期内，对得分低的动物亚群采用改进的管理策略，以减轻其低恢复力。转化为农民：我们的行业合作伙伴已经开发了一个软件平台来容纳模型，实时构建弹性预测，并将结果直接交付给农民-因此，将研究成果转化为实践的途径已经到位。

Resilience in animals refers to their capacity to cope with short-term environmental disturbances, with a fast return to normal status and it is an acknowledged beneficial trait of farmed livestock. Resilient cows are considered those with a high probability of completing multiple lactations, with good reproductive performance, that encounter few health problems which they overcome easily, and that are efficient and consistent in their milk production. A major contributor to an individuals' ability to be robust or resilient over their life-course is the "Developmental Origins of Health and Disease" (DOHaD), whereby insults to the developing embryo/foetus (e.g. nutritional insults, inflammatory response to disease/toxins, therapeutics, elevated concentrations of hormones) at specific developmentally sensitive time points, can alter an individuals' susceptibility to disease. Resilience in dairy cattle at both individual and herd level is therefore considered critical to optimise health, welfare, and productivity and to reduce the environmental footprint of dairy farming as the industry targets net-zero. Rather than considering health or welfare according to individual diseases, traits or syndromes, enhanced resilience allows the possibility of a wide-ranging enhancement of health and wellbeing. Therefore, enhancing resilience could provide a step change to reduce endemic disease in dairy cows. The aim of this 12-month study is to quantify in-utero environmental factors that contribute to post-partum lifetime resilience in dairy cows, using a very large set of data (>30,000 cow lifetime records).Our hypothesis for the research is that perturbations to dairy cows during developmentally sensitive stages of early pregnancy influence lifetime resilience of their offspring. We will quantify and predict resilience using a large dataset containing detailed lifetime records for the offspring that can be mapped back to a wide of maternal-mediated stressors experienced by the offspring at specific stages of pregnancy. We will measure the effect of known on-farm stressors during specific stages of pregnancy and evaluate how these underpin lifetime resilience. During the 12 month project we will;1) Produce an optimised, validated predictive model of lifetime resilience for dairy cows from events that occur while in utero.2) Identify and quantify the major factors and events during pregnancy that impact on lifetime resilience and thereby evaluate the extent to which resilience can be enhanced through optimised herd management.Outcomes:i) A method to predict lifetime resilience for dairy cows at birth, co-developed by farmers and vets, to inform selective breeding programmes on-farm.ii) Identification of major factors during pregnancy (and their relative importance) that impact the lifetime resilience of the offspring to inform management strategies to optimise resilience on-farm. HOW WILL THIS HELP FARMERS? With an accurate knowledge of lifetime resilience for dairy heifers at birth, a farmer will be able to; i) avoid breeding from replacements with low resilience (evidence indicates that in utero insults can be transmitted via genetic changes, giving transgenerational effects), ii) minimise the factors during pregnancy that have a deleterious impact on resilience (success being monitored by an overall herd resilience score), iii) in the short term, use improved management strategies for the subset of animals with low scores, to mitigate their low resilience.Translation to farmer: Our industry partner has developed a software platform to house the models, construct the resilience predictions real time and deliver results direct to farmers - therefore the route to translate research findings to practice is already in place.