Thermography as a tool for the assessment of stress and affective states in an avian model

动物福利是一个重要的问题，影响动物的健康，福祉和/或生产力在广泛的背景下，如农场，实验室和野生动物。有效和可靠的福利评估技术对于确定问题和在这一领域取得进展至关重要。目前的福利评估方法可能是耗时的，主要依赖于测量表明疼痛或痛苦的行为反应，如发声，或更微妙的变化，如抑制正常行为、行为改变或行为模式的变化。福利评估的生理方法也被使用，这些方法是基于通常在血液中测量的应激激素的释放。虽然这种方法已经建立，但它通常是侵入性的（需要血液样本），这些激素的循环水平可能受到许多生物因素的影响，而不是压力。也许最重要的是，迄今为止，基于激素的福利评估主要集中在消极状态的测量上，我们目前还没有一种测量方法可以可靠地区分积极和消极的精神或情绪状态。需要更可靠、侵入性更小或耗时更短的新技术。在压力事件中，身体的快速生理变化改变了血液流动的模式，将血液从动物的外围引导到身体的核心。这导致身体核心变暖和局部皮肤变冷，这些变化在急性（短期）压力和慢性（长期）压力下都会发生。热成像仪的最新进展为开发评估动物福利的远程方法提供了机会。热成像，也被称为红外热成像，通过测量动物发出的热辐射量来记录动物的表面温度。因此，表面温度是一种间接测量血流量的方法，有可能成为一种非侵入性的方法来评估对压力的生理反应，而不需要采血或探针连接。最重要的是，有证据表明，这种方法可能能够区分动物的消极和积极的精神状态。本研究项目的目的是验证红外热像仪作为一种新型的非侵入性工具的使用，以提供有关鸟类福利状况的相关和即时信息。我们将致力于家禽（蛋鸡），这是高度相关的物种，因为英国家禽业每年饲养数百万只家禽。商品家禽可能受到禁闭、跛行、饥饿、未确诊疾病或处理不当的影响，我们需要更好的方法来评估它们的福利。这项工作的具体目标是：1。通过比较表面温度对相同短期压力源的增加程度的反应，确定表面温度测量作为应力指标的准确性，并检查对不同类型压力源的反应。我们将验证这些信息与完善的福利措施，包括应激激素，核心体温和行为。2. 通过检查对长期压力情况的反应，并将其与无压力的鸟类进行比较，建立使用热成像作为慢性压力的指标。3. 检查体表温度模式在多大程度上与消极和积极的精神状态相关，以确定热成像是否可以成为一种区分良好和不良福利的新方法。这项工作将导致我们对鸟类对压力的热反应的理解取得重大进展。它将为福利评估开发适当的热成像方法，并确定这种技术在监测鸟类福利方面的商业应用潜力。

Animal welfare is an important issue influencing the health, wellbeing and/or productivity of animals in a wide range of contexts such as farm, laboratory and wild animals. Effective and reliable welfare assessment techniques are essential to identify issues and make progress in this area. Current approaches to welfare assessment may be time consuming and rely primarily on measuring behavioural responses that are indicative of pain or distress such as vocalisations or more subtle changes such as suppression of normal behaviour, redirection of behaviour or changes in behaviour patterns. Physiological approaches to welfare assessment have also been used and these are based on the release of stress hormones which are usually measured in the blood. While this approach is well established, it is usually invasive (requiring a blood sample) and circulating levels of these hormones may be influenced by many biological factors other than stress. Perhaps most importantly, hormone based welfare assessment has so far focused on the measurement of negative states, and we do not currently have a measurement approach that can reliably differentiate between positive and negative mental or emotional states. New techniques are required that are more reliable and less invasive or time-consuming. During stressful events, rapid physiological changes in the body alter the pattern of blood flow, directing blood away from the periphery of the animal to its body core. This leads to warming of the body core and localised cooling of the skin and these changes occur in response to both acute (short term) stress as well as chronic (longer term) stress.Recent advances in thermal imaging cameras provide an opportunity to develop remote methods of assessing the welfare of animals. Thermal imaging, otherwise known as infrared thermography, records the surface temperature of an animal by measuring the quantity of thermal radiation it emits. Surface temperature is therefore an indirect measurement of blood flow and has the potential to be a non invasive method of assessing physiological responses to stress without the need for blood sampling or probe attachment. Most importantly, there is evidence that this method may be able to distinguish between negative and positive mental states in animals.The aim of this research project is to validate the use of infrared thermography as a novel, non invasive tool to provide relevant and immediate information on welfare state in birds. We will work on the domestic fowl (laying hen) which is highly relevant species because millions of birds are reared annually in the UK poultry industry. Commercial poultry may be affected by confinement, lameness, hunger, undiagnosed disease or poor handling and we need better ways of assessing their welfare.The specific objectives of this work are to:1. Determine the accuracy of surface temperature measures as indicators of stress by comparing surface temperature in responses to increasing severities of the same short term stressor and also examine responses to different types of stressors. We will validate this information against well established welfare measures including stress hormones, core body temperature and behaviour. 2. Establish the use of thermography as an indicator of chronic stress by examining responses to long term stressful situations and comparing these to unstressed birds. 3. Examine the extent to which body surface temperature patterns are associated with negative and positive mental states, to determine if thermal imaging could be a novel way of distinguishing good and bad welfare. The work will lead to significant advances in our understanding of the thermal responses to stress in birds. It will develop appropriate thermographic approaches for welfare assessment and establish the potential for commercial application of this technique to monitor the welfare of birds.