Assessing the welfare of growing dairy calves

本建议的目标是回答下列广泛的问题：个体小牛在运动游戏和社交游戏发生方面的差异是否反映了由于疾病、低能量摄入和/或生长不良造成的福利差异？2. 我们如何才能最好地测量运动和社会玩耍行为来评估奶牛的福利？3. 犊牛达到某些行为发展阶段的年龄（例如，由社交游戏取代运动游戏、首次发情行为、进食固体饲料的能力）是否可以用来评估成长期动物的福利？公众对农场动物福利的关注已导致农场动物的福利标准，而自动监测行为有可能使行为措施用于动物福利评估。奶牛犊牛福利状况不佳对成年奶牛的生产寿命有长期影响，因此建立良好的犊牛福利评估方法十分重要。在福利评估中使用的大多数措施确定了较差的福利，但对使用良好福利措施的兴趣越来越大。在生长中的动物中，玩耍行为被认为是一种积极的福利指标。奶牛小牛表现出各种各样的运动和社交游戏，但我们需要更好的证据来证明游戏与动物福利之间的联系。大多数评估生长中的动物福利的方案都是基于它们在特定年龄时的状态。然而，生长中的动物的福利可能会根据它们的发育情况得到更好的评估。这项拟议的研究包括一系列实验，用自动喂养系统饲养的奶牛群居，以验证社会和运动游戏的测量方法作为奶牛良好福利的潜在行为基础指标的使用。各种游戏行为发生的时间、吃固体饲料的能力和第一次发情的时间之间的联系将表明，行为发展的一般时间是相互关联的，并受到喂养和断奶策略的影响。与生殖发育较晚的年龄的联系可能有助于我们理解牛繁殖延迟的问题。

The objectives of this proposal are to answer the following broad questions:1. Do variations between individual calves in the occurrence of locomotor play and social play reflect variations in welfare due to illness, low energy intakes and/or poor growth? 2. How can we best measure locomotor and social play behaviour to assess the welfare of dairy calves? 3. Can the age at which calves reach certain stages in behavioural development (e.g. replacement of locomotor play by social play, first estrous behaviours, ability to eat solid feeds) be used to assess the welfare of growing animals? Public concern about farm animal welfare has led to welfare standards for farm animals and automated monitoring of behaviour has potential to enable behavioural measures to be used in animal welfare assessments. Poor dairy calf welfare has long term impacts on the productive life of adult cow, so it is important to have good methods to assess their welfare. Most measures used in welfare assessment identify poor welfare, but there is increased interest in using measures of good welfare. Among growing animals, play behaviour has been proposed as a good candidate for a positive welfare indicator. Dairy calves show a variety of locomotor and social play but we need better evidence of the link between play and animal welfare. Most schemes for assessing the welfare of growing animals are based on their state at a particular age. However, it is likely that the welfare of growing animals may be better assessed in terms of how they are developing. This proposed research involves a series of experiments on group housed dairy calves fed by automated feeding systems, to validate the use of measures of social and locomotor play as potential behavioural-based indicators of the good welfare of dairy calves. The link between the timing of the occurrence of various play behaviours, of the ability to eat solid feed and of first estrous will show the extent that the general timing of behavioural development is inter-related and affected by feeding and weaning strategies. The link with the age of later reproductive development may help us understand the problem of delayed reproduction of cattle.