Fraser David
Animal Welfare Program, Faculty of Land and Food Systems and W. Maurice Young Centre for Applied Ethics, University of British Columbia, Vancouver V6T 1Z4, Canada.
Zoo Biol. 2009 Nov;28(6):507-18. doi: 10.1002/zoo.20253.
Attempts to improve animal welfare have commonly centered around three broad objectives: (1) to ensure good physical health and functioning of animals, (2) to minimize unpleasant "affective states" (pain, fear, etc.) and to allow animals normal pleasures, and (3) to allow animals to develop and live in ways that are natural for the species. Each of these objectives has given rise to scientific approaches for assessing animal welfare. An emphasis on health and functioning has led to assessment methods based on rates of disease, injury, mortality, and reproductive success. An emphasis on affective states has led to assessment methods based on indicators of pain, fear, distress, frustration and similar experiences. An emphasis on natural living has led to research on the natural behavior of animals and on the strength of animals' motivation to perform different elements of their behavior. All three approaches have yielded practical ways to improve animal welfare, and the three objectives are often correlated. However, under captive conditions, where the evolved adaptations of animals may not match the challenges of their current circumstances, the single-minded pursuit of any one criterion may lead to poor welfare as judged by the others. Furthermore, the three objectives arise from different philosophical views about what constitutes a good life-an area of disagreement that is deeply embedded in Western culture and that is not resolved by scientific research. If efforts to improve animal welfare are to achieve widespread acceptance, they need to strike a balance among the different animal welfare objectives.
（1）确保动物身体健康且机能正常；（2）尽量减少不愉快的“情感状态”（疼痛、恐惧等），并让动物享受正常的愉悦；（3）让动物以该物种自然的方式成长和生活。这些目标中的每一个都催生了评估动物福利的科学方法。对健康和机能的重视催生了基于疾病、损伤、死亡率和繁殖成功率的评估方法。对情感状态的重视催生了基于疼痛、恐惧、痛苦、挫折及类似体验指标的评估方法。对自然生活的重视引发了对动物自然行为以及动物执行其行为不同要素的动机强度的研究。这三种方法都产生了改善动物福利的实用途径，而且这三个目标往往相互关联。然而，在圈养条件下，动物进化出的适应性可能与当前环境的挑战不匹配，此时，单纯追求任何一个标准可能会导致从其他标准判断来看的不良福利状况。此外，这三个目标源于关于什么构成美好生活的不同哲学观点——这是一个深深植根于西方文化且未被科学研究所解决的分歧领域。如果改善动物福利的努力要获得广泛认可，就需要在不同的动物福利目标之间取得平衡。
