It is believed widely, and with good reason, that some other members of the animal kingdom, like us, have feelings (associated with brain states induced by various sensory inputs and cognitive processes) which can be pleasant or unpleasant. Associated with the strengthening scientific foundations for this belief, there has been growing consensus around the world that we have a moral responsibility, in all of our dealings and interactions with sentient animals, to take account of their feelings. This has led to widespread re-evaluation, in recent years, of the nature of our interactions with other animals. However, assessment of the feelings of animals — the quality of their lives — remains a great challenge for veterinarians and others involved with their management. The fundamental difficulty is that whilst judgements about management or treatment often have to be made on the basis of our inferences of how they feel (ie of the feelings they consciously experience), a subjective step cannot be avoided in making these inferences. We cannot know how other animals feel but can only infer this based on our knowledge of the animal and on our own experiences of feelings. This inevitable ‘gap’ in objective deductions about feelings is often wide enough that people can reach radically different conclusions when judging an animal's quality of life. Opinions thus often differ regarding the point at which it becomes kinder to euthanase an animal than not to do so, the point at which it becomes kinder not to undertake a potentially painful therapeutic intervention than to do so, and where the balance lies when animal welfare costs are being ‘weighed’ against some benefit of their use for humans (eg as laboratory, farm or companion animals). The aim of this meeting is to discuss if and how science has helped in developing reasoned approaches to these dilemmas, and to consider the need for further research, education, and policy development.

The dual problem of explaining brain evolution and the way in which it has led to wide species differences in behaviour and physiology has often appeared intractable to scientists. The main limiting factor is that we do not understand enough about how brains work to appreciate why gross or fine morphological differences can lead to the considerable across- as well as within-species differences in behaviour. Even at a molecular level, while two-thirds of our genes are involved in regulating brain function, there is a high degree of homology within different phyla. In the context of quality of life (QoL), arguably the most important consideration is that the brain you have evolved is adapted to the environment you are living in and is capable of generating ‘conscious’ experience. When that environment is radically altered, issues arise regarding whether there is sufficient adaptability to cope and the extent to which mental as well as physical suffering might be experienced as a consequence. At the other end of the spectrum there is the question of how enriched social and physical environments might enhance QoL through promoting positive affect. Here I will discuss potential functional contributions of differences in brain size and organisation and the impact of experience. I will mainly focus on mental functioning and show particularly that capacities for consciousness, emotional experience, social interaction and cognition and behavioural flexibility are likely to be widespread in other animal species, even if less developed than in humans.

Quality of life (QoL) is an abstract construct that has been formally recognised and widely used in human medicine. In recent years, QoL has received increasing attention in animal and veterinary sciences, and the measurement of QoL has been a focus of research in both the human and animal fields. Lord Kelvin said “When you cannot measure it, when you cannot express it in numbers — you have scarcely in your thoughts, advanced to a stage of science, whatever the matter may be” (Lord Kelvin 1893). So are we able to measure animal QoL? The psychometric measurement principles for abstract constructs such as human intelligence have been well rehearsed and researched. Application of traditional and newer psychometric approaches is becoming more widespread as a result of increasing human and animal welfare expectations which have brought a greater emphasis on the individual. In recent decades the field of human medicine has developed valid measures of experienced pain and QoL of individuals, including those who are not capable of self-report. More recently, researchers who are interested in the measurement of animal pain and QoL have begun to use similar methodologies. In this paper, we will consider these methodologies and the opportunities and difficulties they present.

The notion ‘quality of life’ (QoL) suggests that welfare in animals encompasses more than just an absence of suffering; it concerns the quality of an animal's entire relationship with its environment, of how it lives its life. Judgements of such quality are based on the integration of perceived details of how animals behave over time in different contexts. The scientific status of such judgements has long been ambiguous, but in recent decades has begun to be addressed by animal scientists. This paper starts with a brief review of qualitative approaches to the study of animal behaviour, which tend to address characteristics such as individuality, personality, and emotionality. The question then arises whether such characteristics involve a subjective, experiential aspect, and identify animals as sentient beings. The second half of this paper argues that taking the integrative nature of qualitative judgements seriously enables a ‘whole animal’ perspective, through which it becomes possible to view behaviour as a dynamic, expressive body language that provides a basis for assessing the quality of an animal's experience (eg contented, anxious). Judging this quality is a skill that requires knowledge of species-specific behaviour, experience in observing and interacting with animals in different contexts, and a willingness to communicate with animals as sentient beings. A substantial body of research indicates that this skill can function reliably in a scientific context, and can be applied usefully as a practical welfare assessment tool. Thus qualitative approaches to the study of animal behaviour should make an important contribution to the growing interest in animal QoL.

Improving the quality of life of captive animals is dependent on developing valid measures of how animals feel about their lives. It has recently been suggested that biases in information processing may offer a novel means of understanding animal emotions. Anxious and depressed people tend to interpret ambiguous information negatively. We explored the proposal that such cognitive biases also exist in non-human animals and could therefore be used as novel measures of animal welfare. We used a novel cognitive bias task based on a learnt taste aversion to determine whether birds deprived of environmental enrichment show biases in their classification of ambiguous signals. We hypothesised that starlings in enriched cages should be more likely to classify ambiguous signals as being associated with a positive outcome than starlings housed in standard, unenriched cages. Starlings were trained on a go/no-go procedure to discriminate between two visual stimuli (cardboard lids of white and dark grey) associated with outcomes of a different value (palatable and unpalatable mealworms hidden underneath). Individual birds' responses to unreinforced, intermediate stimuli (various shades of grey between white and dark grey) were subsequently examined while each bird was housed sequentially in both standard and enriched cages. The probability of a bird classifying an ambiguous pale grey lid as hiding a palatable mealworm was lower in standard cages than enriched cages, but this difference was found only in birds that received enriched cages first. Our results can be interpreted as showing a pessimistic bias in birds that have recently experienced a decline in environmental quality. These findings support the use of cognitive bias-based tasks as a novel, non-invasive technique for assessing welfare in non-human animals.

The concept of quality of life in animals is closely associated with the concepts of animal sentience and animal welfare. It reflects a positive approach that inquires what animals like or prefer doing. The assessment of farm animal welfare requires a good understanding of the animals' affective experience, including their emotions. However, affective experience in animals is difficult to measure because of the absence of verbal communication. Recent studies in the field of cognitive psychology have shown that affective experience can be investigated without using verbal communication by examination of the interactions between emotions and cognition. On the one hand, appraisal theories provide a conceptual framework which suggests that emotions in humans are triggered by a cognitive process whereby the situation is evaluated on a limited number of elementary criteria such as familiarity and predictability. We have applied these appraisal theories to develop an experimental approach for studying the elementary criteria used by farm animals to evaluate their environment and the combinations of those criteria that trigger emotions. On the other hand, an increasing body of research, first in humans and then in other animals, suggests that emotions also influence cognitive processes by modifying attention, memory and judgement in a short- or long-term manner. Cognitive processes could therefore be manipulated and measured to provide new insights into how not only emotions but also more persistent affective states can be assessed in animals. Further work based on these cognitive approaches will offer new paradigms for improving our understanding of animal welfare, thus contributing to ‘a life of high quality’ in animals.

Our view of which individuals should be the subjects of our moral actions is expanding to include more people and more species. Animal welfare is the subject of rapidly increasing concern in most countries in the world, and this concern is resulting in changes in the ways in which animal users keep and treat animals. Ethical decisions about whether the killing of an animal is justifiable should be considered separately from those about how poor welfare can be and still be acceptable. The term ‘euthanasia’ should be restricted to killing an animal for its own benefit. Quality of life (QoL) in humans is generally taken to include: physical condition and any impairment of this resulting from injury or disease; capacity to function; perception of functioning; and satisfaction with functioning in relation to what is believed possible. If the welfare of an individual is its state as regards its attempts to cope with its environment, then welfare is essentially the same as QoL. Both include the state of the individual's coping systems, including those responding to pathology, various behavioural and physiological responses, and cognitive processes associated with suffering or pleasure. Hence, both welfare and QoL include health and the extent of positive and negative feelings. Many papers referring to animal welfare include objective quantification whilst few papers referring to QoL do so. Some human studies assess QoL by the less objective method of questions asked of subjects. Neither QoL nor welfare should be assessed using solely subjective measures. Assessment of welfare must take account of the wide variety of coping systems and coping strategies used. A range of measures including those of behaviour, physiology, brain function, immune system function, and damage is needed. The ease or difficulty of coping should be interpreted within the framework of the abilities of the animal. Animals with more sophisticated cognitive functioning may have the best abilities to cope with problems. The scheme presented here for assessing welfare over time facilitates ethical decisions regarding whether welfare is good or whether it is unacceptably poor.

Although the term ‘quality of life’ (QoL) is not unfamiliar to veterinary surgeons, only recently has the scientific community attempted to measure it in farm and companion animals. Typically such studies have applied methodologies from the field of human health-related quality of life (HRQoL), without due consideration of the applicability of both the term and its measurement to animals. However, it is necessary to clarify the philosophical basis of QoL if it is to be defended as a rigorous and reliable aid to decision-making in animal welfare science. In this paper we review common concepts in human HRQoL and discuss the value of, and difficulties regarding, the transfer of the concept of human HRQoL to companion animals. Human definitions tend to focus on individuals and their assessment of the state of their life in terms of physical, social and psychological functioning. The use of the term ‘quality of life’ for animals may therefore expand on what is usually considered when using the term ‘welfare’, and thereby improve on current practice, which tends to focus on relatively few outcome measures that are largely indicative of poor welfare. However, failure in the human literature to properly define QoL and defend the choice of measures accordingly, together with the common use of objective indicators and proxies, has led to confusion over the relative roles of objective and subjective measures in the determination and constitution of QoL. A suggestion for an appropriate definition of animal QoL that clarifies these relationships is offered, together with a list of social/environmental and physical/psychological health-related domains that may be suitable for a generic companion animal QoL assessment tool. In the absence of knowledge on both basic needs and individual preferences, particularly for institutionalised animals, QoL tools may be more appropriately designed as outcome-based tools, focussing on observable signs of health and behaviour. The extent to which recent QoL assessment tools for companion animals have covered these domains, and the extent to which the psychometric properties of the tools have been addressed, is also briefly discussed.

There is an increasing requirement for tools to assess and improve animal welfare in an objective and scientifically based manner. In our research a concept of welfare is applied which states that welfare is determined by the balance between positive and negative experiences. This concept implies that an interaction exists between stress systems and reward systems in the brain and, as a consequence: (I) negative experiences induce an increased sensitivity (ie need) for positive experiences; and (II) negative experiences can be compensated for by positive experiences. On this basis, two uses of reward-related behaviour can be hypothesised: (I) reward sensitivity may be used as a tool to assess the state of an animal in terms of welfare because it can indicate the current state of the balance that is dependent on previous (stressful) experiences; and (II) regular presentation of rewards may serve as a tool to counteract stress by shifting the balance to the positive side and, thus, to improve welfare. In order to investigate this, we used the rat as a model. Reward sensitivity was determined by the spontaneous behavioural response shown during expectation of a reward (ie anticipatory behaviour). A third (III) use of reward-related behaviour derives from the fact that anticipatory behaviour is influenced by the (rewarding) properties of the forthcoming reward (or other event) and, thus, may serve as a tool to assess the animal's perception of this reward/event. This paper presents a descriptive overview of the evidence obtained thus far for the three proposed uses of reward-related behaviour. The biological background of our concept of welfare can be generalised to all (vertebrate) species, and anticipatory behaviour can be evoked in a wide range of other species. Therefore, this tool for measuring and improving the welfare of captive animals has great potential and will contribute to a good quality of life for captive animals.

In this paper I describe a hypothetical strategy for assessing poor and good welfare with the aim of making a judgement about an animal's quality of life. The concepts discussed here may also contribute to the notion of what makes ‘a life worth living’. The strategy involves attributing scores to positive and negative aspects of an animal's well-being, using predefined categories and a simple scoring rote, and then summating these scores into an overall welfare score. The strategy incorporates a mathematical calculation that has certain mathematical biases to help ensure that any animal suffering is not excessive. I draw attention to some limitations of the proposed strategy and stress that such mathematical scoring systems cannot be used simplistically. Nevertheless, the proposed strategy could be refined, tested and validated to assist decision-making by those with a duty of care to the animal concerned.

An international panel of experts in the fields of canine and feline health, welfare and behaviour conducted an online discussion addressing two questions: (1) how can one define quality of life (QoL) for dogs and cats in confined living situations, such as laboratories; and (2) what additional research is needed to determine how optimal QoL can be achieved? The panel suggested that QoL encompasses animal welfare and the subjective ‘feelings’ of the animal regarding its life, and that it can only be inferred from behavioural, physiological and other measures. Two methods for measuring QoL were proposed: establishing an ethogram defining QoL for individuals; and developing a ‘quality of living’ scale that can be applied to facilities housing groups of dogs and cats. Constructing these measures requires a comprehensive research program, and the paper discusses overall research objectives, specific questions that must be addressed, and some proposed research methods.

Two distinct approaches have emerged for the assessment of quality of life (QoL) and welfare in domestic dogs. One approach, which has so far been applied only to companion dogs, is derived from proxy assessment of QoL in human beings, with the owner or veterinarian acting as the proxy. Because dogs are a different species to human beings, assessment by proxy is even more challenging than when the subject being assessed is human. Our evaluation of published studies indicates that existing canine QoL instruments are imperfect, in part because of avoidable deficiencies such as failure to define QoL and using measures of health status as sole indicators of QoL. The second approach to QoL assessment, which stems from animal welfare science, is based upon objective measurement of behaviour and stress physiology, and has been applied mainly to dogs in laboratory and rescue kennels. We review these and our own recent studies, and conclude that although interpretation of signs of acute stress may be relatively straightforward, signs of chronic stress such as stereotypic behaviour require further research before they can be incorporated into QoL measures. So far, there has been little attempt to integrate proxy assessment with objective measures. We recommend that this integration would be beneficial. Fundamentally, both approaches aim to describe and quantify aspects of some inner state of well-being, and it should eventually be possible to map each on to the other.

The Glasgow Composite Measure Pain Scale (CMPS) for dogs suffering acute pain, developed using psychometric methodology, measures pain to a level of precision suitable for clinical trials. However, for routine clinical use, where the emphasis is on speed, ease of use, and guidance for analgesia provision, a short form (CMPS-SF) was developed. The CMPS-SF comprises six behavioural categories with associated descriptive expressions (items): vocalisation (4), attention to wound (5), mobility (5), response to touch (6), demeanour (5) and posture/activity (5). Items are placed in increasing order of pain intensity and numbered accordingly. The observer chooses that item within each category which best describes the dog's behaviour and ranked scores are summed; the maximum pain score is 24, or 20 if mobility is impossible to assess. Veterinary surgeons in Glasgow, University College Dublin and North Carolina Veterinary Schools completed the CMPS-SF for 122 dogs undergoing post-operative care and thereafter were asked “Do you think this animal requires analgesia? Yes/No”. The population difference in median pain score, for dogs considered to require analgesia (seven) compared with those that did not (three), was highly statistically significant (P < 0.001). Consideration of a clinical decision-point for analgesia gave an intervention level of 6/24, and 5/20 when section B (mobility assessment) could not be carried out. Difficulties in recognising pain contribute to the sub-optimal use of analgesics in veterinary practice. The CMPS-SF provides a practical means of assessing acute post-operative pain and provides guidance with regard to analgesic requirement, so improving pain management and welfare. The CMPS-SF can be downloaded from the Glasgow Pain and Welfare website at http://www.gla.ac.uk/vet/painandwelfare.

The aim of this preliminary study was to identify key behavioural indicators of pain in cats. The behaviour of cats before and after ovariohysterectomy was analysed using a detailed behavioural ethogram. A comparison of behaviours between cats given pre-operative analgesia only and cats given both pre- and post-operative analgesia indicated that both groups demonstrated changed behaviour following surgery, compared to a control group of cats which underwent anaesthesia but not surgery. However, some specific postures, such as ‘half-tucked-up’ and ‘crouching’, were identified that occurred with greater frequency in the cats receiving pre-operative analgesia only, as compared to those receiving additional post-operative analgesia. This indicates that there are some key behaviours that may be useful in determining pain in cats. Routine administration of pre- but not post-operative analgesia may be ineffective for adequately alleviating pain in cats.

In many situations choices must be made that will have an impact on the welfare of companion animals. Often one of the options will be to euthanase the animal in question. The way in which one views this option will depend not only on one's assessment of the quality of the animal's life (or the lives of other affected parties), but also on how one values an animal life as such. Clearly, a companion animal may be valued by a human being or by another animal. A dog's death may affect its owner's quality of life (QoL), or it may affect the QoL of other animals in the household. But does the life of an animal have any value other than that? Is anything lost, for example, when a dog that lived with a sole owner, now deceased, is euthanased? Conversely, would anything be gained if the dog were re-homed (apart from the potentially positive contribution to the new owners' QoL)? More generally, in prolonging, or refraining from ending, the life of an animal, is it thereby ensured that something of value persists? There seem to be three main views on this matter. The first is that animal life has no value in itself. The second is that animal life has value to the extent that the life in question is worth living for the animal. The third view is that the life of an animal has a value that exceeds what is ‘in it’ for the animal in question. The view one accepts here will have a dramatic impact on one's attitude to many of the choices to be made about the treatment of companion animals — choices in which one must balance quality of life against, as it were, quantity of life. So the heart of the matter is not only quality of life. It is also value of life. Unfortunately it may prove much more difficult to agree about the value of animal life than it is to agree about the significance of animal welfare.

A veterinary surgeon wishing to practice in the UK promises, on admission to the Royal College of Veterinary Surgeons, that their “constant endeavour will be to ensure the welfare of the animals committed to [their] care” (RCVS 2006 Guide to Professional Conduct). Yet a constant dilemma is that the veterinary surgeon deals with the animal's welfare differently depending on the category into which the particular animal fits at a particular time — even though its ability to suffer is the same whatever the circumstance. A laboratory animal is considered by many to suffer the most insults to welfare, yet its welfare is protected by a plethora of regulations, ethical reviews, best-practice guidelines and vociferous public opinion. While any decision on its treatment will take into account the scientific outcome, the judgement will have been considered by many and the outcome already decided. The companion animal may be much loved by its owner but its veterinary treatment will be affected by the psychological state of that owner and his/her ability to pay; the animal's treatment becomes a ‘family management’ issue. In veterinary treatment of a farm animal, the benchmark for ‘acceptable’ suffering can be quite different; lower levels of welfare may be tolerated over considerable periods. When a wild animal is presented for treatment, the welfare of the individual may not be best served by anything other than euthanasia, yet treatment is often enthusiastically attempted. We explore this inconsistency of approach to animal welfare, using examples, and we attempt to rationalise and raise awareness of the inconsistencies. We propose the use of a welfare illustrator grid to increase cross-sector objectivity and improve harmonisation of approach across the sectors.

Many breeds of companion animal have inherited disorders that may impair quality of life (QoL) to the extent that it is unkind to keep them alive. If we struggle to discern when this point is reached, why do we breed compromised, short-lived animals in the first place? If we struggle to judge when environmental conditions cause an unacceptable QoL, why not breed appropriately for modern environments? In breeding pedigree dogs, five major problems arise: (1) some breed standards and selection practices run counter to dog welfare; (2) insufficient selection pressure seems to be exerted on some traits that would improve animal well-being and produce dogs better suited to modern environments; (3) the incidence of certain inherited defects in some breeds is unacceptably high; (4) the dearth of registered animals of certain breeds in particular countries makes it extremely difficult for breeders to avoid mating close relatives; and (5) there may be financial disincentives for veterinarians to reduce the incidence of inherited diseases. Before we can judge when behavioural or morphological changes caused by selective breeding result in an unacceptable QoL, we have to know which are prevalent. This paper reviews progress in two Australian schemes to monitor trends in the prevalence of inherited disorders in dogs and to promote behavioural phenotypes likely to cope with contemporary domestic environments.

The effect of varied cultural traditions on concepts of animal welfare appears to be a novel issue, growing out of recent societal concerns with globalisation, multi-culturalism, and diversity. In more imperialistic times, Western culture cared little about such issues. Upon reflection, however, it is apparent that this is not a new issue, as even within our culture the concept of welfare has been variously defined, based on differences in values in general and ethics in particular, varying enormously with different views of the moral status of animals. A most dramatic example of this can be found in production agriculture's view that (to paraphrase) ‘the animal is experiencing good welfare when it fulfils the human (production) purpose for which it is kept’, as expressed in the Council for Agricultural Science and Technology (CAST) report of 1981. Clearly, an animal welfare advocate opposed to confinement agriculture would have expressed a very different view. If the concept of animal welfare is both intra- and cross-culturally varied, how then does one resolve differences? The answer may be found in what I have termed the ‘new social ethic for animals’ that is fairly uniform across Western societies, as I explain in this paper. In essence, the new ethic focusses on satisfying animals' needs dictated by their telos or biological nature. Insofar as Western democratic societies dictate to the rest of the world, which is economically dependent upon them, we will see this animal ethic achieve global hegemony, much as the notion of human rights has become globally ubiquitous as an ideal.

In animal care, when current decisions are made to maximise long-term quality of life (QoL), a key necessity is being able to make accurate predictions about how current choices will affect the animal's future QoL. However, in the procession of any individual's life, many factors that influence QoL change — some are foreseeable, many are not. Moreover, QoL has no fixed anchor points; it is dynamic, mutable, with a shifting frame of reference over time. In addition to actual changes in QoL over time, numerous factors have been identified that influence one's ability to adopt the mindset of the individual at a later point in time — for one's self as well as that of others. It has been shown that in people, across a wide range of health conditions, individuals with illness or disability typically report greater happiness and QoL than do healthy people envisioning themselves in similar circumstances (‘the disability paradox‘). Difficulties in QoL outcome prediction fall into two categories: (1) predictions made with the wrong mindset, in which there is a mismatch between the mindset of the assessor/predictor and that of the assessee/experiencer; and (2) predictions made on the basis of unforeseen or incorrectly estimated psychological changes in the assessee/experiencer.