The point of the Piglet Scream Test is to identify those sows that increase the survival of their piglets through good maternal behaviour. For this to work, sows must be shown to differ in their test responsiveness, for differences to be consistent across parities and for responsiveness to be associated with piglet survival. Our data provide some first evidence that outdoor sows, kept under commercial production conditions, differ consistently from each other in their test responsiveness across parities. However, there was no evidence that this was associated with the survival of their litters. This, together with the lack of consistent evidence from other studies for a relationship between Piglet Scream Test responsiveness and piglet survival and concerns about its possible causes, cautions against the use of the test to enhance piglet survival on farms without further study. The paper highlights lack of standardisation of the test and pseudoreplication as concerns.

The assumption that animals are conscious and capable of experiencing negative sensations and emotions is at the core of most people's concerns about animal welfare. Investigation of this central assumption should be one goal of animal welfare science. We argue that theory and techniques from cognitive science offer promising ways forward. Evidence for the existence of conscious and non-conscious cognitive processing in humans has inspired scientists to search for comparable processes in animals. In studies of metacognition and blindsight, some species show behaviour that has functional parallels with human conscious cognitive processing. Although unable to definitively answer the question of whether the animals are conscious, these studies provide fresh insights, and some could be adapted for domestic animals. They mark a departure from the search for cognitive complexity as an indicator of consciousness, which is based on questionable assumptions linking the two. Accurate assessment of animal emotion is crucial in animal welfare research, and cognitive science offers novel approaches that address some limitations of current measures. Knowledge of the relationship between cognition and emotion in humans generates a priori frameworks for interpreting traditional physiological and behavioural indicators of animal emotion, and provides new measures (eg cognitive bias) that gauge positive as well as negative emotions. Conditioning paradigms can be used to enable animals to indicate their emotional state through operant responses. Although evidence for animal consciousness and emotion will necessarily be indirect, insights from cognitive science promise further advances in our understanding of this fundamentally important area in animal welfare science.

Retrieved memories of emotionally laden events are likely to influence the ongoing emotional state and behaviour of animals. If animals consciously experience memories and/or associated emotions, then recall of aversive or pleasurable events will affect their welfare. Even if they do not, retrieval of these (non-conscious/implicit) memories may result in behaviour, such as attempts to escape, that could lead to injury and damage. There is growing evidence that emotionally laden events are more readily stored in memory than neutral ones, and that the neurophysiological basis of this, involving acute elevations of the classic stress hormones and the action of the amygdala, is similar in humans and other vertebrate species. Thus, in humans and animals, emotional memories are likely to be stored as priority information and may readily be retrieved in the presence of relevant cues. If so, an important practical goal is to minimize the chances of negative emotional memories being cued inappropriately, especially for animals in captivity. Disruption of memory formation and retrieval is also important in an animal welfare context. Chronic or very high elevations of stress hormones appear to have both short- and long-term effects on brain structure and function that can interfere with efficient storage of information. Environmental disturbances, including common husbandry procedures, can also disrupt memory formation through retroactive interference effects. Elevated stress levels may both increase the chances of retrieval of negative information while hampering the retrieval of positive or neutral information. These effects may lead to poor learning abilities, selective or disrupted memory retrieval, and consequent inappropriate behaviour with adverse welfare consequences. If we understand them, we may be able to recommend housing or husbandry procedures that minimize the likelihood of their occurrence.

The stressful effects that environments have on farm and laboratory animal welfare are likely to depend on how much animals understand of the behaviour and intentions of their conspecifics as well as on their understanding of their physical environment. However, studies on animal social cognition have primarily focused on primates. Here, we report on our work on social cognition in domestic pigs. It focuses on the ability of domestic pigs to assess and use to their advantage the behaviour of conspecifics, and uses approaches pioneered in studies on primates. Our work has shown that dominant pigs use the privileged knowledge of a subordinate to their own advantage in a competitive foraging situation. While such exploitative behaviour is likely to be based on rapid learning about the subordinate ‘s behaviour, it is also possible that ‘higher’ cognitive abilities such as visual perspective taking could be involved. Ongoing work uses an adaptation of the Guesser-Knower paradigm to test whether pigs are indeed capable of visual perspective taking.

A key question in the management of group-housed captive animals is how long can an individual be removed from a social group and still be reintroduced with minimal social upheaval. In order to answer this question we require a knowledge of how long cage-mates, following a specified period of group-housing, can remember one another after separation. This issue was investigated in laboratory rats (Rattus norvegicus). Rats were group-housed for 18 days before being housed individually. One hour, 48 hr, and 96 hr after separation, they were exposed simultaneously to odour cues originating from unfamiliar rats and from former cage-mates. The rats spent significantly more time investigating the unfamiliar odour 1 hr and 48 hr, but not 96 hr, after separation, suggesting that, after 18 days of group-housing, juvenile rats remember former cage-mates for between 48 and 96 hr. The implications of this result for animal welfare are discussed.

In humans, excessive pessimism is strongly indicative of a depressive mental state. The negative outlook demonstrated by the depressed person is seen as the result of the depression in some way biasing the person's thinking in a negative direction (Beck 1967). This negative thinking is most clearly manifested as biases in attention to, and memory for, negative information (Gotlib & Krasnoperova 1998). Conversely, an individual in an elated, positive mood is likely to perceive and recall information in a more ‘optimistic’ manner and be less prone to focusing on negative stimuli. Here we have a situation where an emotional state (positive or negative affect) and a cognitive state (a bias for mood-congruent information) appear closely linked. Assuming a similar link in animals, we are trying to use operant training techniques to derive systematic tests of cognitive bias which may reveal subjective emotional states which are, themselves, very difficult to measure directly. The rationale behind the technique is to train animals to expect positive or negative outcomes to two training tones of differing frequency. Rats were trained on a go, no-go task where one tone signalled pending reward and the animals were required to make an operant lever press in order to receive it, and the other tone signalled a short, unavoidable period of white noise which the animals quickly stopped responding to. Thus, animals were trained to signal what they ‘expected’ to happen given a particular predictive cue. According to cognitive theories of depression, a depressed individual should show a greater level of expectancy of negative events, especially when presented with ambiguous stimuli, ie they should act pessimistically. Positive mood is associated with positive expectations, thus we would expect an individual in such a mood state to evaluate an ambiguous situation in a more optimistic way. We presented our trained animals with novel tones and recorded their responses before and after a period of housing in an ‘enriched’ environment which is often assumed to be a positive treatment for animals.

Development of the technique and preliminary results were presented.

We assessed the value of sleep behaviour as a novel measure of stress in group-housed animals. We observed, non-invasively, sleep behaviour in 144 group-housed rats, and related it to other physiological and physical indicators of stress and welfare. Sleep frequency and duration correlated negatively with adrenal weight, and positively with bodyweight gain, and final bodyweight. Thus, low frequencies of sleep behaviour and low sleep duration correlate with some indicators of elevated physiological and physical stress, raising the possibility that sleep behaviour may provide an under-utilised, but potentially important, non-invasive indicator of stress and welfare for animals in groups.

Elements of husbandry procedures, such as handling, may disrupt rodent social behaviour. Such effects may be contingent upon the familiarity between individuals and upon the quality and quantity of the disruption. We investigated this issue using laboratory rats. We placed 36 rats into groups of three. At the point of group formation, and at 24 h, 7 days and two weeks afterwards, individuals received one of three treatments: ‘handling’, exposure to novel conspecific ‘urine’, or ‘control’ (undisturbed), for a duration of either 5 or 15 mins. We used a social recognition test to measure the ability of the rats to recognise the urine of group members of increasing familiarity following the implementation of these treatments. The ‘control’ treatment did not appear to disrupt social recognition. The 5 min ‘urine’ treatment appeared to disrupt recognition only when the rats had received the briefest experience of the ‘familiar’ urine (5 mins). The 5 min ‘handling’ treatment, however, appeared far more disruptive, with an apparent disruption of social recognition even when familiarity with the urine donor was high (eg 7 days of group housing). Both the ‘handling’ and ‘urine’ treatments appeared more disruptive when presented for an increased duration (15 mins). There was also some evidence that increased experience of the handling procedure might reduce its disruptive effect. The results of this study have several implications for the welfare of laboratory-housed rats, and these are discussed.

Reporting of outcome variables by caregivers in welfare studies is commonplace but is open to subjective bias and so requires validation. Biases can occur in either direction: familiarity with an animal allows a deeper insight into welfare problems, but also can lead to reticence in admitting that an animal in one's care is experiencing problems. Here, we aim to validate owner-reporting of plumage condition of pet parrots, including those with self-inflicted feather-damaging behaviour (FDB), by comparing owners’ scores of feather condition with those of two independent raters, blind to the owners’ and each other's assessments. We surveyed pet parrot owners to collect data on basic demographics and feather condition, and requested four standardised photographs of birds. We received 259 responses (17% of the 1,521 people contacted); 78 sets of images of appropriate quality for assessment by raters were provided. Mean percentage agreement between owners’ and raters’ scores was mostly fair to substantial using Cohen's kappa; however, raters scored a greater proportion of feather damage than did owners. Overall, our results indicate owner-reporting of feather condition, including FDB, to be generally reliable and consistent with independent assessment of photographs. As the use of photographs can be limited by image quality, a failure to represent the long-term state of a parrot, and the potential for incorrect recording if assessed without relevant information (eg on moulting), this evidence that owner-reports can be reliable opens the door for larger-scale surveys of the extent of welfare-relevant problems.

Conventional longitudinal behavioral genetic models estimate the relative contribution of genetic and environmental factors to stability and change of traits and behaviors. Longitudinal models rarely explain the processes that generate observed differences between genetically and socially related individuals. We propose that exchanges between individuals and their environments (i.e., phenotype–environment effects) can explain the emergence of observed differences over time. Phenotype–environment models, however, would require violation of the independence assumption of standard behavioral genetic models; that is, uncorrelated genetic and environmental factors. We review how specification of phenotype–environment effects contributes to understanding observed changes in genetic variability over time and longitudinal correlations among nonshared environmental factors. We then provide an example using 30 days of positive and negative affect scores from an all-female sample of twins. Results demonstrate that the phenotype–environment effects explain how heritability estimates fluctuate as well as how nonshared environmental factors persist over time. We discuss possible mechanisms underlying change in gene–environment correlation over time, the advantages and challenges of including gene–environment correlation in longitudinal twin models, and recommendations for future research.

Manufacturing companies nowadays face growing numbers of heterogeneous customer requirements. Due to that, internal and external complexity lead to an increase in the associated costs. Especially companies with a high Engineer-to-Order business are strongly affected. To reduce external and internal complexity, Starting Solutions are a suitable way to do that. Starting Solutions require on the one hand the evaluation of product flexibility, on the other hand the evaluation of customer requirements. These two requirements are compared to each other and Starting Solutions are thereby derived.

Complex products and shorter development cycles lead to an increasing number of engineering changes. In order to be able to process these changes more effectively and efficiently, this paper develops a description model as a first step towards a data driven approach of processing engineering change requests. The description model is systematically derived from literature using text mining and natural language processing techniques. An example of the application is given by an automated classification based on similarity calculations between new and historic engineering change requests.

Mixing of commercial pigs frequently leads to intense aggression. Considerable phenotypic variation exists between individuals and selection against aggressiveness may offer a long-term reduction in aggression without incurring additional costs to the primary producer. The genetic contribution to aggressiveness was quantified in this study using the number of skin lesions as an indicator of involvement in aggression. A sample of 1132 pigs were mixed at an average weight of 27·9 (s.d. 4·6) kg into 96 pens on a commercial sire line nucleus unit. Post-mixing aggressiveness of pigs was assessed using the lesion score (LS) approach. Growth rate, between 27·9 and 91·9 kg, and backfat depth at 91·9 kg were recorded for a subsample of 658 pigs. With a pedigree file of 1947 animals, a heritability of 0·22 was estimated for the LS trait. No significant genetic or phenotypic correlations were found between LS and growth rate or backfat depth, but standard errors of estimates were large. The response to selection, when all selection pressure was placed on the LS trait, was a 25% reduction in LS per generation. It is therefore technically possible to select for a reduced LS without substantially inhibiting genetic progress in growth rate or backfat depth through antagonistic genetic relationships.

Qualitative assessment of behaviour is based upon the integration by the observer of many pieces of information which in conventional quantitative approaches are recorded separately. Behaviour is for example summed up as ‘fearful’, ‘anxious’ or ‘distressed’. Such interpretations form the core of the lay public's concern for animal suffering, and therefore are frequently dismissed as ‘anthropomorphic’ and unscientific. However, in theory it is possible that such assessments reflect observable aspects of behavioural organization, and may be liable to scientific analysis. A first step in considering this hypothesis is to investigate the interobserver reliability of qualitative assessments. The aim of this study was to determine the extent to which untrained observers show agreement in their spontaneous qualitative descriptions of interactive behaviour in growing pigs.

The concept of ‘coping strategies’ has received increasing attention over the last few years. Benus et al. (1991) reported two major types of strategy in rodents. These were the so-called active and passive strategies. The active strategy consists of being aggressive, forming behavioural routines and showing low responsiveness to changes in the environment, the passive strategy involves being low aggressive, flexible and responsive to changes in the environment. Hessing et al. (1993) reported similar findings in pigs. These strategies have potential implications for pig husbandry, since they may be more or less adaptive in specific farming environments.

From an animal production and welfare perspective, an important social choice made by farm animals is whether and how vigorously to fight others. The choice to fight (i.e. simultaneous escalated aggression by both contestants) may result in severe injury when unfamiliar animals first meet or compete for highly valued resources. Game theory models of aggressive interactions predict that animals have evolved to stop or avoid fighting when they assess their chances of winning a contest to be poor. Assessment may occur during or before a fight. If it occurs before a fight, reliable cues of fighting ability must exist. If farm animals can establish relative social status by assessment prior to fighting, it may be possible to construct social groups which contain individuals of differing abilities such that most disputes are resolved through assessment and levels of damaging aggression are kept low. Social status appears to be established by assessment rather than fighting in free-ranging deer and sheep when asymmetries exist in reliable cues of their fighting abilities such as roaring rate and horn size. However, there have been few detailed studies of other farmed species and findings are equivocal. Work on young pigs suggests that, in pair-wise encounters, individuals are unable to assess weight-related asymmetries in their abilities without fighting. However, recent studies of groups of pigs suggest that some form of assessment prior to fighting may occur. Individuals were classified as high (H) or low (L) aggressive on the basis of their behaviour in an attack latency test. When litters of H pigs were mixed with litters of L pigs, significantly fewer pairs of unfamiliar pigs fought than when newly mixed groups were made up of litters of H pigs only, or litters of L pigs only. Thus, fighting was least frequent when there was a marked asymmetry in the aggressiveness of unfamiliar individuals. Another study raised the possibility that H and L pigs may be following alternative strategies which, under certain circumstances, are similarly beneficial in welfare and production terms. Further work is required to substantiate these findings and to determine whether aggressiveness is a reliable cue of fighting ability and, if so, how it is manifest and assessed.

Choice tests, which measure animals' preferences for resources, are increasingly used to aid the design of new husbandry systems. However, under farm conditions, these systems are not always used as desired. A possible explanation for this is that laboratory testing and on-farm conditions induce different states of stress or disturbance in animals which, in turn, affect processes underlying their choice behaviour. One important process which underlies choice behaviour is spatial memory. To choose accurately, animals need to learn and remember the location of different resources. Studies of deer and cattle, which involve animals learning the location of different stimuli, have shown that some individuals are unable to learn to avoid apparently aversive restraining crushes (Pollard et al., 1994; Grandin et al., 1994), and that calmer individuals may make more accurate choices (Grandin et al., 1994).

Dominance hierarchies are commonly observed in groups of pigs (Beilharz & Cox 1967). These hierarchies appear to be established by individuals assessing each other's relative abilities, usually through fighting (Rushen & Pajor 1987). The resulting aggression is a well documented problem in pig husbandry. It could be reduced by mixing pigs who differ in certain respects, such that they rapidly form a hierarchy without vigorous fighting. Hessing et al. (1994) found that mixing pigs who showed high levels of resistance to being placed on their backs in a “back test” with pigs who were less resistant resulted in low levels of aggression. In this study we investigated whether mixing pigs which differ in their aggressiveness could reduce the negative effects of regrouping.

Twelve sows in good quality unstrawed stalls, three groups of five sows in strawed pens with individual feeding stalls and sows in a 38-sow group in a strawed yard with an electronic sow feeder were compared during the first four parities. They originated from the same source, were about 9 months of age and in the 7th week of their first pregnancy at the start of the experiment and were kept in adjacent rooms in a building, cared for by the same staff and given the same diets at a rate of 2·2 kg/day per animal. No new animals were added to the groups or stalls during the study and animals returned to the same condition after periods in farrowing and service accommodation. Using a wide range of welfare indicators, it was clear that stall-housed sows had more problems than group-housed sows and that tliese problems were worse in the fourth than in the first pregnancy. By the fourth pregnancy, stall-housed sows spent proportionately 0·14 of time showing activities which were clearly stereotypies and much time on activities which were sometimes stereotyped, i.e. ‘drinking’ and rooting or chewing at pen fittings making a total of proportionately 0·50 of time. Comparable figures for group-housed sows were much lower (0·037 and 0·081 in total). Stall-housed sows were also more aggressive than group-housed by the fourth pregnancy and their body weights were lower. There were no differences using physiological or immunological tests or measures of reproductive output. When the two group-housing systems were compared, sows in the electronic feeder system showed more fighting, especially soon after initial mixing, but fewer total agonistic interactions than sows in groups of five during the first pregnancy. Oral stereotypies were slightly higher in small groups, perhaps because of smaller pen space, than in larger groups but much lower than in stalls. By the fourth pregnancy there were few differences between sows in small and large groups and all seemed to have adapted well to the conditions. Evaluation of welfare in different housing systems requires use of a wide range of measures and of long-term studies.