Attention Bias Test Measures Negative But Not Positive Affect in Sheep: A Replication Study

Looking out for danger: Theoretical and empirical issues in translating human attention bias tasks to assess animal affective states

Understanding animal emotional (affective) state is highly relevant to various disciplines (e.g., animal welfare, neuroscience, comparative psychology), and has been significantly advanced by translating affect-induced cognitive bias paradigms rooted in human psychology to non-human animal studies. Attention bias (i.e., preferential attention allocation, AB) tests are increasingly used as more practical substitutes to commonly used judgement bias tests. Yet, evidence that AB reflects affective valence in animals is still limited. We review in-depth the concept of attention and AB described in humans and discuss utilising human-derived AB paradigms for measuring animal affective states. We describe key concepts and functions of attention in humans, before concentrating on the relationship between AB to threat detection and human anxiety. We critically review animal AB studies, discuss methodological discrepancies in such studies, and highlight the need for further experimental refinements. This includes identifying appropriate species-specific test designs and stimuli, modes of presentation (e.g., real-life vs. artificial stimuli), and consideration of subject-related factors (e.g., personality, age). We conclude that experimental limitations currently hamper the validity of AB as a proxy of animal affect and hope that the knowledge gaps highlighted in our review will encourage further research.

Do cows see the forest or the trees? A preliminary investigation of attentional scope as a potential indicator of emotional state in dairy cows housed with their calves

A positive mood in humans tends to broaden attentional scope while negative mood narrows it. A similar effect may be present in non-human animals; therefore, attentional scope may be a novel method to assess emotional states in livestock. In this proof-of-concept exploratory study, we examined the attentional scope of dairy cows housed with their calves either full-time, part-time (during daytime only), or with no calf contact (enrolled n = 10 each). Housing conditions were previously verified to induce differences in positive and negative emotional state, where part-time was considered more negative. Cows were trained to approach or avoid hierarchical images on a screen that were consistent in local and global elements (i.e., 13 small circles or crosses arranged in an overall circle or cross). After discrimination learning (>80% correct, over two consecutive days), 14 cows proceeded to test (n = 6 each full-and part-time; n = 2 no-contact, not analyzed). Test images showed inconsistent combinations of global and local elements (i.e., the overall global shape differs from the smaller local elements, such as a global circle composed of smaller local crosses and vice versa). Over two test days, approach responses to global and local images (each presented four times) were recorded. All cows were more likely to approach the local than the global image, especially part-time cows who never approached the global image; this may reflect a narrowed attentional scope in these cows. Full-time cows approached images more often than part-time cows, but overall response rates to global and local images were low, making specific conclusions regarding attentional scope difficult. Different housing conditions have potential to affect attentional scope, and possibly emotional state, of dairy cows, but statistical comparison to no-contact treatment was not possible. Cortisol concentration did not affect responses to images; thus arousal due to treatment or test conditions could not explain test performance. Further work with refined methodology and a larger sample size is required to validate the reliability of attentional scope as an assessment method of emotional state in cattle. Beyond this, the attentional scope test revealed how cattle may process, learn and respond to different visual hierarchical images, which further our understanding of cognitive and visual processes in cattle.

Sex impacts pain behaviour but not emotional reactivity of lambs following ring tail docking

Studies in humans have shown sex differences in response to painful events, however, little is known in relation to sex differences in sheep. Understanding sex differences would enable improved experimental design and interpretation of studies of painful procedures in sheep. To examine sex differences in response to pain, 80 lambs were tested across five cohorts of 16. The lambs were penned in groups containing two male and two female lambs with their respective mothers. Lambs were randomly allocated from within each block to one of four treatment groups; FRing–Female lamb, ring tail docked without analgesia, MRing–Male lamb, ring tail docked without analgesia, FSham–Female lamb, tail manipulated and MSham–Male lamb, tail manipulated. Following treatment, lambs were returned to their pen and were video recorded for 45 mins for behavioural observations of acute pain and posture. An hour after treatment, lambs then underwent an emotional reactivity test that consisted of three phases: Isolation, Novelty and Startle. Following treatment, Ring lambs displayed more abnormal postures (mean = 2.5 ± 0.5) compared to Sham lambs (mean = 0.05 ± 0.4, P = 0.0001). There was an effect of sex on the display of acute pain-related behaviours in lambs that were tail docked (P < 0.001), with female lambs displaying more acute behaviours (mean count = +2.2). This difference in behaviour between sexes was not observed in Sham lambs. There was no effect of sex on display of postures related to pain (P = 0.99). During the Novelty and Startle phase of the emotional reactivity test, Ring lambs tended to (P = 0.084) or did (P = 0.018) show more fear related behaviours, respectively. However, no effect of sex was observed. The results of this study indicate that a pain state may alter the emotional response of lambs to novel objects and potential fearful situations. It was also demonstrated that female lambs display increased sensitivity to the acute pain caused by tail docking compared to males.

Positive Aspects of Welfare in Sheep: Current Debates and Future Opportunities

The concept of positive welfare is an expansion of the traditional understanding that animal welfare is defined by minimizing stress, pain, suffering, and disease. Positive welfare shifts the animal welfare narrative from a focus on reducing negative experiences to proactively providing animals with opportunities to have positive experiences and feelings. The concept, although around for several decades, is in its infancy in terms of developing ways of assessing positive welfare on farms, especially in extensive systems, and there are challenges in the adoption of positive welfare practices and the monitoring of continuous improvement at the farm level. Using an iterative approach, this critical review aims to explore the extent to which positive welfare interventions and indicators are positioned and have been developed within the animal welfare literature for sheep. This paper critiques existing positive welfare indicators, such as choices in food and the physical environment, conspecific social synchronization, maternal bonds, intergenerational knowledge transfer, positive human-animal relationships, etc., as currently assessed by the 'good life framework'. It also reviews the characteristics of scientific measures for (positive) affective states in the current sheep literature and their potential contribution to understanding positive welfare states in sheep. In conclusion, this paper provides recommendations for future research regarding sheep welfare.

Positive Welfare Indicators in Dairy Animals

Nowadays, there is growing interest in positive animal welfare not only from the view of scientists but also from that of society. The consumer demands more sustainable livestock production, and animal welfare is an essential part of sustainability, so there is interest in incorporating positive welfare indicators into welfare assessment schemes and legislation. The aim of this review is to cite all the positive welfare indicators that have been proposed for dairy animals in theory or practice. In total, twenty-four indicators were retrieved. The most promising are exploration, access to pasture, comfort and resting, feeding, and behavioral synchronicity. Qualitative behavioral assessment (QBA), social affiliative behaviors, play, maternal care, ear postures, vocalizations, visible eye white, nasal temperature, anticipation, cognitive bias, laterality, and oxytocin have been also studied in dairy ruminants. QBA is the indicator that is most often used for the on-farm welfare assessment. Among all dairy animals, studies have been performed mostly on cattle, followed by sheep and goats, and finally buffaloes. The research on camel welfare is limited. Therefore, there is a need for further research and official assessment protocols for buffaloes and especially camels.

Housing and personality effects on judgement and attention biases in dairy cows

Affective states can be inferred from responses to ambiguous and threatening stimuli, using Judgement Bias Tasks (JBTs) and Attention Bias Tasks (ABTs). We investigated the separate and interactive effects of personality and housing conditions on dairy cattle affective states. We assessed personality in 48 heifers using Open-Field, Novel-Object and Runway tests. Personality effects on responses to the JBT and to the ABT were examined when heifers were housed under reference conditions. Heifers were subsequently housed under positive or negative conditions, and housing effects on animal responses in both tasks were investigated while controlling for personality. A Principal Component Analysis revealed three personality traits labelled Activity, Fearfulness and Sociability. Under reference conditions, personality influenced heifers' responses to the JBT and to the ABT, therefore questioning the tasks' generalizability across individuals. Against expectations, housing did not influence responses to the  JBT and heifers in the negative conditions looked at the threat later than heifers in the positive or reference conditions. More research is warranted to confirm the validity and the repeatability of the JBT and of the ABT as appropriate measures of affective states in dairy cows.

Towards a Positive Welfare Protocol for Cattle: A Critical Review of Indicators and Suggestion of How We Might Proceed

Current animal welfare protocols focus on demonstrating the absence (or at least low levels) of indicators of poor welfare, potentially creating a mismatch between what is expected by society (an assurance of good animal welfare) and what is actually being delivered (an assurance of the absence of welfare problems). This paper explores how far we have come, and what work still needs to be done, if we are to develop a protocol for use on commercial dairy farms where the aim is to demonstrate the presence of positive welfare. Following conceptual considerations around a perceived “ideal” protocol, we propose that a future protocol should be constructed (i) of animal-based measures, (ii) of indicators of affective state, and (iii) be structured according to indicators of short-term emotion, medium-term moods and long-term cumulative assessment of negative and positive experiences of an animal's life until now (in contrast to the current focus on indicators that represent different domains/criteria of welfare). These three conditions imposed the overall structure within which we selected our indicators. The paper includes a critical review of the literature on potential indicators of positive affective states in cattle. Based on evidence about the validity and reliability of the different indicators, we select ear position, play, allogrooming, brush use and QBA as candidate indicators that we suggest could form a prototype positive welfare protocol. We emphasise that this prototype protocol has not been tested in practice and so it is perhaps not the protocol itself that is the main outcome of this paper, but the process of trying to develop it. In a final section of this paper, we reflect on some of the lessons learnt from this exercise and speculate on future perspectives. For example, while we consider we have moved towards a prototype positive welfare protocol for short-term affective states, future research energy should be directed towards valid indicators for the medium and long-term.

A Multi-Disciplinary Approach to Assess the Welfare Impacts of a New Virtual Fencing Technology

Virtual fencing involving the application of audio cues and electrical stimuli is being commercially developed for cattle. Virtual fencing has the potential to improve productivity through optimized pasture management and utilization by grazing animals. The application of virtual fencing initiates public concern for the potential welfare impacts on animals due the aversive nature of using an electrical stimulus. It is therefore important to provide welfare assurance of the impacts of virtual fencing on livestock. In this paper, we provide an overview of the welfare assessment and validation stages for virtual fencing which could be applied to other new technologies utilizing novel systems. An understanding of stress measures and their suitability for use in specific contexts is discussed, including the use of glucocorticoids to measure both acute and chronic stress, and behavioral responses and patterns to indicate welfare states. The importance of individual differences in relation to learning and cognition are also highlighted. Together, this multi-disciplinary approach to welfare assessment provides a tool kit that may be applied for welfare assurance of some new technologies and systems for farm animals.