Husbandry training and environmental enrichment are both important advancements associated with current behavioural welfare practices. Additionally, the use of training procedures has been proposed as a form of enrichment, with the implication that training can produce beneficial behavioural welfare results. This paper examines the concept of training as enrichment through three distinct ways training procedures could enrich: (i) training facilitates enrichment usage; (ii) training modifies interactions, conspecific or otherwise; and (iii) training expands behavioural repertoires. Within each category, the paper focuses on past research that provides empirical support for training functioning as enrichment, as well as related areas of research that provide additional evidence. Previous studies support the claim that training is enriching, with additional research necessary to better understand how prevalent and under what conditions training procedures function as enrichment. Future training research should examine these potential enrichment effects, including methodology that allows for comparisons to traditional enrichment, the use of welfare diversity/variability indices, and the effects of learning on trainers and trainees alike.

Evidence-based approaches are key to advancing all areas of zoo and aquarium practice. Output from empirical study must be disseminated to those within the industry so that results can support changes to husbandry and management for individual species. Information on enrichment techniques is published in a range of sources, including papers in the peer-reviewed and ‘grey literature’ (ie professional but non-reviewed publications). To investigate how evidence is implemented into enrichment practices, we sampled all enrichment studies identified in one online repository of peer-reviewed papers and two grey literature publications across an eleven-year period. We recorded whether the enrichment was supported with biological evidence (whether it was developed using published enrichment-focused research for that species and/or with the species’ ecology and behaviour information) alongside analysis of the type of enrichment used and the chosen study species. Enrichment articles were more likely to be supported by biological evidence in peer-reviewed than grey literature. Taxonomic differences in the use of evidence were noted; for example, enrichment provided to carnivores and parrots was more likely to be supported with biological evidence compared to that used for penguins. Of the five enrichment types, nutritional enrichment was most often based on biological evidence. Multi-category and physical enrichment types were more common across all literature sources whereas social enrichment was less common, suggesting barriers to implementation of all enrichment types in zoological facilities. Our research suggests that zoo and aquarium professionals are considering species-specific welfare needs by ensuring that enrichment protocols are supported by biological evidence. However, opportunities to diversify the enrichment types being offered and species being researched are identified.

Stress during handling can negatively impact the welfare of an animal. Gradual habituation or systematic desensitisation can reduce this but is not always possible. Blindfolding has been shown to decrease stress indicators, including heart rate and struggling in cattle (Bos taurus), but has not been studied in domestic rabbits (Oryctolagus cuniculus). We surveyed 49 wildlife rescues, rehabilitators and veterinarians, and found that blindfolding and swaddling are widely used and believed to reduce stress and struggling in rabbits. However, these methods may simply preclude escape and result in sensitisation over repeated exposure. We next conducted a controlled trial investigating the effects of blindfolding and swaddling repeatedly over five days on behavioural and physiological indicators of stress in 40 domestic rabbits. Neither blindfolding nor swaddling had significant impacts on heart or respiratory rate, compared to a partial hood control treatment, which involved similar levels of manipulation, but without visual or movement restriction. Behavioural responses showed variable trends, eg rabbits were more likely to approach food after handling with swaddling. Baseline levels varied significantly between individuals, suggesting previous experience to be an important determinant. Heart rates were universally high, showing that individuals in this study were stressed by handling to such an extent, that overall, effects of both blindfolding and swaddling on physiological indicators of stress were minimal. We suggest that blindfolding and swaddling may be useful as means of limiting the procedure duration and risk of injury by reducing struggling, but this study provides no evidence that welfare is otherwise improved.

Globally, calls for change in the horse industry to prioritise the health and well-being of domestic horses (Equus caballus) are reaching a critical threshold. Horse behaviour deemed undesirable or inconvenient by owners (henceforth referred to as undesirable behaviour) is reported across all aspects of a horse's life and may indicate a welfare issue. This study proposes a reconceptualisation of undesirable horse behaviour as a complex challenge based on systems thinking. Emerging from the natural sciences, systems thinking is an interdisciplinary approach to complex challenges (such as undesirable behaviour) as dynamic, highly interconnected networks of components and feedback relationships. This critical literature review examined the undesirable behaviours studied, the disciplines conducting research and their underpinning assumptions to identify opportunities for approaching research differently. Four themes emerged from the literature: undesirable behaviour is typically studied with unarticulated assumptions and in individual disciplines; behaviours are typically studied in isolation with the complexity of horse-human interactions generally not considered; management of behaviour typically has an anthropocentric linear ‘cause and effect’ focus; and solutions to undesirable behaviour are often short-term ‘fixes’ resulting in poor horse outcomes. From these, we outline the opportunities that each provide the next generation of horse research in terms of interdisciplinarity, systems thinking and management Undesirable horse behaviour in a horse-human system is conceptually mapped in terms of factors associated with the behaviour (eg housing, stress, diet), and the relationships between them. Systems thinking offers a way to integrate multiple disciplines and identify and navigate new solutions to promote horse welfare.

Norway rats (Rattus norvegicus) are considered one of the most significant vertebrate pests globally, because of their impacts on human and animal health. There are legal and moral obligations to minimise the impacts of wildlife management on animal welfare, yet there are few data on the relative welfare impacts of rat trapping and baiting methods used in the UK with which to inform management decisions. Two stakeholder workshops were facilitated to assess the relative welfare impacts of six lethal rat management methods using a welfare assessment model. Fifteen stakeholders including experts in wildlife management, rodent management, rodent biology, animal welfare science, and veterinary science and medicine, participated. The greatest welfare impacts were associated with three baiting methods, anticoagulants, cholecalciferol and non-toxic cellulose baits (severe to extreme impact for days), and with capture on a glue trap (extreme for hours) with concussive killing (mild to moderate for seconds to minutes); these methods should be considered last resorts from a welfare perspective. Lower impacts were associated with cage trapping (moderate to severe for hours) with concussive killing (moderate for minutes). The impact of snap trapping was highly variable (no impact to extreme for seconds to minutes). Snap traps should be regulated and tested to identify those that cause rapid unconsciousness; such traps might represent the most welfare-friendly option assessed for killing rats. Our results can be used to integrate consideration of rat welfare alongside other factors, including cost, efficacy, safety, non-target animal welfare and public acceptability when selecting management methods. We also highlight ways of reducing welfare impacts and areas where more data are needed.

Multiple benefits of freight rail activity have been shown for commercial agribusiness, yet the effects of freight rail-related noise and vibration on domestic livestock health and welfare has so far received little research attention. This scoping review examines peer-reviewed and grey literature addressing associations between freight rail noise, vibration and impacts on domestic livestock. Six databases (Scopus, Science Direct, SAGE, TRID, SPARK, ARRB) were searched for relevant literature published from 1980–2019. PRISMA search procedures were used to identify 28 publications relevant to domestic livestock, as well as noise or vibration impact of rail applicable to the freight rail context. Included publications addressed a range of livestock and related species, covering descriptive, review, and experimental findings on noise and vibration impacts. Five publications addressed vibration effects, and 23 addressed noise effects. Effects of noise and vibration on different species indicated that adverse effects vary depending on exposure intensity. The literature indicates that specific thresholds for noise and vibration exposure should be considered when managing freight rail impacts on commercial agribusiness involving avian and mammalian species. Freight rail noise and vibration likely exceeds thresholds for discomfort and harm for avian and mammalian species. Future research should consider case studies that specifically focus on integrating freight rail noise and vibration data to derive species-specific guides for animal health and welfare purposes.

Opercular deformity is a common morphological abnormality of laboratory and other cultured fishes, observed in a wide variety of species but with an unclear aetiology. Following observations of short opercula in stocks of Atlantic salmon (Salmo salar) reared in our laboratory, we developed a photographic key to score individual fish on a scale of 1 to 5. Inter-rater reliability was assessed as ‘almost perfect’. This visual method is quick and simple to use, can be used to score live fish in situ in tanks as well as sampled fish, does not require sophisticated equipment and provides quantitative information to investigate the aetiology of short opercula. Opercular size was scored for a cohort of in-house reared Atlantic salmon, in a time series of random samples of ≥ 30 fish (mean weights ranging from 0.8 to 299 g) over 14 months. Short opercula were first recorded during the parr stage, prevalence and severity increased as the fish grew, and the deformity was asymmetrical, occurring predominantly on the left side. Therefore, among the many potential causal factors, nipping is suggested as the primary cause of short opercula within our culture system, with asymmetry due to the clockwise current. We also present evidence that short opercula are associated with gill damage which supports this deformity being a welfare issue that merits assessment.

The purpose of this study was to assess the diversity of physiological stress responses elicited by tethering versus loose holding in the Swedish domestic goat (Capra hircus). Eight goats were randomly divided into two groups and the experiment was performed in a crossover design. Six goats had implanted transmitters that registered heart rate and arterial blood pressure telemetrically and blood samples were taken on separate days. Heart rate increased around feeding both when the goats were held loose in pairs, and when they were tied up. When the goats were tethered, the heart rates and blood pressures were higher, and the concentrations of ß-endorphin and oxytocin lower, compared to when held loose in pairs. In conclusion, housing and the company of another animal affect arterial blood pressure, heart rate, and the concentrations of ß-endorphin and oxytocin in goats, but the cortisol and vasopressin concentrations did not differ between the treatments. The higher arterial blood pressure and heart rate, and lower concentrations of ß-endorphin and oxytocin in tethered goats indicate that being tied up may be more stressful for the goats compared to being held loose. The use of single measures, eg cortisol concentrations, was not sufficient to give an accurate picture of the animals’ response to the management system. This study demonstrates the importance of using a wide variety of physiological measures when evaluating stress in animal welfare research.

Animal welfare is important for the humane treatment of animals under our care. Zoos and rescue centres manage various charismatic animals, such as big cats, with limited resources. It is therefore essential for caretakers to understand the needs of an individual big cat to ensure its welfare. However, these needs may differ due to a big cat's personality, which may be identified by its coping style in a stressful situation. In addition, stress is one of the major factors affecting animal welfare. There is limited evidence showing strong associations between personality and stress physiology in big cats. This review focuses on the integration of personality and stress physiology of captive big cats, to highlight possible improvements in their husbandry. Our review identifies key factors that may influence big cat responses to stressors. These influencing factors include: i) social interactions; ii) environment; iii) life history and evolutionary traits; iv) genetics; and v) health. The first two factors are relatively well covered in the literature; however, the final three are potentially very promising avenues for future research to better understand how we can improve big cat welfare.

The stranding of cetaceans raises significant welfare and associated logistical issues. A survey of opinions on euthanasia methods based on the recommendations of an International Whaling Commission (IWC) workshop was conducted. Descriptive statistics showed that the workshop recommendations were generally supported and understood, and these included the use of specific euthanasia techniques, but important barriers to adherence were identified, including lack of governmental support, lack of resources, and lack of experienced or trained personnel. Conjoint analysis of factors identified that ‘time to death’ was considered the most important determinant of welfare outcome. In view of the findings of this study, it is recommended that the IWC should consider creating a training programme for responders (both veterinary and non-veterinary) to ensure that trained personnel are available who can implement timely and tailored euthanasia techniques, if required, when strandings occur. Further research on this topic is also advocated to ensure a better understanding of what is being applied in different nations.

Abnormal behaviour in captive animals is both pervasive and ambiguous. Although individual differences are central to the field of animal welfare, studies on abnormal behaviour predominantly employ quantitative, population-level approaches. For example, whereas previous studies on chimpanzee (Pan troglodytes) abnormal behaviour have reported significant variation between groups or individuals in the quantity (eg frequency and duration) of abnormal behaviour, much less is known about qualitative differences. Individual abnormal behavioural repertoires may be highly idiosyncratic, where certain behaviours are over-represented (ie individually specific abnormal behavioural ‘signatures’). The present study investigated qualitative individual variation in the abnormal behaviour of chimpanzees (n = 15) housed at Royal Burgers’ Zoo in Arnhem, The Netherlands. Substantial variation was found between individuals in the diversity (size and evenness) and overall composition of their abnormal behavioural repertoires. Factors including age, sex, and rank did not significantly account for dissimilarity of individuals’ abnormal behavioural repertoires, but kin dyads showed more similar abnormal behaviour than non-kin dyads. Further exploratory analyses examined whether individual variation in one abnormal behaviour (coprophagy) predicted variation in stress-related behaviour (self-scratching). This allowed us to tentatively conclude that there were also individual differences in the link between a given abnormal behaviour and the behavioural expression of stress. Qualitative individual variation in abnormal behaviour provides a novel angle to a literature traditionally focused on quantifying abnormal behaviour at the group- or species-level and may thus represent an important yet previously overlooked source of variation in the extent to which abnormal behaviour reflects the state of individual welfare.

Empathy and anthropomorphism, well-established components of the human-pet relationship, are considered to be especially related to pet animal welfare. We have developed a systematic and standardised approach to explore the effect of the human-pet relationship on animal welfare, focusing on pet birds. Based on a data set measuring the owner-bird relationship as well as bird welfare, cluster analysis and multivariate regressions were used to identify empirical types of bird owners and analyse their effect on bird welfare. Five empirical types of bird owners were identified based on the multi-dimensional relationship between owner and bird which consisted of: (i) the closeness-appreciating anthropomorphising owner; (ii) the closeness-appreciating socially supported owner; (iii) the anthropomorphising socially supported owner; (iv) the inattentive owner; and (v) the distance-appreciating owner. These differed in terms of the owner's tendency to anthropomorphism, the social support the bird provides to the owner, the empathy, attentiveness and respect of the owner towards the bird, and the bird's relationship with the owner. In particular, the inattentive type, but also both anthropomorphising types, raised serious questions as to the well-being of the pet bird. We found significant correlations to bird behaviour, such as imprinting aspects, aggressiveness towards humans, conspecifics and other pet animals, as well as behavioural disorders, such as locomotor stereotypies, courtship behaviour towards humans and feather-plucking.

All cephalopod molluscs and decapod crustaceans should be regarded as sentient and protected under UK animal welfare law. This is the headline conclusion of this thoughtful report, that is going to have a profound impact on the way these animals are treated within the UK — and likely inform policy elsewhere. In response, the UK government has indicated that they accept this position and will look to/have extended forthcoming animal welfare legislation to include lobsters, octopus and crabs and all other decapod crustaceans and cephalopod molluscs.

The Nuffield Council on Bioethics has published in December 2021 their most recent report on the social and ethical issues associated with the use of genome editing in farm animal breeding. The Nuffield Council on Bioethics is an independent body based in the United Kingdom that examines and advises on ethical issues arising from developments in bioscience and health. The Council is made up of around 15 members and 12 executive staff. It was established by the trustees of the Nuffield Foundation in 1991, is funded jointly by the Nuffield Foundation, the Medical Research Council and Wellcome. One of their terms of reference is to identify and define ethical questions raised by recent developments in biological and medical research that concern, or are likely to concern, the public interest; and the Council reviews the available evidence with a view to report on these matters and to make recommendations relating to policy and practice.