Technical Contribution: A Cautionary Note on the Use of Behavioural Diversity (H-Index) in Animal Welfare Science

Consider the Source: The Impact of Social Mixing on Drylot Housed Steer Behavior and Productivity

Cattle are a social species in which social mixing can induce physical and psychosocial stress; however, the impact of social mixing on cattle welfare is unknown. Two different sources of genetically similar Angus crossbred steers were transported to the same feedlot and assigned to a pen where they were either socially mixed or housed with individuals from their source herds. Social mixing did not impact average daily gains in pens, feed intake, or feed efficiency; pens of socially mixed steers were more active. Sources differed in their responses to social mixing. One source was unaffected, whereas social mixing negatively impacted productivity for the other source. Irrespective of social mixing, the sources differed in the amount of time per day they spent ruminating and drinking. Group analyses indicated that socially mixing two sources of feedlot steers did not negatively impact group productivity, yet the impacts that were observed at the individual level suggest that prior experiences may influence their ability to cope with social stress, emphasizing the importance of early-life experiences to long-term welfare and productivity. Social mixing was not universally detrimental to cattle welfare, and the source of cattle may have the greatest affect on their performance regardless of whether a social mixing event has occurred.

Zoo Animal Welfare Assessment: Where Do We Stand?

Zoological institutions, such as zoos and aquariums, have made animal welfare a top priority, as it is not only a moral obligation but also crucial for fulfilling their roles in education and conservation. There is a need for science-based tools to assess and monitor animal welfare in these settings. However, assessing the welfare of zoo animals is challenging due to the diversity of species and lack of knowledge on their specific needs. This review aims to discuss the advantages and disadvantages of existing methodologies for assessing zoo animal welfare through: (1) A critical analysis of the main approaches to zoo animal welfare assessment; (2) A description of the most relevant animal-based welfare indicators for zoo animals with a particular focus on behavioural and physiological indicators; and (3) An identification of areas that require further research.

A Pilot Study on Behavioural and Physiological Indicators of Emotions in Donkeys

Recognizing animal emotions is critical to their welfare and can lead to a better relationship with humans and the environment, especially in a widespread species like the donkey, which is often prone to welfare issues. This study aims to assess the emotional response of donkeys through an operant conditioning task with two presumed different emotional contents. Specifically, a within-subject design including positive and negative conditions was conducted, collecting behavioural and physiological (heart rate variability and HRV) parameters. Facial expressions, postures, and movements were analysed by principal component analysis and behavioural diversity indexes (frequencies, activity budgets, richness, Shannon and Gini-Simpson). During the positive condition, both ears were held high and sideways (left: r = -0.793, p < 0.0001; right: r = -0.585, p = 0.011), while the ears were frontally erected (left: r = 0.924, p < 0.0001; right: r = 0.946, p < 0.0001) during the negative one. The latter was also associated with an increased tendency to walk (r = 0.709, p = 0.001), walk away (r = 0.578, p = 0.012), more frequent changes in the body position (V_{Body position} = 0, p = 0.022), and greater behavioural complexity (V_{Gini-Simpson Index} = 4, p = 0.027). As for HRV analysis, the root mean square of successive beat-to-beat differences (rMSSD) was significantly lower after the negative condition. These non-invasive parameters could be considered as possible indicators of donkeys' emotional state.

The Impacts of Evening Events in Zoos: A Christmas Event at Knowsley Safari

It is important to examine the animal welfare implications of all aspects of zoo operations, including out-of-hours public events. Research to date has indicated variable responses across species and event types. The current research aimed to understand and quantify the impact of a Christmas lights event. Four species of ungulates: Rothschild giraffe (Giraffa camelopardalis rothschildi; n = 2) in one exhibit and capybara (Hydrochoerus hydrochaeris; n = 4), lowland tapir (Tapirus terrestris; n = 3) and vicuña (Lama vicugna; n = 5) in a mixed species exhibit were observed. Data were collected from 16:00–20:00 between 28 October 2021 and 11 January 2022. The event ran from mid-November to the end of December 2021. Five-minute behavioural observations were undertaken once per hour using instantaneous scan sampling with a one-minute inter-scan interval. A further six days of 12 h observations were conducted to enable a more detailed investigation post-event. Data collected were compared on non-event and event days using Mann–Whitney U tests (event vs. non-event) and Kruskal–Wallis tests (pre-event, event, post-event periods). Kruskal–Wallis tests and one-way ANOVAs were undertaken to compare behaviours during three time periods (12:00–16:00, 16:00–20:00, 20:00–00:00) over 12 h. Mixed behavioural responses were seen across the study species. Capybara spent more time in their house from 16:00–20:00 on event nights compared to non-event nights (p < 0.001) and tapir only engaged in vigilant behaviour from 16:00–20:00 when the event was held, (p = 0.044). There were no differences in frequency of behaviour between pre-event, event, and post-event observation periods, with the exception of capybara, who spent more time OOS in the pre-event period than during (p < 0.001) or after the event (p < 0.001). The results of the project, undertaken as part of an evidence-based management programme, highlighted that the event did not have any overtly negative impacts on the ungulates studied. Except for the giraffe, all individuals had free access to inside and outside environments, and it is believed this choice enabled animals to be active in managing their response to the event. It is recommended that future work observe animals over 24 h to understand whether events lead to behavioural changes the day after events or if animals reverted to normal activity once the event ended.

Distinguishing mobility and immobility when establishing species-specific activity budgets: A case study with gorillas (Gorilla berengei berengei and Gorilla gorilla gorilla)

Activity budgets characterize the distribution of behavior over a specified time period. In some cases, having comparable data from free-ranging populations can help inform the management of wildlife in zoos and sanctuaries. For example, although variations exist across subspecies, seasons, and study sites, diurnal activity budgets for free-ranging gorillas largely consist of feeding and resting. Unfortunately, most studies do not consistently differentiate between the type of activities gorillas exhibit while locomoting versus stationary. Therefore, it can be difficult to characterize optimal levels of aerobic activity that might enhance body condition or promote gorilla health in zoos and sanctuaries. In this study, we concurrently measured the mobility state and activity of mountain gorillas (Gorilla beringei beringei) in Volcanoes National Park, Rwanda. From June to August 2015, behavioral data were collected using group scan sampling with 15-min intervals in two groups (N = 29 gorillas) monitored by the Dian Fossey Gorilla Fund International. Overall, gorillas spent significantly more time immobile (85.2% of observations) than mobile (14.8%), revealing energy expenditure levels comparable to western lowland gorillas living in zoos. There was no difference in behavioral diversity when gorillas were mobile versus immobile but adult females exhibited substantially less behavioral diversity while immobile than other age-sex classes. There was more diversity in behaviors following the transition from immobile to mobile than vice versa, particularly for adult females. Future studies should concurrently measure mobility state and behavior to improve the precision of activity budget data and serve as a more useful tool for evaluating optimal activity levels for wildlife in human care.

Investigating Unused Tools for the Animal Behavioral Diversity Toolkit

Behavioral diversity is a commonly used tool used to quantify the richness and evenness of animal behaviors and assess the effect of variables that may impact an animal's quality of life. The indices used in behavioral diversity research, and the study subjects, have not been formally reviewed. This paper aims to identify which indices are being used in behavioral diversity research, and under which scenarios, and uncover novel indices from other disciplines that could be applied to behavioral diversity. To investigate the techniques and species investigated in behavioral diversity literature, a Web of Science literature search was conducted. Two methods: behavioral richness and the Shannon-Wiener index, were the most frequently used indices, whereas the Behavioral Variability index featured rarely. While a range of species appeared in the behavioral literature, mammals were the most frequently studied Class, whereas amphibians did not feature in any papers. There are several diversity indices which did not feature in behavioral diversity including Simpson's index, and Chao. Such indices could be used to better understand animal behavioral study outputs or be used to estimate the number of 'unobserved' behaviors that an animal may express. Future studies could therefore extend beyond the Shannon-Wiener and richness indices.

Enrichment Is Simple, That’s the Problem: Using Outcome-Based Husbandry to Shift from Enrichment to Experience

Simple Summary

As animal care practitioners continue to advance husbandry practices, traditional methodologies are continually being reevaluated with a critical eye on efficacy. When evaluating practices designed to maximize wildlife care and welfare, environmental enrichment remains one of the most well-documented and deployed strategies in the managed care of wildlife. Enrichment does, however, have limitations and is most often considered a supplemental component of animal care. It is the supplemental nature of traditional enrichment that lends itself to being overly dependent on inputs from caretakers and lacks relevance to the natural history of the species. By utilizing a tool to highlight relevant outcomes when designing husbandry programs, it is our position that animals in managed care can have a more complete experience that is relative to their adaptations. The provisioning of resources, facilitation of self-maintenance, and care programs that require animal-driven choices may be able to dispel the notion that enrichment is required to augment typical animal care.

Abstract

Over the decades, the use of environmental enrichment has evolved from a necessary treatment to a “best practice” in virtually all wildlife care settings. The breadth of this evolution has widened to include more complex inputs, comprehensive evaluation of efficacy, and countless commercially available products designed to provide for a myriad of species-typical needs. Environmental enrichment, however, remains almost inexorably based on the provision of inputs (objects, manipulanda, or other sensory stimuli) intended to enhance an environment or prolong a specific behavior. Considerable effort has been put into developing enrichment strategies based on behavioral outcomes to shift the paradigm from the traditional input-heavy process. We believe that this trajectory can be enhanced through Outcome-Based Husbandry using an ethologically based workflow tool with a universal application (regardless of species) that flushes out inputs based on desired outcomes, which can then be incorporated into daily care or layered to create sensory cue-based multi-day events. Furthermore, we believe that this strategy can drive practitioners from the confines of traditional enrichment and the object-based approach into a dynamic and holistic husbandry program that synthesizes complex experiences into regular animal care, rather than supplementing husbandry with input-based enrichment. Focusing on an animal’s complete experience and outcomes that promote competence building and the highest level of agency allows the animals, not care staff, to make meaningful decisions that impact their present and future selves.

Behavioral Assessment of Six Reptile Species during a Temporary Zoo Closure and Reopening

Simple Summary

Reptile welfare in captivity is vastly understudied given the diverse taxa and the large number of individuals held in zoos and aquariums. The varied natural ecologies of reptiles have the potential to impact how they perceive different stimuli, including zoo visitors. The current study aimed to explore the impact of visitors through observations on small groups of six reptile species during a temporary zoo closure due to the COVID-19 pandemic by measuring behavioral diversity, use of enclosure space, and select behaviors. The majority of the species showed intermediate responses to the change in visitor presence that varied in valence; however, some responses were more pronounced.

Abstract

Although reptiles are commonly housed in zoos and aquariums, their welfare is understudied for the diversity of species housed and the taxon’s current captive population size. The sensory abilities of reptiles have adapted to the varied ecological niches they inhabit, and these evolutionary adaptations impact how reptiles perceive the stimuli around them—including zoo visitors. This study aimed to assess visitor effects on small groups of six reptile species during a temporary zoo closure due to COVID-19 by measuring behavioral diversity, use of space (measured by a spread of participation index), and select behaviors. The species assessed showed diverse responses. The Catalina Island rattlesnakes (Crotalus catalinensis) demonstrated increased investigation and behavioral diversity after the zoo reopened compared to when the zoo was closed, but the European glass lizards (Pseudopus apodus) showed decreases in the amount of time spent exposed to the observers’ view and in their evenness of space use after the zoo was reopened to visitors. The other species, including beaded lizards (Heloderma horridum), Sonoran spiny-tailed iguana (Ctenosaura macrolopha), Arrau turtles (Podocnemis expansa), and dwarf caimans (Paleosuchus palpebrosus), had intermediate changes in their responses to visitor presence.

Welfare Assessment Tools in Zoos: From Theory to Practice

Zoos are increasingly implementing formalized animal welfare assessment programs to allow monitoring of welfare over time, as well as to aid in resource prioritization. These programs tend to rely on assessment tools that incorporate resource-based and observational animal-focused measures. A narrative review of the literature was conducted to bring together recent studies examining welfare assessment methods in zoo animals. A summary of these methods is provided, with advantages and limitations of the approaches presented. We then highlight practical considerations with respect to implementation of these tools into practice, for example scoring schemes, weighting of criteria, and innate animal factors for consideration. It is concluded that there would be value in standardizing guidelines for development of welfare assessment tools since zoo accreditation bodies rarely prescribe these. There is also a need to develop taxon or species-specific assessment tools to complement more generic processes and more directly inform welfare management.

Overlooked and Under-Studied: A Review of Evidence-Based Enrichment in Varanidae

Enrichment has become a key aspect of captive husbandry practices as a means of improving animal welfare by increasing environmental stimuli. However, the enrichment methods that are most effective varies both between and within species, and thus evaluation underpins successful enrichment programs. Enrichment methods are typically based upon previously reported successes and those primarily with mammals, with one of the main goals of enrichment research being to facilitate predictions about which methods may be most effective for a particular species. Yet, despite growing evidence that enrichment is beneficial for reptiles, there is limited research on enrichment for Varanidae, a group of lizards known as monitor lizards. As a result, it can be difficult for keepers to implement effective enrichment programs as time is a large limiting factor. In order for appropriate and novel enrichment methods to be created, it is necessary to understand a species’ natural ecology, abilities, and how they perceive the world around them. This is more difficult for non-mammalian species as the human-centered lens can be a hinderance, and thus reptile enrichment research is slow and lagging behind that of higher vertebrates. This review discusses the physiological, cognitive, and behavioral abilities of Varanidae to suggest enrichment methods that may be most effective.

Behavioural diversity as a potential welfare indicator for professionally managed chimpanzees (Pan troglodytes): Exploring variations in calculating diversity using species-specific behaviours

Behavioural diversity may serve as a positive indicator of animal welfare that can be applied in long-term monitoring schemes in managed settings (eg zoos, laboratories, farms). Behavioural diversity is often higher when animals live in stimulating environments and experience positive events. Unfortunately, welfare researchers have not adopted consistent, standardised approaches to measuring behavioural diversity. The goal of this exploratory study was to utilise data from 41 adult chimpanzees (Pan troglodytes) housed across 16 zoological institutions to examine various models of Shannon's Diversity Index. Specifically, we investigated the impact of: combining versus splitting behaviours, including only positive behaviours, including human interaction, and considering recipient behaviours. We evaluate how the inclusion or exclusion of different behaviours impacts the relationship of behavioural diversity with: (i) concentrations of faecal glucocorticoid metabolites (GCM), a common indicator of adrenal activity; (ii) concentrations of immunoglobulin-A (IgA), an indicator of immune function and potential indicator of positive welfare; and (iii) stereotypic behaviour, a validated indicator of poor welfare. Most indices had significant negative relationships with faecal GCM. Animals that express a variety of behaviours from their species-typical repertoire have lower average faecal GCM concentrations and are likely experiencing better welfare. We did not find significant relationships between the behavioural diversity indices and IgA concentrations. Two indices were inversely associated with stereotypic behaviour. Our findings provide additional support for using Shannon's Diversity Index to calculate behavioural diversity as a robust, valid measure of positive welfare. However, future publications must justify the process for including or excluding behaviours from calculations.

Does Smart Farming Improve or Damage Animal Welfare? Technology and What Animals Want

“Smart” or “precision” farming has revolutionized crop agriculture but its application to livestock farming has raised ethical concerns because of its possible adverse effects on animal welfare. With rising public concern for animal welfare across the world, some people see the efficiency gains offered by the new technology as a direct threat to the animals themselves, allowing producers to get “more for less” in the interests of profit. Others see major welfare advantages through life-long health monitoring, delivery of individual care and optimization of environmental conditions. The answer to the question of whether smart farming improves or damages animal welfare is likely to depend on three main factors. Firstly, much will depend on how welfare is defined and the extent to which politicians, scientists, farmers and members of the public can agree on what welfare means and so come to a common view on how to judge how it is impacted by technology. Defining welfare as a combination of good health and what the animals themselves want provides a unifying and animal-centered way forward. It can also be directly adapted for computer recognition of welfare. A second critical factor will be whether high welfare standards are made a priority within smart farming systems. To achieve this, it will be necessary both to develop computer algorithms that can recognize welfare to the satisfaction of both the public and farmers and also to build good welfare into the control and decision-making of smart systems. What will matter most in the end, however, is a third factor, which is whether smart farming can actually deliver its promised improvements in animal welfare when applied in the real world. An ethical evaluation will only be possible when the new technologies are more widely deployed on commercial farms and their full social, environmental, financial and welfare implications become apparent.

Conducting Behavioural Research in the Zoo: A Guide to Ten Important Methods, Concepts and Theories

Behavioural research in zoos is commonplace and is used in the diagnosis and treatment of potential husbandry and management challenges. Robust methods that allow valid data collection and analysis constitute an evidence-based approach to animal care. Understanding behaviour is essential to improving animal management, and behavioural research is therefore popular, with a wide choice of behavioural methodologies and theories available. This review outlines ten methodological approaches, concepts or theories essential to zoo science that are based around behavioural observation. This list is not exhaustive but aims to define and describe key areas of consideration when planning and implementing a zoo-based behavioural project. We discuss the application of well-established methods (the construction of ethograms, use of time–activity patterns and measurement of space/enclosure use) as well as evaluating newer or less-widely applied analytical techniques, such as behavioural diversity indices, social networks analysis and Qualitative Behavioural Assessment. We also consider the importance of fundamental research methods, the application of pure science to understand and interpret zoo animal behaviour (with a review of a Tinbergian approach) and consideration of meta-analyses. The integration of observational techniques into experiments that aim to identify the cause and effect of behavioural performance is then explored, and we examine the assimilation of behavioural methods used in studies of environmental enrichment. By systematically studying animal behaviour, we can attempt to understand the welfare of individual animals in captivity, and here we present an example of our reviewed approaches to this area of zoo science. Combining multiple methodologies can lead to a greater understanding of behaviour and welfare, creating robust research, progressing husbandry and advancing conservation strategies. Collaborations between zoological collections and academic researchers (e.g., in Higher Education Institutions) can further refine and enhance the validity of research and husbandry practice alike.

Assessing Animal Welfare with Behavior: Onward with Caution

An emphasis on ensuring animal welfare is growing in zoo and aquarium associations around the globe. This has led to a focus on measures of welfare outcomes for individual animals. Observations and interpretations of behavior are the most widely used outcome-based measures of animal welfare. They commonly serve as a diagnostic tool from which practitioners make animal welfare decisions and suggest treatments, yet errors in data collection and interpretation can lead to the potential for misdiagnosis. We describe the perils of incorrect welfare diagnoses and common mistakes in applying behavior-based tools. The missteps that can be made in behavioral assessment include mismatches between definitions of animal welfare and collected data, lack of alternative explanations, faulty logic, behavior interpreted out of context, murky assumptions, lack of behavior definitions, and poor justification for assigning a welfare value to a specific behavior. Misdiagnosing the welfare state of an animal has negative consequences. These include continued poor welfare states, inappropriate use of resources, lack of understanding of welfare mechanisms and the perpetuation of the previously mentioned faulty logic throughout the wider scientific community. We provide recommendations for assessing behavior-based welfare tools, and guidance for those developing tools and interpreting data.

Administering an appeasing substance to beef calves at weaning to optimize productive and health responses during a 42-d preconditioning program

This experiment evaluated the impacts of administering a bovine appeasing substance (BAS) to beef calves at weaning on their performance, physiological responses, and behavior during a 42-d preconditioning program. Eighty calves (40 heifers and 40 steers; 90% British × 10% Nellore) were weaned at 233 ± 2 d of age (day 0); ranked by sex, weaning age, and body weight (BW); and assigned to receive BAS (IRSEA Group, Quartier Salignan, France; n = 40) or placebo (diethylene glycol monoethyl ether; CON; n = 40). Treatments (5 mL) were topically applied to the nuchal skin area of each animal following dam separation. Within treatment, calves were allocated to one of eight drylot pens (four pens per treatment; pen being the experimental unit) and received a free-choice total mixed ration (TMR) from day 0 to 42, intake of which was assessed daily. Live behavior observations were conducted on days 1, 2, 4, 8, 16, and 32. Temperament was assessed and blood samples were collected via jugular venipuncture on days -21, 0, 3, 7, 14, 28, and 42. Hair samples were collected from the tail switch on days 0, 14, 28, and 42. Calves were vaccinated against bovine respiratory disease viruses on days -21 and 0. Average daily gain from day 0 to 42 did not differ between treatments (P = 0.57) but was greater (P = 0.05) in BAS vs. CON calves from day 0 to 28. Intake of TMR was greater (P = 0.05) during the first week for BAS vs. CON calves (treatment × week; P = 0.08). The mean proportion of calves feeding simultaneously and performance of social and play behaviors were greater (P ≤ 0.05) for BAS vs. CON calves. Escape attempts were greater (P < 0.01) for BAS vs. CON calves on day 1 (treatment × day; P = 0.03). Exit velocity was greater (P = 0.04) for CON vs. BAS calves on day 14 and tended (P = 0.10) to be greater for CON vs. BAS calves on day 7 (treatment × day; P = 0.03). Mean plasma concentrations of haptoglobin were greater (P = 0.02) in CON vs. BAS calves. Hair cortisol concentrations were greater (P = 0.05) in CON vs. BAS calves on day 14 (treatment × day; P = 0.03). Mean serum concentrations of antibodies against bovine viral diarrhea virus were greater (P = 0.02) in BAS vs. CON calves. Collectively, BAS administration to beef calves at weaning alleviated stress-induced physiological reactions, improved temperament evaluated via chute exit velocity, enhanced humoral immunity acquired from vaccination, and appeared to have accelerated adaptation to novel management scheme and environment.

Evaluation of the Impact of Behavioral Opportunities on Four Zoo-Housed Aardvarks (Orycteropus afer)

Simple Summary

Evaluations of enrichment are critical to determine whether or not the goals of an enrichment program are being achieved. However, evaluations can be challenging if a species’ active period occurs outside of their caretakers’ normal schedule. Aardvarks are an understudied, nocturnal species, and our aim was to assess how they used their enrichment (nightly and throughout the study), if enrichment achieved the stated behavioral goals, and the subsequent effects of goal-achieving enrichment on the aardvarks’ welfare. Four aardvarks were given seven different enrichment items based on two behavioral goals, foraging and exploring, and were observed three times during the night. The aardvarks’ enrichment use was impacted based on the goal of the enrichment, with aardvarks using the enrichment aimed at promoting foraging behavior more when enrichment was first given compared to enrichment that promoted exploring. However, exploring enrichment was used more later in the night. The enrichment did appear to achieve the stated behavioral goals, and the aardvarks continued using the enrichment throughout the entire eight-week study. In addition, there were increased affiliative and decreased agonistic interactions with more enrichment use, linking the achievement of these goals to positive indicators of welfare. The data presented contribute to the current knowledge on goal-based enrichment and its impact on animal welfare.

Abstract

Evaluations of enrichment are critical to determine if an enrichment program is meeting stated goals. However, nocturnal species can present a challenge if their active periods do not align with caretakers’ schedules. To evaluate enrichment for four aardvarks housed with a natural light cycle, we provided seven different enrichment items aimed at fulfilling two behavioral goals: exploring and foraging. We wanted to understand how the aardvarks used enrichment, if enrichment promoted the defined goals, and how enrichment that achieves its goals affects welfare indicators, including rates of pacing and social behaviors, behavioral diversity, and fecal glucocorticoid metabolites. Twenty-minute observations from video were performed three times a night for a total of 224 observed hours. We found significant differences in how the aardvarks used items from the two enrichment goals throughout the night, with foraging enrichment used more than exploring at first and exploring enrichment used more later. We found that items promoted their defined goals, and aardvarks showed no evidence of habituation throughout the eight-week study. The impact on selected welfare indicators provided evidence of potentially positive changes, including increased affiliative and decreased agonistic interactions accompanying increases in goal behaviors. These results contribute to the current knowledge available on the impact of goal-directed behavioral opportunities on zoo animal welfare.

Behavioral Diversity as a Potential Indicator of Positive Animal Welfare

Modern day zoos and aquariums continuously assess the welfare of their animals and use evidence to make informed management decisions. Historically, many of the indicators of animal welfare used to assess the collection are negative indicators of welfare, such as stereotypic behavior. However, a lack of negative indicators of animal welfare does not demonstrate that an individual animal is thriving. There is a need for validated measures of positive animal welfare and there is a growing body of evidence that supports the use of behavioral diversity as a positive indicator of welfare. This includes an inverse relationship with stereotypic behavior as well as fecal glucocorticoid metabolites and is typically higher in situations thought to promote positive welfare. This review article highlights previous research on behavioral diversity as a potential positive indicator of welfare. Details are provided on how to calculate behavioral diversity and how to use it when evaluating animal welfare. Finally, the review will indicate how behavioral diversity can be used to inform an evidence-based management approach to animal care and welfare.