Sources of stress in captivity

Measuring animal welfare within a reintroduction: an assessment of different indices of stress in water voles Arvicola amphibius

Reintroductions are an increasingly common conservation restoration tool; however, little attention has hitherto been given to different methods for monitoring the stress encountered by reintroduced individuals. We compared ten potential measures of stress within four different categories (neuroendocrine, cell function, body condition and immune system function) as proxies for animal welfare in water voles being reintroduced to the Upper Thames region, Oxfordshire, UK. Captive-bred voles were assessed pre-release, and each month post-release for up to five months. Wild-born voles were captured in the field and assessed from two months post-release. Plasma corticosteroid, hydration and body condition of captive-bred voles differed between their pre-release measures and both their first (“short-term”) recapture, and their final recapture (“long-term” release), however only body condition and immunocompetence measured using the Nitroblue Tetrazolium (NBT) test were significantly different post-release between the first and last recaptures. Captive-bred animals had lower fat reserves, higher weight/length ratios and better immunocompetence (NBT) than did wild-born voles. Captive-bred males had higher ectoparasite burdens compared to wild-born males and, as reintroduction site quality decreased, became less hydrated. These observations indicate that some methods can identify changes in the stress response in individuals, highlighting areas of risk in a reintroduction programme. In addition, a single measure may not provide a full picture of the stress experienced; instead, a combination of measures of different physiological systems may give a more complete indication of stress during the reintroduction process. We highlight the need to monitor stress in reintroductions using measures from different physiological systems to inform on possible animal welfare improvements and thus the overall success rate of reintroductions.

Decreased litter size in inactive female mink (Neovison vison): Mediating variables and implications for overall productivity

Meagher, R., Bechard, A., Palme, R., Díez-León, M., Hunter, D. B. and Mason, G. 2012. Decreased litter size in inactive female mink ( Neovison vison ): Mediating variables and implications for overall productivity. Can. J. Anim. Sci. 92: 131–141. Farmed mink vary dramatically in activity: very inactive individuals rarely leave the nest-box, while others spend hours active daily, often performing stereotypic behaviour (SB). SB typically correlates with increased reproductive output, and inactivity, with decreased output. Our objectives were to determine whether SB or inactivity best predicted litter size (LS), and to test three hypothesized reasons for inactive dams’ reduced LS: H1, excess fat; H2, chronic stress (potentially underlying inactivity because fear motivates hiding); and H3, health problems. We assessed time budgets pre-breeding, scored body condition visually, conducted health exams, and assessed stress using faecal cortisol metabolites (FCM) and "glove tests" for fear. Results did not support H2 and H3: inactive females were no more fearful than active females (P>0.10), they excreted lower levels of FCM (P=0.033), and were considered healthy. As predicted by H1, inactive females had higher body condition scores (P<0.0001), which predicted decreased LS (P=0.040). However, path analysis determined this was unlikely to mediate the inactivity–LS relationship. Compared with SB, inactivity more consistently predicted both LS (negatively, P ≤ 0.038) and kit weight (positively, P ≤ 0.037). Therefore, decreasing inactivity in farmed mink, rather than increasing their SB or decreasing their body condition should most improve productivity.

Behavioral and hormonal consequences of transporting giant pandas from China to the United States

Zoological institutions strive to ensure the welfare of nonhuman animals in captivity. Part of this effort involves reducing the level of distress experienced by an animal to the greatest extent possible. However, some necessary zoo management practices such as transportation induce stress responses. An extensive literature exists concerning the animal welfare implications of road transportation for farm and laboratory animals. There has, however, been little focus on the effects of air transportation on wild animals in captivity. Because many endangered species are transported by air for breeding purposes, it is especially important to study the effects of stress on these species. This study investigated the behavioral and hormonal consequences of transporting 4 giant pandas (2 male-female pairs) by air from China to the United States. An autoregressive test revealed that urinary cortisol measures were highest for 2 subjects, Lun Lun and Tian Tian, during the flight than during the remainder of the 30-day period posttransport (p < .01). No long-term behavioral changes or problems emerged as a result of the transport. The study found that more research is needed to develop a complete understanding of transportation stress and welfare in captive wildlife.

MRI acoustic noise can harm experimental and companion animals

PURPOSE

To assess possible damage to the hearing of experimental and companion animal subjects of magnetic resonance imaging (MRI) scans.

MATERIALS AND METHODS

Using animal hearing threshold data and sound level measurements from typical MRI pulse sequences, we estimated "equivalent loudness" experienced by several experimental and companion animals commonly subjects of MRI scans. We compared the equivalent loudness and exam duration to safe noise standards set by the National Institute for Occupational Safety and Health (NIOSH).

RESULTS

Monkeys, dogs, cats, pigs, and rabbits are frequently exposed to equivalent loudness levels during MRI scans beyond what is considered safe for human exposure. The sensitive frequency ranges for rats and mice are shifted substantially upward and their equivalent loudness levels fall within the NIOSH safe zone.

CONCLUSION

MRI exposes many animals to levels of noise and duration that would exceed NIOSH human exposure limits. Researchers and veterinarians should use hearing protection for animals during MRI scans. Experimental research animals used in MRI studies are frequently kept and reimaged, and hearing loss could result in changed behavior. Damage to companion animals' hearing could make them less sensitive to commands and generally worsen interactions with family members. Much quieter MRI scanners would help decrease stress and potential harm to scanned animals, normalize physiology during MRI, and enable MRI of awake animals.

Heat or insulation: behavioral titration of mouse preference for warmth or access to a nest

In laboratories, mice are housed at 20-24°C, which is below their lower critical temperature (≈30°C). This increased thermal stress has the potential to alter scientific outcomes. Nesting material should allow for improved behavioral thermoregulation and thus alleviate this thermal stress. Nesting behavior should change with temperature and material, and the choice between nesting or thermotaxis (movement in response to temperature) should also depend on the balance of these factors, such that mice titrate nesting material against temperature. Naïve CD-1, BALB/c, and C57BL/6 mice (36 male and 36 female/strain in groups of 3) were housed in a set of 2 connected cages, each maintained at a different temperature using a water bath. One cage in each set was 20°C (Nesting cage; NC) while the other was one of 6 temperatures (Temperature cage; TC: 20, 23, 26, 29, 32, or 35°C). The NC contained one of 6 nesting provisions (0, 2, 4, 6, 8, or 10g), changed daily. Food intake and nest scores were measured in both cages. As the difference in temperature between paired cages increased, feed consumption in NC increased. Nesting provision altered differences in nest scores between the 2 paired temperatures. Nest scores in NC increased with increasing provision. In addition, temperature pairings altered the difference in nest scores with the smallest difference between locations at 26°C and 29°C. Mice transferred material from NC to TC but the likelihood of transfer decreased with increasing provision. Overall, mice of different strains and sexes prefer temperatures between 26-29°C and the shift from thermotaxis to nest building is seen between 6 and 10 g of material. Our results suggest that under normal laboratory temperatures, mice should be provided with no less than 6 grams of nesting material, but up to 10 grams may be needed to alleviate thermal distress under typical temperatures.

Behavioural indicators of welfare in farmed fish

Behaviour represents a reaction to the environment as fish perceive it and is therefore a key element of fish welfare. This review summarises the main findings on how behavioural changes have been used to assess welfare in farmed fish, using both functional and feeling-based approaches. Changes in foraging behaviour, ventilatory activity, aggression, individual and group swimming behaviour, stereotypic and abnormal behaviour have been linked with acute and chronic stressors in aquaculture and can therefore be regarded as likely indicators of poor welfare. On the contrary, measurements of exploratory behaviour, feed anticipatory activity and reward-related operant behaviour are beginning to be considered as indicators of positive emotions and welfare in fish. Despite the lack of scientific agreement about the existence of sentience in fish, the possibility that they are capable of both positive and negative emotions may contribute to the development of new strategies (e.g. environmental enrichment) to promote good welfare. Numerous studies that use behavioural indicators of welfare show that behavioural changes can be interpreted as either good or poor welfare depending on the fish species. It is therefore essential to understand the species-specific biology before drawing any conclusions in relation to welfare. In addition, different individuals within the same species may exhibit divergent coping strategies towards stressors, and what is tolerated by some individuals may be detrimental to others. Therefore, the assessment of welfare in a few individuals may not represent the average welfare of a group and vice versa. This underlines the need to develop on-farm, operational behavioural welfare indicators that can be easily used to assess not only the individual welfare but also the welfare of the whole group (e.g. spatial distribution). With the ongoing development of video technology and image processing, the on-farm surveillance of behaviour may in the near future represent a low-cost, noninvasive tool to assess the welfare of farmed fish.

Does immune suppression during stress occur to promote physical performance?

Two adaptationist hypotheses have been proposed to explain why stress, particularly elevation of stress hormones (i.e., glucocorticoids), tends to suppress immune functions. One is that immune suppression represents efforts to minimize autoimmune responses to self-antigens released as organisms cope with stressors (i.e., the autoimmune-avoidance hypothesis). The other is that immune suppression occurs to promote a shunting of resources to life processes more conducive to survival of the stressor (i.e., the re-allocation hypothesis). Here in wild-caught house sparrows (Passer domesticus), we tested the second hypothesis, asking whether sustained elevation of baseline glucocorticoids, due to captivity, caused a greater rate of decline in immune functions than flight performance. A greater decline in immune functions than flight performance would support the re-allocation hypothesis. As in previous studies, we found that captivity tended to alter baseline corticosterone, suggesting that house sparrows experience captivity as a stressor. Captivity also affected several constitutive and induced innate immune metrics: bacterial (Escherichia coli) killing activity (BKA) of blood and oxidative burst of leukocytes both changed in a manner consistent with immune disregulation. In contrast, breast muscle size and vertical flight (hovering) duration improved over captivity. Collectively, these changes provide indirect support for the re-allocation hypothesis, although within individuals, changes in immune and physical performance were unrelated.

Physiological and behavioural stress responses in cynomolgus macaques (Macaca fascicularis) to noise associated with construction work

The aim of the present study was to evaluate the behavioural and physiological responses to environmental disturbances (live and recorded dynamite explosions) in laboratory non-human primates in preparation for a future tunnel construction underneath our animal facility. In a pilot study (A) on 20 female Macaca fascicularis, a day of test blasts resulted in an increase in faecal cortisol and immunoreactive cortisol metabolites (CICM), and the animals reacted behaviourally with vertical flight and vocalizations. In a follow-up study (B), we assessed the impact of 10 days of exposure to recorded detonations on the behaviour and CICM in 16 M. fascicularis. In the latter study we introduced a predictive signal, serving as a conditional stimulus, to half of the animals. We found no significant effects of the noise in the Signal group; while the Control groups’ CICM values were affected. The behaviour was largely unaffected in the two groups. It was decided not to introduce a research moratorium on biomedical research planned to be conducted during the future tunnel construction, and that a conditional stimulus (‘warning signal’) will be used.

Physiological and proteomic evidences that domestication process differentially modulates the immune status of juvenile Eurasian perch (Perca fluviatilis) under chronic confinement stress

The current study aimed to evaluate the influence of domestication process on the stress response and subsequent immune modulation in Eurasian perch juveniles (Perca fluviatilis) submitted to chronic confinement. Briefly, F1 and F4 generations were confined into small-size tanks and sampled 7 and 55 days after stocking. Cortisol and glucose levels as well as lysozyme activity and immunoglobulin level were evaluated in the serum. Spleen Somatic Index and spleen ROS production were also measured. A proteomic analysis was performed on serum sampled on day 7. Finally, both generations were genetically characterized using a microsatellite approach. Globally, results revealed that chronic confinement did not elicit a typical stress response but resulted in a prolonged immune stimulation. Proteomic results suggested that domestication process influenced the immune status of perch submitted to chronic confinement as the F1 confined fish displayed lower abundance of C3 complement component, transferrin and Apolipoprotein E. Microsatellite data showed a strong genetic drift as well as reduced genetic diversity, allelic number and heterozygosity along with domestication process. The present work is the first to report that fish under domestication can develop an immune response, assessed by a combined approach, following recurrent challenges imposed by captive environment despite a reduced genetic variation.

Training large macaws for artificial insemination procedures

For some endangered parrot species, captive breeding may be the only insurance for their survival. However, many individuals in captivity do not reproduce. Artificial insemination (AI) may help overcome reproductive failures or geographic distance. For semen collection in birds, massage is the most commonly used method. However, this process, which usually requires capture and restraint, involves risk of stress and injuries. The aim of this experiment was to train large macaws to accept the physical manipulations of their body parts needed for the artificial insemination process. Within 15 weeks, a male and a female Buffon's macaw (Ara ambiguus) learned to accept handling without apparent stress. A pair of green-winged macaws (Ara chloropterus) progressed more slowly and displayed some signs of stress. This stress highlights the need to monitor the birds' possible signs of discomfort during the training in order to adapt the working protocol. These results demonstrate that it is possible to train the AI behaviors, thus avoiding the capture, restraint, and anesthesia. An added benefit to this is the potential for the training to provide a form of behavioral enrichment.

The effect of environmental enrichment and visitors on the behaviour and welfare of two captive hamadryas baboons (Papio hamadryas)

The welfare of zoo animals depends on a combination of physical, social, dietary and other ecological characteristics of the captive setting. We analysed the influence of the transfer of an adult couple of hamadryas baboons (Papio hamadryas) from a small and non-enriched cage that was closed to the public to a larger and enriched exhibit at the visitation area of the Sapucaia do Sul Zoological Park, RS, Brazil. A total of 350 h divided into four stages were spent observing the baboons: (i) in the non-enriched enclosure before the transfer; (ii) soon after the transfer to the enriched enclosure; (iii) six months; and (iv) 12 months after the transfer. The occurrence of stereotypic, social aggressive and social affiliative behaviours was recorded by ‘all occurrences’ sampling. The female showed a decrease in frequency of a stereotypic behaviour (spinning) and an increase in grooming in the enriched enclosure. The male showed a decrease in the frequency of certain stress-related or stereotypic behaviours after transfer, but other stress-related behaviours either increased or remained constant. The male behaviour of throwing faeces was affected by the presence of visitors. We suggest that the well-being of the female was more positively influenced by the new enclosure than that of the male, although gender differences may reflect the normal behavioural repertoire of this sexually dimorphic species.

Noninvasive monitoring of adrenocortical function in captive jaguars (Panthera onca)

Jaguars are threatened with extinction throughout their range. A sustainable captive population can serve as a hedge against extinction, but only if they are healthy and reproduce. Understanding how jaguars respond to stressors may help improve the captive environment and enhance their wellbeing. Thus, our objectives were to: (1) conduct an adrenocorticotrophic hormone (ACTH) challenge to validate a cortisol radioimmunoassay (RIA) for noninvasive monitoring of adrenocortical function in jaguars; (2) investigate the relationship between fecal corticoid (FCM) and androgen metabolite (FAM) concentrations in males during the ACTH challenge; and (3) establish a range of physiological concentrations of FCMs for the proposed protocol. Seven jaguars (3 M, 4 F) received 500 IU/animal of ACTH. Pre- and post-ACTH fecal samples were assayed for corticoid (M and F) and androgen metabolites (M) by RIA. Concentrations of FCMs increased (P80.01) after ACTH injection (pre-ACTH: 0.90 ± 0.12 µg/g dry feces; post-ACTH: 2.55 ± 0.25 µg/g). Considering pre- and post-ACTH samples, FCM concentrations were higher (P80.01) in males (2.15 ± 0.20 µg/g) than in females (1.30 ± 0.20 µg/g), but the magnitude of the response to ACTH was comparable (P>0.05) between genders. After ACTH injection, FAMs increased in two (of 3) males; in one male, FCMs and FAMs were positively correlated (0.60; P80.01). Excretion of FCMs was assessed in 16 jaguars (7 M, 9 F) and found to be highly variable (range, 80.11-1.56 µg/g). In conclusion, this study presents a cortisol RIA for monitoring adrenocortical function in jaguars noninvasively.

Host cytokine responses of pigeons infected with highly pathogenic Thai avian influenza viruses of subtype H5N1 isolated from wild birds

Highly pathogenic avian influenza virus (HPAIV) of the H5N1 subtype has been reported to infect pigeons asymptomatically or induce mild symptoms. However, host immune responses of pigeons inoculated with HPAIVs have not been well documented. To assess host responses of pigeons against HPAIV infection, we compared lethality, viral distribution and mRNA expression of immune related genes of pigeons infected with two HPAIVs (A/Pigeon/Thailand/VSMU-7-NPT/2004; Pigeon04 and A/Tree sparrow/Ratchaburi/VSMU-16-RBR/2005; T.sparrow05) isolated from wild birds in Thailand. The survival experiment showed that 25% of pigeons died within 2 weeks after the inoculation of two HPAIVs or medium only, suggesting that these viruses did not cause lethal infection in pigeons. Pigeon04 replicated in the lungs more efficiently than T.sparrow05 and spread to multiple extrapulmonary organs such as the brain, spleen, liver, kidney and rectum on days 2, 5 and 9 post infection. No severe lesion was observed in the lungs infected with Pigeon04 as well as T.sparrow05 throughout the collection periods. Encephalitis was occasionally observed in Pigeon04- or T.sparrow05-infected brain, the severity, however was mostly mild. To analyze the expression of immune-related genes in the infected pigeons, we established a quantitative real-time PCR analysis for 14 genes of pigeons. On day 2 post infection, Pigeon04 induced mRNA expression of Mx1, PKR and OAS to a greater extent than T.sparrow05 in the lungs, however their expressions were not up-regulated concomitantly on day 5 post infection when the peak viral replication was observed. Expressions of TLR3, IFNα, IL6, IL8 and CCL5 in the lungs following infection with the two HPAIVs were low. In sum, Pigeon04 exhibited efficient replication in the lungs compared to T.sparrow05, but did not induce excessive host cytokine expressions. Our study has provided the first insight into host immune responses of pigeons against HPAIV infection.

Captivity induces hyper-inflammation in the house sparrow (Passer domesticus)

Some species thrive in captivity but others exhibit extensive psychological and physiological deficits, which can be a challenge to animal husbandry and conservation as well as wild immunology. Here, we investigated whether captivity duration impacted the regulation of a key innate immune response, inflammation, of a common wild bird species, the house sparrow (Passer domesticus). Inflammation is one of the most commonly induced and fast-acting immune responses animals mount upon exposure to a parasite. However, attenuation and resolution of inflammatory responses are partly coordinated by glucocorticoid hormones, hormones that can be disregulated in captivity. Here, we tested whether captivity duration alters corticosterone regulation and hence the inflammatory response by comparing the following responses to lipopolysaccharide (LPS; a Gram-negative bacteria component that induces inflammation) of birds caught wild and injected immediately versus those held for 2 or 4 weeks in standard conditions: (1) the magnitude of leukocyte immune gene expression [the cytokines, interleukin 1β and interleukin 6, and Toll-like receptor 4 (TLR4)], (2) the rate of clearance of endotoxin, and (3) the release of corticosterone (CORT) in response to endotoxin (LPS). We predicted that captivity duration would increase baseline CORT and thus suppress gene expression and endotoxin clearance rate. However, our predictions were not supported: TLR4 expression increased with time in captivity irrespective of LPS, and cytokine expression to LPS was stronger the longer birds remained captive. Baseline CORT was not affected by captivity duration, but CORT release post-LPS occurred only in wild birds. Lastly, sparrows held captive for 4 weeks maintained significantly higher levels of circulating endotoxin than other groups, perhaps due to leakage of microbes from the gut, but exogenous LPS did not increase circulating levels over the time scale samples were collected. Altogether, captivity appears to have induced a hyper-inflammatory state in house sparrows, perhaps due to disregulation of glucocorticoids, natural microflora or both.

Environmental enrichment affects adrenocortical stress responses in the endangered black-footed ferret

Potential stressors of wildlife living in captivity, such as artificial living conditions and frequent human contact, may lead to a higher occurrence of disease and reduced reproductive function. One successful method used by wildlife managers to improve general well-being is the provision of environmental enrichment, which is the practice of providing animals under managed care with environmental stimuli. The black-footed ferret (Mustela nigripes) is a highly-endangered carnivore species that was rescued from extinction by removal of the last remaining individuals from the wild to begin an ex situ breeding program. Our goal was to examine the effect of environmental enrichment on adrenocortical activity in ferrets by monitoring fecal glucocorticoid metabolites (FGM). Results demonstrated that enrichment lowered FGM in juvenile male ferrets, while increasing it in adult females; enrichment had no effect on FGM in juvenile females and adult males. These results correspond with our findings that juvenile males interacted more with the enrichment items than did adult females. However, we did not detect an impact of FGM on the incidence of disease or on the ability of ferrets to become reproductive during the following breeding season. We conclude that an environmental enrichment program could benefit captive juvenile male ferrets by reducing adrenocortical activity.

Does environmental enrichment reduce stress? An integrated measure of corticosterone from feathers provides a novel perspective

Enrichment is widely used as tool for managing fearfulness, undesirable behaviors, and stress in captive animals, and for studying exploration and personality. Inconsistencies in previous studies of physiological and behavioral responses to enrichment led us to hypothesize that enrichment and its removal are stressful environmental changes to which the hormone corticosterone and fearfulness, activity, and exploration behaviors ought to be sensitive. We conducted two experiments with a captive population of wild-caught Clark's nutcrackers (Nucifraga columbiana) to assess responses to short- (10-d) and long-term (3-mo) enrichment, their removal, and the influence of novelty, within the same animal. Variation in an integrated measure of corticosterone from feathers, combined with video recordings of behaviors, suggests that how individuals perceive enrichment and its removal depends on the duration of exposure. Short- and long-term enrichment elicited different physiological responses, with the former acting as a stressor and birds exhibiting acclimation to the latter. Non-novel enrichment evoked the strongest corticosterone responses of all the treatments, suggesting that the second exposure to the same objects acted as a physiological cue, and that acclimation was overridden by negative past experience. Birds showed weak behavioral responses that were not related to corticosterone. By demonstrating that an integrated measure of glucocorticoid physiology varies significantly with changes to enrichment in the absence of agonistic interactions, our study sheds light on potential mechanisms driving physiological and behavioral responses to environmental change.

Sickness behaviors in response to unusual external events in healthy cats and cats with feline interstitial cystitis

OBJECTIVE

To compare sickness behaviors (SB) in response to unusual external events (UEE) in healthy cats with those of cats with feline interstitial cystitis (FIC).

DESIGN

Prospective observational study.

ANIMALS

12 healthy cats and 20 donated cats with FIC.

PROCEDURES

Cats were housed in a vivarium. Sickness behaviors referable to the gastrointestinal and urinary tracts, the skin, and behavior problems were recorded by a single observer for 77 weeks. Instances of UEE (eg, changes in caretakers, vivarium routine, and lack of interaction with the investigator) were identified during 11 of the 77 weeks. No instances of UEE were identified during the remaining 66 weeks, which were considered control weeks.

RESULTS

An increase in age and exposure to UEE, but not disease status, significantly increased total number of SB when results were controlled for other factors. Evaluation of individual SB revealed a protective effect of food intake for healthy males. An increase in age conferred a small increase in relative risk (RR) for upper gastrointestinal tract signs (RR, 1.2) and avoidance behavior (1.7). Exposure to UEE significantly increased the RR for decreases in food intake (RR, 9.3) and for no eliminations in 24 hours (6.4). Exposure to UEE significantly increased the RR for defecation (RR, 9.8) and urination (1.6) outside the litter box.

CONCLUSIONS AND CLINICAL RELEVANCE

SB, including some of the most commonly observed abnormalities in client-owned cats, were observed after exposure to UEE in both groups. Because healthy cats and cats with FIC were comparably affected by UEE, clinicians should consider the possibility of exposure to UEE in cats evaluated for these signs.

Behavioral indexes of piglet welfare: comparison of indoor and outdoor housing systems

The purpose of this experiment was to establish behavioral indexes of piglet welfare. Forty-eight piglets were allocated to either four indoor pens or four outdoor pens (six piglets per pen). The indoor system was a commercial pen that consisted of a concrete floor and a slat floor. The outdoor system had a dirt paddock with a wooden hutch. Growth performance, salivary cortisol levels, skin lesions and behaviors of the piglets were monitored for 4 weeks. Sixteen types of behaviors were recorded by using 2-min instantaneous scan sampling for 8 h/day. Growth performance and salivary cortisol levels did not significantly differ between the two housing systems. On the other hand, skin lesions and behaviors were significantly affected by the housing system. The number of skin lesions was higher in the indoor system. In addition, piglets in the outdoor system showed more investigative and social-play behaviors than those in the indoor system. Piglets in the indoor system showed more resting, drinking, moving, fighting, and conflict behaviors than those in the outdoor system. We conclude that investigative, social-play and conflict behaviors may be effective indexes of the welfare level of piglets, especially investigative and conflict behaviors.

Born to choose: the origins and value of the need for control

Belief in one's ability to exert control over the environment and to produce desired results is essential for an individual's wellbeing. It has repeatedly been argued that perception of control is not only desirable, but is also probably a psychological and biological necessity. In this article, we review the literature supporting this claim and present evidence of a biological basis for the need for control and for choice-that is, the means by which we exercise control over the environment. Converging evidence from animal research, clinical studies and neuroimaging suggests that the need for control is a biological imperative for survival, and a corticostriatal network is implicated as the neural substrate of this adaptive behavior.

Contrafreeloading in grizzly bears: implications for captive foraging enrichment

Although traditional feeding regimens for captive animals were focused on meeting physiological needs to assure good health, more recently emphasis has also been placed on non-nutritive aspects of feeding. The provision of foraging materials to diversify feeding behavior is a common practice in zoos but selective consumption of foraging enrichment items over more balanced "chow" diets could lead to nutrient imbalance. One alternative is to provide balanced diets in a contrafreeloading paradigm. Contrafreeloading occurs when animals choose resources that require effort to exploit when identical resources are freely available. To investigate contrafreeloading and its potential as a theoretical foundation for foraging enrichment, we conducted two experiments with captive grizzly bears (Ursus arctos horribilis). In Experiment 1, bears were presented with five foraging choices simultaneously: apples, apples in ice, salmon, salmon in ice, and plain ice under two levels of food restriction. Two measures of contrafreeloading were considered: weight of earned food consumed and time spent working for earned food. More free than earned food was eaten, with only two bears consuming food extracted from ice, but all bears spent more time manipulating ice containing salmon or apples than plain ice regardless of level of food restriction. In Experiment 2, food-restricted bears were presented with three foraging choices simultaneously: apples, apples inside a box, and an empty box. Although they ate more free than earned food, five bears consumed food from boxes and all spent more time manipulating boxes containing apples than empty boxes. Our findings support the provision of contrafreeloading opportunities as a foraging enrichment strategy for captive wildlife.

Haematological and biochemical responses of red foxes (Vulpes vulpes) to different capture methods and shooting

This paper sought to determine whether common haematology and blood biochemistry values might assist in determining the relative welfare outcomes arising from the capture of red foxes (Vulpes vulpes) by treadle-snares, Victor Soft Catch® (VSC) #3 traps, cage traps, netting and sampling by shooting. Compared to all other capture methods and shooting, treadle-snared foxes had significantly higher mean albumin (ALB), creatine kinase (CK), red cell count (RCC), neutrophil to lymphocyte (N:L) ratio, sodium (Na), total protein (TP), white cell counts (WCC) and lower glucose (Gl). Treadle-snares were also associated with higher chloride (Cl), haemoglobin (Hb) and packed cell volume (PCV) than cage trapping and netting. Treadle-snares produced indicators of possible muscle damage, exertion and dehydration compared to cage and VSC traps. Cage trapping and netting produced lower indications of exertion, possible muscle damage and dehydration compared to both treadle-snares and VSC traps. These data do not support previous conclusions that due to similar injury scores, treadle-snares and VSC traps produced equivalent welfare outcomes. In restraining traps, injury and death sustained during capture are end-points of poor trapping welfare. Monitoring stress using physiological indicators allows the comparison of the relative potential for different capture techniques to cause pathological and pre-pathological states. As the response of physiological indicators to stress is not independent of time, accurate data on the duration of captivity and the relative intensity of struggling behaviour should be routinely collected when assessing the comparative humaneness of different trap devices.

The conservation-welfare nexus in reintroduction programmes: a role for sensory ecology

Since reintroduction programmes involve moving animals from captive or wild environments and releasing them into novel environments, there are sure to be a number of challenges to the welfare of the individuals involved. Behavioural theory can help us develop reintroductions that are better for both the welfare of the individual and the conservation of populations. In addition to modifying captive environments to prepare animals for release to the wild, it is possible to modify the animals’ experience in the post-release environment. For releases to be more successful, they need to better accommodate the ecological and psychological needs of individuals. A better understanding of sensory ecology — how animals acquire and respond to information in their environment — is needed to develop new, more successful management strategies for reintroductions. Sensory ecology integrates ecological and psychological processes, calling for better synergy among researchers with divergent backgrounds in conservation and animal welfare science. This integrative approach leads to new topics of investigation in reintroduction biology, including more careful consideration of post-release stress and the role of social support. Reintroductions are essentially exercises in ‘forced’ dispersal; thus, an especially promising avenue of research is the role of proximate mechanisms governing dispersal and habitat selection decisions. Reintroduction biologists have much to gain from the study of mechanism because mechanisms, unlike function or adaptive value, can be manipulated to enhance conservation and welfare goals.

There are big gaps in our knowledge, and thus approach, to zoo animal welfare: a case for evidence-based zoo animal management

There are gaps in knowledge that hinder our ability within zoos to provide good animal welfare. This does not mean that zoos cannot or do not provide good welfare, only that currently this goal is hindered. Three reasons for these gaps are identified as: (1) there is an emphasis on the identification and monitoring of indicators that represent poor welfare and it is assumed that an absence of poor welfare equates to good welfare. This assumption is overly simplistic and potentially erroneous; (2) our understanding of how housing and husbandry (H&H) affects animals is limited to a small set of variables determined mostly by our anthropogenic sensitivities. Thus, we place more value on captive environmental variables like space and companionship, ignoring other factors that may have a greater impact on welfare, like climate; (3) finally, whether intentional or not, our knowledge and efforts to improve zoo animal welfare are biased to very few taxa. Most attention has been focused on mammals, notably primates, large cats, bears, and elephants, to the exclusion of the other numerous species about which very little is known. Unfortunately, the extent to which these gaps limit our ability to provide zoo animals with good welfare is exacerbated by our over reliance on using myth and tradition to determine zoo animal management. I suggest that we can fill these gaps in our knowledge and improve our ability to provide zoo animals with good welfare through the adoption of an evidence-based zoo animal management framework. This approach uses evidence gathered from different sources as a basis for making any management decisions, as good quality evidence increases the likelihood that these decisions result in good zoo animal welfare.

Euthanasia methods, corticosterone and haematocrit levels in Xenopus laevis: evidence for differences in stress?

Amphibians, like other vertebrates, respond to acute stressors by releasing glucocorticoid steroid hormones that mediate physiological and behavioural responses to stress. Measurement of stress hormones provides a potential means to improve the welfare of laboratory animals. For example, manipulations of laboratory housing and procedures combined with measurement of glucocorticoids may identify which conditions are more stressful to animals. This is important because there is very little experimental evidence to guide best practice for welfare in amphibians and other lower vertebrates. We investigated the effect of different methods of euthanasia on the circulating plasma corticosterone levels in the African clawed frog (Xenopus laevis), a model amphibian organism that is frequently used in laboratories. In particular, we investigated the effect of different concentrations and pH of the anaesthetic tricaine methanesulphonate (MS-222). Low concentration and unbuffered (low pH) solutions of MS-222 caused elevated corticosterone levels, but only after the effect of MS-222 treatment on blood fluid volume had been taken into account. The level of disturbance that animals experienced also affected corticosterone levels. Thus, our data suggest that to minimise stress to X. laevis, animals should be euthanised after minimal disturbance and in a 3 g L−1 MS-222 solution, buffered to pH 7. The potential for the improvement of amphibian welfare using corticosterone measures as a tool is discussed.