Welcome to the Refinement Database

Search scientific articles, books, and other publications related to improving or safeguarding the welfare of animals used in research and testing.

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The Refinement Database, launched by the Animal Welfare Institute (AWI) in 2000, is a curated collection of published scientific articles and books on topics related to the refinement of housing, husbandry, care, and use of animals in research and testing. The database is intended to provide the most up-to-date information on best practices for improving or safeguarding animal welfare. It is updated every four months; the most recent update was made in November 2025.

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You can also add a keyword in addition to using the Animal Type and Topic filters to further narrow your search. For example, after selecting Topic: Environmental Enrichment, you could add the keyword "music" to refine your search to publications on music-related environmental enrichment. Or, you could add an author's name to search for publications by a particular individual.

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Introduction With the growing number of veterinary centers performing pacemaker implantation in small animals, a better understanding of anesthetic management of these procedures has become essential. Most available studies focus primarily on surgical techniques, with limited discussion of anesthetic safety, efficacy, and intraoperative complications. Materials and methods Eighteen anesthetic procedures for transvenous pacemaker implantation were retrospectively reviewed in dogs treated at a veterinary referral center in São Paulo, Brazil, between 2024 and 2025. All dogs underwent clinical and laboratory evaluation, electrocardiography and/or Holter monitoring, and echocardiography. Continuous intraoperative monitoring included heart rate, electrocardiography, respiratory rate, end-tidal CO2, oxygen saturation, temperature, and invasive or non-invasive arterial blood pressure. Collected data included age, breed, sex, anesthetic protocol, clinical conditions, intraoperative events, and outcomes. Continuous variables were expressed as mean ± SD or median (range) according to data distribution assessed by the Shapiro–Wilk test. Group comparisons were performed using Student’s t-test or Mann–Whitney U test, and categorical variables were analyzed using chi-square or Fisher’s exact test (p < 0.05). Results Sixteen dogs (8 males and 8 females) underwent 18 anesthetic procedures, including two reinterventions. The main indication for pacemaker implantation was third-degree atrioventricular block (75%). Anesthetic protocols were individualized according to patient comorbidities. The most frequent anesthetic complication was hypotension (27.7%), successfully managed with fluid therapy and vasoactive support. Electrode migration occurred in 11% of procedures and required reintervention. No perioperative deaths were recorded. Discussion and conclusion Transvenous pacemaker implantation in dogs was successfully performed under individualized anesthetic management despite heterogeneous clinical conditions and absence of a standardized protocol. Hypotension was the most common anesthetic complication but was effectively treated. The routine use of temporary external pacing provided an essential safety margin for maintaining perioperative hemodynamic stability. No perioperative deaths were recorded. These findings support the feasibility and safety of tailored anesthetic strategies for canine pacemaker implantation, although prospective studies with larger populations are warranted to define optimal standardized protocols.

Monitoring the health and well-being of research animals is essential for both ethical and scientific purposes. In songbirds, body weight is one of the main indicators of their overall condition, yet traditional weighing methods can be intrusive and stress-inducing, which could decrease their song rate. We developed an automated system for monitoring the weight of multiple birds in longitudinal neuroscience experiments, which often include birds tethered to data acquisition systems. Building on previous models that were mostly designed for weighing birds outdoors and in large housing cages, our design serves as a perch for the bird to stand on (a perch-scale) and meets the needs of neuroscience experiments by (i) minimizing cable entanglement to safely accommodate tethered birds, (ii) supporting long-term monitoring of individually-housed birds, and (iii) linking multiple devices into a unified control unit that oversees setup, calibration, and data acquisition. We deployed the system in the cages of six canaries for ten days and validated its accuracy against daily manual weighing. The precision and continuous monitoring of the perch-scale allowed observing physiological patterns such as overnight weight loss. Our system detected 22 sequences of overnight perching in five different birds, showing an average decrease of ≈4% of the bird’s body-weight overnight. We also found that daily weight estimates, derived from perch-scale data, were within the range of daily weight fluctuations (5–10%), as they deviated by less than 5% on average when compared to the manual weights. These results validate the device’s sensitivity for detecting subtle and health-related changes. By eliminating the need for manual handling of birds, this system offers a non-invasive, hands-free approach that reduces stress and improves the accuracy of health assessments. Future applications could integrate additional health metrics to provide a more comprehensive understanding of animal welfare in neurophysiology and behavioral studies.

Assessing the welfare of zoo-housed great apes is essential to ensure high standards of care, maintain zoos’ ethical and educational credibility, and support their conservation roles. However, welfare assessment remains challenging due to the complex cognitive, social, and behavioural needs of great apes and the limitations of existing evaluation methods. Many zoos rely on resource-based measures, which are easy to collect but lack the specificity needed to assess welfare accurately. In this study, we developed and tested a new standardized, evidence-based approach that integrated resource-based data with ecological and behavioural insights. This Ape Welfare Assessment, Resources and Ecology (AWARE) Tool was developed through collaboration with the Great Ape Welfare group (GAWg) and aimed to: (1) collect a holistic suite of resource and husbandry data that measures the constraints on the apes opportunities to express key naturalistic behaviours, (2) contextualize results within species-specific research on wild and captive great ape behavioural ecology and welfare, and (3) extend beyond existing zoo accreditation standards to support zoos aspirations for higher levels of welfare. Using data from zoo-housed chimpanzees, we tested whether this approach enhanced the validity of resource-based welfare assessments. Results demonstrate that the approach strengthens welfare evaluations and provides a more nuanced understanding of captive great ape wellbeing. We also propose a new validation framework for holistic welfare assessment tools such as this, where validating all individual indicators is neither feasible nor informative. Ultimately, we aim for the AWARE Tool to serve as a web-based resource for independent zoo use and formal welfare assessments. Future research will expand its application to gorillas and orangutans. This study represents a major leap towards establishing robust, species-informed and validated welfare assessment methodologies for zoo-housed great apes.

In intensive commercial pig production systems, the spatial distribution of elimination and lying behaviors plays a crucial role in pen hygiene, management efficiency, and animal welfare. Pen partition design and the provision of hiding facilities are key structural factors that may influence pigs’ spatial preferences; however, systematic evaluations of their combined effects remain limited. A total of 108 growing–finishing pigs were used in a 3 × 2 factorial design to assess the effects of different partition types and hiding facility configurations, as well as their interaction, on the spatial distribution of elimination and lying behaviors. Behavioral data were analyzed using non-parametric statistical methods. The results showed that partition type and hiding facilities significantly influenced the spatial patterns of elimination and lying behaviors (p 0.05). Elimination behavior was predominantly concentrated in the slatted floor area. The combination of a front-closed partition with a hiding facility significantly increased the proportion of disturbed elimination events (16.2 ± 14.3%), which was higher than that observed in the open partition combined with a hiding facility (7.9 ± 7.6%, p < 0.05). In contrast, the rear-closed partition design was associated with atypical elimination occurring on the solid floor area. Overall, pigs showed a clear preference for lying on the solid floor. The front-closed partition combined with a hiding facility significantly reduced the proportion of lying on the solid floor (64.6 ± 8.5%), whereas the open partition combined with a hiding facility resulted in a higher-than-average proportion of solid-floor lying behavior (80.6 ± 8.9%). These findings indicate that an open partition design combined with a hiding facility is more effective in maintaining functional separation between elimination and resting areas while reducing disturbed elimination events. This study provides experimental evidence to support structural optimization of growing–finishing pig housing, contributing to improved pen hygiene and enhanced animal welfare.

Depression is one of the most common and impairing mental health disorders in humans. Captive animals may also experience depression-like states, particularly under restrictive housing conditions and in individuals with higher vulnerability to stressors (e.g. more fearful). This study investigated whether transferring laying hens (n = 60) from a cage-free environment to conventional battery cages led animals to display two core symptoms of clinical depression: anhedonia and low mood during the first two weeks post-transfer. Personality was included as a potential moderator of affective responses. Additionally, expression of tumor necrosis factor alpha (TNF-α), an immunological marker often elevated in clinical depression in humans and animal models, was quantified. Anhedonia was assessed using a palatable food consumption test (sweetcorn) conducted for 5 days before and 5 days after transfer. Low mood was assessed through an attention bias test. Personality was evaluated using four behavioral assays (open field, novel object, stationary human, and tonic immobility tests). A composite Affective Index was also calculated by integrating the behavioral measures of anhedonia and low mood into a single outcome variable. TNF-α expression was measured at baseline (pre-transfer) and 80 days post-transfer. Battery-caged hens exhibited behavioral indicators consistent with depression-like states during the first two weeks after transfer, including reduced sweetcorn intake and increased attention to threat, particularly among more fearful individuals. The Affective Index corroborated that battery-housed hens experienced more negative affective states overall, with fearful individuals being especially vulnerable. Contrary to predictions, TNF-α expression decreased in caged hens 80 days post-transfer, possibly reflecting immunosuppression due to chronic stress. These findings highlight that conventional rearing systems used in egg production can trigger depression-like states in these animals. These results support the need to critically review housing conditions in commercial production systems and to promote management strategies that minimize suffering, especially in vulnerable individuals.

Environmental enrichment is widely used to enhance the welfare of captive animals, particularly in cognitively complex species such as parrots. This study experimentally evaluated the behavioral effects of two enrichment categories: object-based items and food-based enrichment on captive cockatiels (Nymphicus hollandicus). Forty adult birds were observed across three phases: a 30-day baseline without enrichment (March–April 2023), followed by a 30-day acclimatization period (May 2023), a 30-day enrichment phase (June–July 2023), and a post-enrichment phase after a 30-day latency (September–October 2023). Behavioral data were collected through focal animal sampling and analyzed using generalized linear mixed models. Enrichment reduced stress-related behaviors, with a 58 % decrease in FDB directed to conspecifics (IRR = 0.42, p < 0.001) and a 43 % decrease in self-directed FDB (IRR = 0.57, p = 0.034). While FDB directed to conspecifics reductions persisted post-enrichment, the effect on self-directed FDB did not. Positive behaviors also increased, with greater flight activity during enrichment (IRR = 1.43, p < 0.001) and a significant rise in mating behavior in the post-enrichment phase (IRR = 2.27, p = 0.021). Object-based enrichment items elicited significantly more engagement than food-based ones (p < 0.001). Interindividual variation was notable. Cluster analysis revealed distinct behavioral profiles, ranging from highly responsive to non-responsive individuals. These results reveal substantial interindividual variation, suggesting that birds differ in their responsiveness to enrichment. Overall, enrichment reduced stress-related behaviors and promoted behavioral flexibility, as evidenced by the capacity of individuals to adjust their activity patterns in response to changing environmental conditions. These findings support the use of tailored enrichment protocols to enhance the welfare of captive psittacines.

Animal Welfare InstituteRefinement Database

Welcome to the Refinement Database

Search scientific articles, books, and other publications related to improving or safeguarding the welfare of animals used in research and testing.

Active Filters

Search Results

Affective and behavioural interactions between human handlers and laboratory rats (2026)

Analgesic efficacy of oral tramadol–dipyrone combination in cats undergoing ovariohysterectomy (2026)

Anesthetic management and complications during transvenous pacemaker implantation in dogs (2026)

Automated, stress-free, and precise measurement of songbird weight in neuroscience experiments (2026)

Behaviour and spatial distribution of rainbow trout (Oncorhynchus mykiss) in experimental tanks: Influence of water flow and husbandry procedures (2026)

Biopierces: Drug-eluting ear tags for infection prevention in animal tagging (2026)

Comparison of analgesic efficacy between intrafunicular and intratesticular lidocaine injection in dogs (2026)

Developing and validating a holistic welfare assessment tool for zoo-housed great apes: Integrating resource-based measures with behavioural ecology insights (2026)

Effects of hand-rearing and group size on chimpanzee (Pan troglodytes) social competence in captivity (2026)

Effects of housing and environmental enrichment on performance, welfare, and air quality in fattening pigs (2026)

Effects of natural and artificial shade on behavior, physiology, and productivity in water buffalo: A narrative review (2026)

Effects of pen partition design and hiding facilities on elimination and lying behavior of finishing pigs (2026)

Effects of social pairing on measurable disease outcomes in hospitalized rhesus macaques (Macaca mulatta) (2026)

Efficacy and adverse effects of three delivery methods for aerosolized salbutamol in anesthetized European moose (Alces alces alces): A case series (2026)

Efficacy of warmed inspired air for prevention of perianesthetic hypothermia in New Zealand white rabbits (Oryctolagus cuniculus) (2026)

Environmental downgrading to battery cages induces depression-like states in hens (2026)

Environmental enrichment improves behavior and welfare in captive cockatiels (2026)

EPI-DOM framework for fish welfare assessment: External and internal indicators for tilapia in aquaculture (2026)

Ethological constraints and welfare-related bias in laboratory mice: Implications of housing, lighting, and social environment (2026)

Euthanasia methods in invertebrates: A critical narrative review of methodological and welfare standards (2026)

Welcome to the Refinement Database

Search scientific articles, books, and other publications related to improving or safeguarding the welfare of animals used in research and testing.

Filter by Animal Type

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Search Results

Affective and behavioural interactions between human handlers and laboratory rats (2026)

Analgesic efficacy of oral tramadol–dipyrone combination in cats undergoing ovariohysterectomy (2026)

Anesthetic management and complications during transvenous pacemaker implantation in dogs (2026)

Automated, stress-free, and precise measurement of songbird weight in neuroscience experiments (2026)

Behaviour and spatial distribution of rainbow trout (Oncorhynchus mykiss) in experimental tanks: Influence of water flow and husbandry procedures (2026)

Biopierces: Drug-eluting ear tags for infection prevention in animal tagging (2026)

Comparison of analgesic efficacy between intrafunicular and intratesticular lidocaine injection in dogs (2026)

Developing and validating a holistic welfare assessment tool for zoo-housed great apes: Integrating resource-based measures with behavioural ecology insights (2026)

Effects of hand-rearing and group size on chimpanzee (Pan troglodytes) social competence in captivity (2026)

Effects of housing and environmental enrichment on performance, welfare, and air quality in fattening pigs (2026)

Effects of natural and artificial shade on behavior, physiology, and productivity in water buffalo: A narrative review (2026)

Effects of pen partition design and hiding facilities on elimination and lying behavior of finishing pigs (2026)

Effects of social pairing on measurable disease outcomes in hospitalized rhesus macaques (Macaca mulatta) (2026)

Efficacy and adverse effects of three delivery methods for aerosolized salbutamol in anesthetized European moose (Alces alces alces): A case series (2026)

Efficacy of warmed inspired air for prevention of perianesthetic hypothermia in New Zealand white rabbits (Oryctolagus cuniculus) (2026)

Environmental downgrading to battery cages induces depression-like states in hens (2026)

Environmental enrichment improves behavior and welfare in captive cockatiels (2026)

EPI-DOM framework for fish welfare assessment: External and internal indicators for tilapia in aquaculture (2026)

Ethological constraints and welfare-related bias in laboratory mice: Implications of housing, lighting, and social environment (2026)

Euthanasia methods in invertebrates: A critical narrative review of methodological and welfare standards (2026)