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 April 2026.

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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.

Providing nesting material is one of the main forms of environmental enrichment for laboratory mice. Nest building is an innate behavior, widely observed in wild mice, which construct complex, dome-shaped, multi-layered structures. Although various materials can be used in microisolator cage systems, this behavior remains underexplored under laboratory conditions. Evidence indicates that laboratory mice can build nests comparable to those of their wild counterparts, reinforcing the relevance of this enrichment for animal welfare. The aim of this study was to evaluate nest-building behavior in mice, considering biological and environmental variables, including strain, sex, age, nest location within the cage, seasonal variation, ambient temperature, and the use of cardboard tunnels. A total of 620 observations were analyzed from 106 cages, each containing 2–5 mice of both sexes, distributed across three strains (B6J, Nude, and BTBR). Nests were assessed weekly over the course of one year using a scoring system adapted from previous studies, in which higher scores indicate more elaborate, dome-shaped structures, whereas lower scores correspond to incomplete, flat, or less cohesive constructions. The use of cardboard tunnels provided as enrichment was also recorded (intact, shredded, or soiled with excreta). Other variables evaluated included age (20–109 days), and the position and side of the nest within the cage. Most mice built well-structured nests, with 39% of cages reaching the maximum score of 5. Statistical analysis showed that nest quality was significantly influenced by strain, season, and nest location within the cage. Compared to Nude mice, B6J and BTBR strains showed reduced nest-building performance. Scores were lower in spring compared to winter, while nests located at the cage edges, particularly on the right side and at the front, had slightly higher scores than those in the center. In conclusion, strain is the primary determinant of nest quality, while environmental and positional factors exert additional effects. Nude mice, during winter or colder periods, and nests located at the edges and front of the cage were associated with more complex nest constructions.

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.

Rodents are highly susceptible to peri-anesthetic hypothermia because of their small body size, large surface area to volume/mass ratio, and anesthetic-induced thermoregulatory depression. Early heat loss during induction is rapid and can be difficult to reverse, emphasizing the need for simple, reliable warming solutions during anesthetic induction. We designed and validated a low-cost, Arduino-controlled heated induction chamber for mice and evaluated its safety and efficacy in preventing early hypothermia. The device uses proportional integral derivative control to regulate a heated chamber floor. Bench testing quantified warm-up time, steady-state stability, and the temperature offset between the embedded thermistor and surface temperature. In a randomized, paired, repeated-measures design, 10 adult C57BL/6 mice underwent 2 experimental conditions, unheated induction compared with heated induction, followed by a standardized 10-minute anesthetic maintenance phase on a prewarmed, heated surgical monitoring platform. Core body temperature was measured with intraperitoneal radio frequency identification transponders, while rectal temperature and physiologic parameters (peripheral oxygen saturation, heart rate, respiratory rate) were recorded during maintenance. Recovery time was measured from isoflurane discontinuation until the first voluntary movement. The heated chamber reached thermal stability within 10 minutes; at steady state, a constant average surface temperature near 37.5 °C was reliably obtained. During induction, unheated controls showed a rapid decline in core temperature, while during the heated-chamber induction, they maintained normothermia. The control group did not regain baseline temperature until several minutes into the maintenance phase and stabilized at values ∼1 °C lower than those of the heated group. Both groups remained physiologically stable during anesthetic maintenance and recovered within comparable times. This cost-effective, Arduino-based chamber prevented early hypothermia without compromising physiologic stability and represents a practical refinement to improve rodent anesthetic procedures, animal welfare, and experimental reproducibility.

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.

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.

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A collaborative, multi-institutional growth standard for dam-reared infant rhesus and pigtail macaques (Macaca mulatta and Macaca nemestrina) in research settings (2026)

A comparative analysis of the cat stress score and the novel psychological quality of life assessment tool for cats in a shelter setting (2026)

A software based, minimally invasive validated image processing approach for the visualization of blood flow dynamics in mice (2026)

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

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)

Application of minimally invasive physiological monitoring techniques in pigs for scientific purposes (2026)

Assessing laboratory animal welfare: The crucial importance of construct validity (2026)

Assessing local anesthesia in Octopus bimaculoides to provide analgesia (2026)

Assessing nest-building performance in mice: A multifactorial study of strain, age, sex, and environmental factors (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)

Blue light exposure mitigates vibration noise-induced anxiety by enhancing serotonin levels (2026)

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

Cuprizone in peanut butter: An alternative method of cuprizone administration to model demyelination of the central nervous system (2026)

Design and validation of an Arduino-based, cost-effective heated anesthesia induction chamber for mice (2026)

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

Distress calls as social stressors affecting chicken welfare (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.

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Search Results

A collaborative, multi-institutional growth standard for dam-reared infant rhesus and pigtail macaques (Macaca mulatta and Macaca nemestrina) in research settings (2026)

A comparative analysis of the cat stress score and the novel psychological quality of life assessment tool for cats in a shelter setting (2026)

A software based, minimally invasive validated image processing approach for the visualization of blood flow dynamics in mice (2026)

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

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)

Application of minimally invasive physiological monitoring techniques in pigs for scientific purposes (2026)

Assessing laboratory animal welfare: The crucial importance of construct validity (2026)

Assessing local anesthesia in Octopus bimaculoides to provide analgesia (2026)

Assessing nest-building performance in mice: A multifactorial study of strain, age, sex, and environmental factors (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)

Blue light exposure mitigates vibration noise-induced anxiety by enhancing serotonin levels (2026)

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

Cuprizone in peanut butter: An alternative method of cuprizone administration to model demyelination of the central nervous system (2026)

Design and validation of an Arduino-based, cost-effective heated anesthesia induction chamber for mice (2026)

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

Distress calls as social stressors affecting chicken welfare (2026)