Refinement Database

Database on Refinement of Housing, Husbandry, Care, and Use of Animals in Research

This database, created in 2000, is updated every four months with newly published scientific articles, books, and other publications related to improving or safeguarding the welfare of animals used in research.

Tips for using the database:

  • This landing page displays all of the publications in the database.
  • Use the drop-down menus to filter these publications by Animal Type, Setting, and/or Topic.
  • Clicking on a parent category (e.g., Rodent) will include publications relating to all the items in that category (e.g., Chinchilla, Gerbil, Guinea Pig, etc.).
  • You may also add a keyword to further narrow your search.
  • Please note that at this time, only publications dated 2010 or later (with some exceptions) can be filtered by Animal Type and Topic, and only publications dated 2020 or later (with some exceptions) can be filtered by Setting. Most publications older than 2010 can only be searched by keyword. 
Hickman, D. L. 2022. Minimal exposure times for irreversible euthanasia with carbon dioxide in mice and rats. JAALAS 61(3), 283-286.

When using an anesthetic overdose to euthanize laboratory rodents, a secondary method of euthanasia is recommended to ensure that the apparent death is irreversible. This secondary method usually is accomplished through the collection of tissues...

McKinney, M. M., Dupont, W. D., Corson, K. J. et al. 2022. Physiologic and behavioral effects in mice anesthetized with isoflurane in a red-tinted or a traditional translucent chamber. JAALAS 61(4), 322-332.

Isoflurane has been characterized as a distressing agent for rodents, causing both physiologic and behavioral effects. Using a "darkened home cage" has been recommended during CO2 administration for rodent euthanasia; this is arguably a similar...

Neto, T., Faustino-Rocha, A. I., Gil da Costa, R. M. et al. 2022. A quick and low-intensity method for oral administration to large numbers of mice: A possible alternative to oral gavage. Laboratory Animals 56(2), 185-190.

Oral administration of medication to experimental animals is a cause of significant stress. When coupled to animals who are already under strenuous circumstances due to the disease being modelled, there is a significant risk for...

Scariot, P. P., Gobatto, C. A., Polisel, E. E. et al. 2022. Early-life mice housed in standard stocking density reduce the spontaneous physical activity and increase visceral fat deposition before reaching adulthood. Laboratory Animals 56(4), 344-355.

Laboratory rodents spend the entire day housed in standard cages that provide a restricted area for movements and might, therefore, limit physical activity. However, it has not been tested in immature rodents of ages ranging...

Clarkson, J. M., Martin, J. E., McKeegan, D. E. F. 2022. A review of methods used to kill laboratory rodents: Issues and opportunities. Laboratory Animals 56(5), 419-436.

Rodents are the most widely used species for scientific purposes. A critical pre-requisite of their use, based on utilitarian ethical reasoning, is the provision of a humane death when necessary for scientific or welfare grounds...

Tetlow, S. A. J., Brennan, M. L., Garcia-Ara, A. 2022. Welfare indicators for stunning versus non-stunning slaughter in sheep and cattle: A scoping review. Vet Record 191(6), e1739.

Background: While most cattle and sheep in the United Kingdom are stunned before slaughter, non-stun methods are permitted to supply meat to specific consumers. This study aimed to identify the existing literature that compared animal...

Li, W., Yan, C., Descovich, K. et al. 2022. The effects of preslaughter electrical stunning on serum cortisol and meat quality parameters of a slow-growing Chinese chicken breed. Animals 12(20), 2866.

Electrical stunning is widely utilized prior to a neck cut to induce unconsciousness in order to improve animal welfare and slaughter efficiency in the broiler production industry. However, slaughter without stunning is still very commonly...

Mayes, B. T., Tait, L. A., Cowley, F. C. et al. 2022. Stocking density, restricted trough space, and implications for sheep behaviour and biological functioning. Frontiers in Veterinary Science 9, 965635.

Stocking density and trough space allowance can potentially impact sheep welfare during live export voyages. The aim of this study was to assess the welfare implications for sheep housed at five allometric stocking densities, with...

Schwarzer, A., Erhard, M., Schmidt, P. et al. 2022. Effects of stocking rate and environmental enrichment on the ontogeny of pecking behavior of laying hen pullets confined in aviary compartments during the first 4 weeks of life. Animals 12(19), 2639.

The objective of this study was to describe the ontogeny of the severe feather pecking (SFP), gentle feather pecking (GFP), aggressive pecking (AP), and enrichment pecking (EP) of non-beak-trimmed Lohmann Brown (LB)-pullets during the first...

Wahltinez, S. J., Stacy, N. I., Hadfield, C. A. et al. 2022. Perspective: Opportunities for advancing aquatic invertebrate welfare. Frontiers in Veterinary Science 9, 973376.

Welfare considerations and regulations for invertebrates have lagged behind those for vertebrates, despite invertebrates comprising more than 95% of earth’s species. Humans interact with and use aquatic invertebrates for exhibition in zoos and aquaria, as...

van der Eijk, J. A. J., Gunnink, H., Melis, M. et al. 2022. Reducing stocking density benefits behaviour of fast- and slower-growing broilers. Applied Animal Behaviour Science 257, 105754.

The broiler industry has come under sustained pressure from welfare organizations to improve broiler welfare. Breed and stocking density are important factors for broiler welfare and are often specified as criteria for higher welfare systems...

Hepps Keeney, C., Harrison, T. M. 2022. Euthanasia complications in non-domestic species. Journal of Zoological and Botanical Gardens 3(4), 616–623.

There are very few studies describing euthanasia complications in non-domestic species. The goal of this study was to survey veterinarians to determine what complications may commonly occur during the euthanasia of non-domestic species. An online...

Wotton, S., Grist, A., O’Callaghan, M. et al. 2021. Head-only stunning of turkeys Part 2: Subjective and objective assessment of the application of AC and DC waveforms. Animals 11(2), 286.

Electrical stunning is likely to remain an important stunning method for turkeys at slaughter. The purpose of this study is to understand the application of various waveforms of alternating current (AC) and pulsed direct currents...

Hickman, D. L. 2021. Wellbeing of mice euthanized with carbon dioxide in their home cage as compared with an induction chamber. JAALAS 60(1), 72-76.

The AVMA Guidelines on Euthanasia state that, to decrease potential distress of animals, the home cage should be used for the euthanasia of mice. The current study evaluated this recommendation by comparing behavioral and physiologic...

Schalbetter, S. M., Mueller, F. S., Scarborough, J. et al. 2021. Oral application of clozapine-N-oxide using the micropipette-guided drug administration (MDA) method in mouse DREADD systems. Lab Animal 50, 69-75.

The designer receptor exclusively activated by designer drugs (DREADD) system is one of the most widely used chemogenetic techniques to modulate the activity of cell populations in the brains of behaving animals. DREADDs are activated...

Teixeira-Santos, L., Albino-Teixeira, A., Pinho, D. 2021. An alternative method for oral drug administration by voluntary intake in male and female mice. Laboratory Animals 55(1), 76-80.

Drug administration to experimental rodents is often invasive and stressful, thus reducing animal welfare and potentially confounding experimental results. Methods of oral drug delivery in which rodents cooperate voluntarily minimize stress, pain and morbidity. We herein...

Funkhouser, J. A., Mayhew, J. A., Mulcahy, J. et al. 2021. Human caregivers are integrated social partners for captive chimpanzees. Primates 62(2), 297–309.

In a captive environment, it is challenging to ensure the highest level of social and psychological well-being for species with naturally complex social organizations and structures. There is a growing need to meet the social...

Chaumont, S., Freitas-de-Melo, A., Pinto-Santini, L., Menant, O. et al. 2021. Rams recognize and prefer the human who regularly brushed them. Applied Animal Behaviour Science 236, 105250.

Brushing produces a relaxing effect and improves the welfare of ewes and lambs and the human-animal relationship. Lambs gently handled during rearing are less fearful to humans in their adulthood, but there are few studies...

Sørensen, D., Cloutier, S., Gaskill, B. (Eds.). 2021. Animal-centric Care and Management - Enhancing Refinement in Biomedical Research. CRC Press, Boca Raton, FL.

The concept of the 3Rs (Refinement, Reduction and Replacement) has been used as a framework for improving the welfare of laboratory animals for the last half century. By establishing an animal-centric view on housing and...

Stevens, C., Hawkins, P., Smulders, T. V. et al. 2021. Report of the 2020 RSPCA/UFAW rodent and rabbit welfare meeting. Animal Technology and Welfare 20(1), 21-33.

The RSPCA/UFAW rodent and rabbit welfare group has held a one-day meeting every autumn for the last 27 years, so that its members can discuss current welfare research, exchange views on welfare issues and share...

Phillips, H. N., Heins, B. J. 2021. Effects of outdoor stocking density on growth, feather damage and behavior of slow-growing free-range broilers. Animals 11(3), 688.

Access to pasture is a main benefit of free-range broiler housing systems, yet the level of outdoor stocking density on broiler animal welfare remains unsettled. The growth, feather damage, pasture ranging and behaviors were assessed...

Wilson-Welder, J. H., Frank, A. T. 2021. Use of food enrichment for medication delivery in large groups of sheep. Laboratory Animal Science Professional 9(3) (May/June), 40-43.

In a 2018 AALAS webinar on Sheep and Goat Analgesia, Dr. Susie Vogel, a small ruminant expert, introduced the concept of getting sheep and goats to willingly take medication by putting it in a tasty...

Anderson, M. G., Campbell, A. M., Crump, A. et al. 2021. Effect of environmental complexity and stocking density on fear and anxiety in broiler chickens. Animals 11(8), 2383.

Barren housing and high stocking densities may contribute to negative affective states in broiler chickens, reducing their welfare. We investigated the effects of environmental complexity and stocking density on broilers’ attention bias (measure of anxiety)...

Rodriguez-Sanchez, R., Barnaby, E., Améndola, L. et al. 2021. Voluntary oral ingestion of a sedative prior to euthanasia with CO2: Behavioural responses of mice. Animals 11(10), 2879.

Laboratory mice are commonly euthanised with carbon dioxide (CO2); however, there is ample evidence that this gas is aversive. Previous work suggests that sedation achieved via injection with benzodiazepines prior to CO2 administration could reduce...

Forslind, S., Blokhuis, H. J., Riber, A. B. 2021. Disturbance of resting behaviour of broilers under different environmental conditions. Applied Animal Behaviour Science 242, 105425.

Resting behaviours make up a large part of the daily time budget of broilers. However, in intensive broiler production systems disruptions of resting behaviours occur, where resting individuals get disturbed by active individuals. Such interruptions...