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. 
Frost, K., Shah, M., Leung , V. S. Y. et al. 2020. Aversion to desflurane and isoflurane in Sprague-Dawley rats (Rattus norvegicus). Animals 10(6), 950.

Carbon dioxide and isoflurane are widely used for killing rats, yet may not truly achieve “euthanasia”, because they elicit aversion. The inhalant anesthetic desflurane is faster acting than isoflurane, representing a potential refinement. Using an...

Ballantine, A., Rodgers, D., Watts, C. et al. 2020. The cotton rat – a new challenge. Animal Technology and Welfare 19(1), 92-95.

This poster describes how the Animal Technologists at Envigo adapted their current practices and procedures for a new species at their laboratory: the cotton rat. The paper describes cotton rat biology and behaviour; housing; environmental...

Améndola, L., Weary, D. M. 2020. Understanding rat emotional responses to CO2. Translational Psychiatry 10, 253.

The aim of this review is to summarize evidence regarding rat emotional experiences during carbon dioxide (CO2) exposure. The studies reviewed show that CO2 exposure is aversive to rats, and that rats respond to CO2...

Turner, P. V., Hickman, D. L., van Luijk, J. et al. 2020. Welfare impact of carbon dioxide euthanasia on laboratory mice and rats: A systematic review. Frontiers in Veterinary Science 7, 411.

Background: There has been increased concern about the suitability of CO2 as a method for euthanasia of laboratory mice and rats, including the potential discomfort, pain or distress that animals may experience prior to loss...

Reinhardt, V. (ed.) 2020. It’s Okay to Cry - Discussions by the Laboratory Animal Refinement & Enrichment Forum [LAREF], Volume V. Animal Welfare Institute, Washington, DC.

This is the 5th volume of selected discussions that took place on the electronic Laboratory Animal Refinement & Enrichment Forum between February 2016 and December 2019. The forum was created in October 2002; it allows...

Michaels, C. J., Gini, B. F., Clifforde, L. 2020. A persistent abnormal repetitive behaviour in a false water cobra (Hydrodynastes gigas). Animal Welfare 29(4), 371-378.

Stereotypies (a subset of Abnormal Repetitive Behaviour [ARB]) are characterised by an unchanging pattern of behaviour and in captive animals can be associated with poor welfare. Although well known in certain taxa, little is known...

Shomer, N. H., Allen-Worthington, K. H., Hickman, D. L. et al. 2020. Review of rodent euthanasia methods. JAALAS 59(3), 242–253.

The optimal choice of euthanasia method for laboratory rodents depends on a number of factors, including the scientific goals of the study, the need to minimize animal pain and/or distress, applicable guidelines and laws, the...

Laferriere, C. A., Pang, D. S. 2020. Review of intraperitoneal injection of sodium pentobarbital as a method of euthanasia in laboratory rodents. JAALAS 59(3), 254–263.

Euthanasia is one of the most commonly performed procedures in biomedical research, involving tens of millions of animals in North America and Europe every year. The use of sodium pentobarbital, injected intraperitoneally, for killing rodents...

Szymczyk, K., Gabriel, S., Zegre Cannon, C. 2020. Removing the blindfold in blind intubation: A summary of tips and tricks for successful rabbit intubation. Laboratory Animal Science Professional 8(5) (September/October), 76-81.

Intubation in rabbits can be difficult due to their unique anatomical features. Large incisors, long narrow oral cavities, thick tongues, and limited mobility of the temporomandibular joint make laryngeal visualization difficult. It is the hope...

Munari, C., Ponzio, P., Macchi, E. et al. 2020. A multifactorial evaluation of different reproductive rhythms and housing systems for improving welfare in rabbit does. Applied Animal Behaviour Science 230, 105047.

The most widespread reproductive rhythm practiced in rabbit farming is based on artificial insemination (AI) performed at around 11 days pospartum. This approach results in high production rates, but requires high yearly replacement of animals...

Natusch, D. J. D., Aust, P. W., Khadiejah, S. et al. 2020. Behavioral and corticosterone responses to carbon dioxide exposure in reptiles. PLOS ONE 15(10), e0240176.

The use of carbon dioxide (CO2) exposure as a means of animal euthanasia has received considerable attention in mammals and birds but remains virtually untested in reptiles. We measured the behavioral responses of four squamate...

Kulkarni, S., Hickman, D. 2020. Isoflurane and carbon dioxide elicit similar behavioral responses in rats. Animals 10(8), 1431.

Euthanasia in rodents is an ongoing topic of debate due to concerns regarding the aversive nature of gases with anesthetic properties such as carbon dioxide (CO2) and isoflurane. The aim of this study was to...

Van Wijk, H., Haida, D., Duncan, C. et al. 2020. Surgery refinements improve success rates in rat bile collection. Animal Technology and Welfare 19(3), 251-254.

This poster compares the model success rates using 2 different housing regimes during recovery from surgery. Catheters were placed in the bile duct to collect bile; a second catheter was secured into the duodenum where...

Axiak Flammer, S., Eskes, C., Kohler, I. et al. 2019. Alternatives to carbon dioxide—Taking responsibility for humanely ending the life of animals. Animals 9(8), 482.

Carbon dioxide (CO2) is commonly used to kill rodents. However, a large body of research has now established that CO2 is aversive to them. A multidisciplinary symposium organized by the Swiss Federal Food Safety and...

Steiner, A. R., Axiak Flammer, S., Beausoleil, N. J. et al. 2019. Humanely ending the life of animals: Research priorities to identify alternatives to carbon dioxide. Animals 9(11), 911.

The use of carbon dioxide (CO2) for stunning and killing animals is considered to compromise welfare due to air hunger, anxiety, fear, and pain. Despite decades of research, no alternatives have so far been found...

Lee, L. Y., Lee, D., Ryu, H. et al. 2019. Capnography-guided endotracheal intubation as an alternative to existing intubation methods in rabbits. JAALAS 58(2), 240-245.

Rabbits provide a unique challenge for routine endotracheal intubation in clinical practice because of various distinctive anatomic and physiologic features. Many previously proposed methods for endotracheal intubation in rabbits are limited by several factors, including...

Améndola, L., Ratuski, A., Weary, D. M. 2019. Variation in the onset of CO2-induced anxiety in female Sprague Dawley rats. Scientific Reports 9, 19007.

Carbon dioxide (CO2) is commonly used to kill laboratory rats. Rats find CO2 aversive and aversion varies between individuals, indicating that rats vary in CO2 sensitivity. Healthy humans experience feelings of anxiety at concentrations similar...

McMillan, F. D. (ed). 2019. Mental Health and Well-being in Animals (2nd ed). CABI, Wallingford, UK.

This second edition is fully revised, expanded, and comprehensively updated with the most current knowledge about the full array of mental health issues seen in animals. Written by key opinion leaders, internationally-recognized experts and specialists...

Kells, N. J., Beausoleil, N. J., Sutherland, M. A. et al. 2018. Electroencephalographic responses of anaesthetised rats to carbon dioxide inhalation. Animal Welfare 27(3), 215-223.

Exposure to high concentrations of CO2 is a common means of stunning and killing laboratory rodents. However, there is concern regarding the potential for animals to have aversive experiences, such as pain or breathlessness, prior...

Khoo, S. Y.-S., Lay, B. P. P., Joya, J. et al. 2018. Local anaesthetic refinement of pentobarbital euthanasia reduces abdominal writhing without affecting immunohistochemical endpoints in rats. Laboratory Animals 52(2), 152-162.

Sodium pentobarbital is a commonly used agent for euthanizing laboratory rats, however its high pH can cause abdominal discomfort after intraperitoneal injection. Previous studies suggest that the addition of a local anaesthetic may alleviate this...

Costa, R., Sousa, C., Llorente, M. 2018. Assessment of environmental enrichment for different primate species under low budget: A case study. Journal of Applied Animal Welfare Science 21(2), 185-199.

The 2011 European Union Zoo Inquiry presented evidence that most zoos fail to achieve adequate levels of nonhuman animal welfare. Appropriate environmental enrichment (EE) can play a role in the promotion of welfare. However, financial...

Bacon, H. 2018. Behaviour-based husbandry—A holistic approach to the management of abnormal repetitive behaviors. Animals 8(7), 103.

The field of zoo animal welfare science has developed significantly over recent years. However despite this progress in terms of scientific research, globally, zoo animals still face many welfare challenges. Recently, animal welfare frameworks such...

Grist, A., Lines, J., Knowles, T. et al. 2018. Use of a non-penetrating captive bolt for euthanasia of neonate goats. Animals 8(4), 58.

A non-penetrating captive bolt device, powered by a 1 grain 0.22″ cartridge delivering a calculated kinetic energy of 47 Joules was tested as a euthanasia method on 200 neonate goats (Capra aegagrus hircus) of mean...

van Wijk, H., Crossman, L., Adjin-Tettey, G. et al. 2018. Advances in animal welfare and scientific outcomes of the bile duct cannulated rat model utilised in ADME studies. Animal Technology and Welfare 17(1), 64-67.

Since rats lack a gall bladder, they are an ideal model for investigating continuous biliary excretion and biotransformation. The design and implementation of a modified tail cuff and cannula system introduced at Covance permits the...

Wang, R., Hausknechta, K. A., Haj-Dahmane, S. et al. 2018. Decreased environmental complexity during development impairs habituation of reinforcer effectiveness of sensory stimuli. Behavioural Brain Research 337, 53-60.

Previous research has shown that rats reared in simple/impoverished environments demonstrate greater repetitive responding for sensory reinforcers (e.g., light onset). Moreover, the brains of these rats are abnormally developed, compared to brains of rats reared...