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. 
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...

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...

Cohen, S., Kwok, M., Huang, J. 2020. Humane euthanasia of guinea pigs (Cavia porcellus) with a penetrating spring-loaded captive bolt. Animals 10(8), 1356.

Guinea pigs (Cavia porcellus) have been used in research since the 19th century to collect data due to their physiological similarities to humans. Today, animals perform a vital role in experiments and concerns for laboratory...

Cortese, M., Brščić, M., Ughelini, N. et al. 2020. Effectiveness of stocking density reduction on mitigating lameness in a Charolais finishing beef cattle farm. Animals 10(7), 1147.

This study aimed at assessing whether a reduction in stocking density (SKD) would mitigate lameness and positively affect the performance and health of Charolais bulls in an Italian commercial farm. Bulls were distributed in groups...

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...

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...

Lutz, J., Burla, J.-B., Gygax, L. et al. 2019. Horned and dehorned dairy cows differ in the pattern of agonistic interactions investigated under different space allowances. Applied Animal Behaviour Science 218, 104819.

Limited space in dairy cattle farming is associated with frequent encounters between cows, often resulting in agonistic interactions and injuries, especially in horned cows. Previous studies with dairy cows investigated space allowances in the waiting...

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...

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...

Gilliam, J. N., Woods, J., Hill, J. et al. 2018. Evaluation of the CASH Dispatch Kit combined with alternative shot placement landmarks as a single-step euthanasia method for cattle of various ages. Animal Welfare 27(3), 225-233.

Humane euthanasia of cattle under field conditions presents special challenges for veterinarians and producers. The purpose of this study was to evaluate the effectiveness of the CASH Dispatch Kit captive-bolt system combined with improved shot...

Golledge, H., Carter, E. 2018. Welfare of fish farmed in the EU during transport and at slaughter. Animal Welfare 27(3), 287-288.

This Report, commissioned by the European Commission, summarises the current state of transport and slaughter practices in the aquaculture industry within eleven case-study countries in the European Economic Area (EAA). Comparisons are also made with...

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...

Shearer, J. 2018. Euthanasia of cattle: Practical considerations and application. Animals 8(4), 57.

Acceptable methods for the euthanasia of cattle include overdose of an anesthetic, gunshot and captive bolt. The use of anesthetics for euthanasia is costly and complicates carcass disposal. These issues can be avoided by use...

Hickman D. L. 2018. Interpreting neuroendocrine hormones, corticosterone, and blood glucose to assess the wellbeing of anesthetized rats during euthanasia. JAALAS 57(6), 725–728.

Current recommendations for assessing animal wellbeing during euthanasia suggest that measuring neuroendocrine hormones—such as ACTH, noradrenaline, and adrenaline—is preferable to measuring corticosterone and blood glucose because of the sensitivity of neuroendocrine hormones to the acute...

Hickman D. L. 2018. Home cage compared with induction chamber for euthanasia of laboratory rats. JAALAS 57(6), 729–733.

This study compared behavioral and physiologic changes in Sprague–Dawley and Brown Norway rats that were euthanized by using a 30% volume displacement rate of CO2 in either their home cage or an induction chamber; rats...

Witaifi, A. A., Ali, A. B. A., Siegford, J. M. 2018. Stall and feed bunk stocking rates impact cows' diurnal behavior and activity in automatic milking system farms. Journal of Veterinary Behavior 24, 48-55.

High stall stocking rates have been shown to alter behavior of cows in parlor-milked systems; however, no studies have examined stocking rates for cows milked with automatic milking systems (AMSs). Therefore, we examined the influence...

Barker, T. H., George, R. P., Howarth, G. S. et al. 2017. Assessment of housing density, space allocation and social hierarchy of laboratory rats on behavioural measures of welfare. PLOS ONE 12(9), e0185135.

Minimum space allowances for laboratory rats are legislated based on weight and stocking rates, with the understanding that increased housing density encourages crowding stress. However, there is little evidence for these recommendations, especially when considering...

Schiffer, K. J., Retz, S. K., Algers, B. 2017. Assessment of stun quality after gunshot used on cattle: a pilot study on effects of diverse ammunition on physical signs displayed after the shot, brain tissue damage and brain haemorrhages. Animal Welfare 26(1), 95-109.

Moving the slaughter process from the abattoir to the animals' familiar environment has the potential to reduce pre-mortal stressors to a minimum and contribute considerably to improved animal welfare at slaughter. On-farm stunning and killing...

Pinelli, C., Leri, F., Turner, P. 2017. Long term physiologic and behavioural effects of housing density and environmental resource provision for adult male and female Sprague Dawley rats. Animals 7(6), 44.

There is considerable interest in refining laboratory rodent environments to promote animal well-being, as well as research reproducibility. Few studies have evaluated the long term impact of enhancing rodent environments with resources and additional cagemates...

Boivin, G. P., Hickman, D. L., Creamer-Hente, M. A. et al. 2017. Review of CO2 as a euthanasia agent for laboratory rats and mice. JAALAS 56(5), 491-499.

Selecting an appropriate, effective euthanasia agent is controversial. Several recent publications provide clarity on the use of CO2 in laboratory rats and mice. This review examines previous studies on CO2 euthanasia and presents the current...

Flint, M., Mills, P. C., Loban, F. et al. 2017. Development of a humane slaughter device for green turtles for use by traditional owners in the Torres Strait Islands, Australia. PLOS ONE 12(1), e0167849.

Marine turtles are caught and slaughtered for consumption as part of traditional indigenous community harvest in Australia as well as in many countries in which marine turtles can be found. However, changes to the Animal...

Bermejo-Poza, R., De la Fuente, J., Pérez, C. 2016. Reducing the effect of pre-slaughter fasting on the stress response of rainbow trout (Oncorhynchus mykiss). Animal Welfare 25(3), 339-346.

Fasting is commonly used in aquaculture to empty the gut before slaughter, but little is known about how feeding frequency before fasting affects the stress response of trout. To find out more, 240 rainbow trout...