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. 
Cox, R. J., Nol, P., Ellis, C. K. et al. 2019. Research with agricultural animals and wildlife. ILAR Journal 60(1), 66-73.

In fiscal year 2016, agricultural animals such as swine, sheep, goats, and cattle represented 10% of the 820 812 animals used in USDA-regulated research. In addition to traditional agricultural animals, research studies using captive wildlife...

Kells, N. J., Beausoleil, N. J., Sutherland, M. A. et al. 2018. Electroencephalographic responses of anaesthetised pigs to intraperitoneal injection of sodium pentobarbital. Animal Welfare 27(3), 205-214.

Small laboratory animals are commonly euthanased via intraperitoneal (IP) injection of sodium pentobarbital. However, there is concern that animals may experience pain prior to loss of consciousness with this delivery route. The present study investigated...

Maigrot, A., Hillmann, E., Briefer, E. 2018. Encoding of emotional valence in wild boar (Sus scrofa) calls. Animals 8(6), 85.

Measuring emotions in nonhuman mammals is challenging. As animals are not able to verbally report how they feel, we need to find reliable indicators to assess their emotional state. Emotions can be described using two...

Grist, A., Lines, J., Knowles, T. et al. 2018. The use of a non-penetrating captive bolt for the euthanasia of neonate piglets. Animals 8(4), 48.

The most common method for the on-farm euthanasia of neonate piglets is reported to be manual blunt force trauma. This paper presents the results of research to evaluate a mechanical non-penetrating captive bolt (the Accles...

Grist, A., Lines, J., Knowles, T. et al. 2018. The use of a mechanical non-penetrating captive bolt device for the euthanasia of neonate lambs. Animals 8(4), 49.

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 lambs (Ovis aries) of 4.464 kg (SD...

Smith, R., Rault, J., Gates, R. et al. 2018. A two-step process of nitrous oxide before carbon dioxide for humanely euthanizing piglets: On-farm trials. Animals 8(4), 52.

Current methods of euthanizing piglets are raising animal welfare concerns. Our experiment used a novel two-step euthanasia method, using nitrous oxide (N2O) for six minutes and then carbon dioxide (CO2) on compromised 0- to 7-day-old...

Kells, N., Beausoleil, N., Johnson, C. et al. 2018. Evaluation of different gases and gas combinations for on-farm euthanasia of pre-weaned pigs. Animals 8(3), 40.

The aim of this research was to evaluate the welfare of pre-weaned piglets euthanised using three different gas treatments: 100% carbon dioxide (CO2), 100% argon (Ar) or a mixture of 60% Ar/40% carbon dioxide (Ar/CO2)...

Backus, B. L., McGlone, J. J. 2018. Evaluating environmental enrichment as a method to alleviate pain after castration and tail docking in pigs. Applied Animal Behaviour Science 204, 37-42.

Castration and tail docking are common management practices performed on commercial swine farms in the US and around the world to reduce adverse behaviors and the occurrence of boar taint. However, these practices themselves are...

Grist, A., Knowles, T. G., Wotton, S. B. 2018. Humane euthanasia of neonates II: field study of the effectiveness of the Zephyr EXL non-penetrating captive-bolt system for euthanasia of newborn piglets. Animal Welfare 27(4), 319-326.

A previous study demonstrated the effectiveness of the Bock Industries Zephyr EXL non-penetrating captive bolt, using the abolition of visual-evoked potentials as a determination of brain death, in piglets in a laboratory. A second trial...

Mason, A., Tolo, E., Hektoen, L. et al. 2018. The effect of electrical head-to-chest stunning on the EEG in sheep. Animal Welfare 27(4), 343-350.

Head-to-body stunning is regarded as ‘best practice’ stunning for sheep. The benefits are loss of consciousness followed by cardiac arrest, death, prevention of animal movements post stun/kill and improved meat quality. Commercial equipment places electrodes...

Straticò, P., Varasano, V., Suriano, R. et al. 2018. Analgesic effects of intravenous flunixin and intrafunicular lidocaine or their combination for castration of lambs. Veterinary Record Open 5(1), e000266.

Objective: To analyse the effectiveness of intrafunicular lidocaine and intravenous flunixin for reducing pain and signs of stress in lambs undergoing surgical castration. Design: Randomised controlled trial. Setting: One university teaching hospital in Italy. Participants...

Sutherland, M. A., Bryer, P. J., Backus, B. L. 2017. The effect of age and method of gas delivery on carbon dioxide euthanasia of pigs. Animal Welfare 26(3), 293-299.

The objectives of this research were to evaluate the effect of age and delivering method during carbon dioxide (CO2) euthanasia on the welfare of pigs (Sus scrofa). In Experiment 1, pigs aged 1, 2, 3...

Grist, A., Murrell, J. C., McKinstry, J. L. et al. 2017. Humane euthanasia of neonates I: validation of the effectiveness of the Zephyr EXL non-penetrating captive-bolt euthanasia system on neonate piglets up to 10.9 kg live-weight. Animal Welfare 26(1), 111-120.

To determine if mechanical blunt force trauma using a non-penetrating captive bolt was a viable method of producing an immediate stun/kill in neonate piglets (Sus scrofa domesticus) as an alternative to manual blunt force trauma...

Walsh, J., Percival, A., Turner, P. 2017. Efficacy of blunt force trauma, a novel mechanical cervical dislocation device, and a non-penetrating captive bolt device for on-farm euthanasia of pre-weaned kits, growers, and adult commercial meat rabbits. Animals 7(12), 100.

The commercial meat rabbit industry is without validated on-farm euthanasia methods, potentially resulting in inadequate euthanasia protocols. We evaluated blunt force trauma (BFT), a mechanical cervical dislocation device (MCD), and a non-penetrating captive bolt device...

Nordquist, R., van der Staay, F., van Eerdenburg, F. et al. 2017. Mutilating procedures, management practices, and housing conditions that may affect the welfare of farm animals: Implications for welfare research. Animals 7(2), 12.

A number of mutilating procedures, such as dehorning in cattle and goats and beak trimming in laying hens, are common in farm animal husbandry systems in an attempt to prevent or solve problems, such as...

Leliveld, L. M. C., Düpjan, S., Tuchscherer, A. et al. 2017. Vocal correlates of emotional reactivity within and across contexts in domestic pigs (Sus scrofa). Physiology & Behavior 181, 117-126.

Vocalizations have long been recognized to encode information about an individual's emotional state and, as such, have contributed to the study of emotions in animals. However, the potential of vocalizations to also encode information about...

McMillan, J. L., Bloomsmith, M. A., Prescott, M. J. 2017. An international survey of approaches to chair restraint of nonhuman primates. Comparative Medicine 67(5), 442–451.

Specifically designed restraint chairs are the preferred method of restraint for research studies that require NHP to sit in place for sustained periods of time. In light of increasing emphasis on refinement of restraint to...

Sutherland, M. A., Backus, B. L., Brooks, T. A. 2017. The effect of needle-free administration of local anesthetic on the behavior and physiology of castrated pigs. Journal of Veterinary Behavior 21, 71-76.

Pigs are routinely castrated in many countries without giving pain relief, which is an animal welfare concern. The objectives of this study were to evaluate the stress caused by administering local anesthetic (LA) using a...

Hothersall, B., Whistance, L., Zedlacher, H. et al. 2016. Standardising the assessment of environmental enrichment and tail-docking legal requirements for finishing pigs in Europe. Animal Welfare 25(4), 499-515.

An online training package providing a concise synthesis of the scientific data underpinning EU legislation on enrichment and tail-docking of pigs was produced in seven languages, with the aim of improving consistency of professional judgements...

Orford, F., Ford, E. A., Brown, S. N. et al. 2016. The evaluation of two commercial electric sheep stunning systems: current applied and the effect on heart function. Animal Welfare 25(3), 331-337.

The maintenance of head-only minimum stunning currents for sheep to ≥ 1.0 Amp as per current legislation was examined in two trials in a commercial abattoir. In the first trial, a Jetco MS100 stunner failed...

Rodríguez, P., Dalmau, A., Manteca, X. et al. 2016. Assessment of aversion and unconsciousness during exposure to carbon dioxide at high concentration in lambs. Animal Welfare 25(1), 73-82.

The most widely used stunning method in sheep is electrical. However, in lambs, this method leads to rupture of the blood vessels, provoking ecchymoses. In pigs (Sus scrofa), the use of CO2-stunning systems has increased...

Fiedler, K. J., Parsons, R. L., Sadler, L. J. et al. 2016. Effects of stocking rate on measures of efficacy and welfare during argon gas euthanasia of weaned pigs. Animal Welfare 25(1), 83-89.

The objective of this study was to evaluate the effects of chamber stocking rate on facets of animal welfare and efficacy during euthanasia of weaned pigs (Sus scrofa domesticus) with argon gas. Two hundred and...

Wallgren, T., Westing, R., Gunnarsson, S. 2016. A survey of straw use and tail biting in Swedish pig farms rearing undocked pigs. Acta Veterinaria Scandinavica 58(1), 84.

Tail biting is a common problem in intensive pig farming, affecting both welfare and production. Although routine tail docking is banned within the EU, it remains a common practice to prevent tail biting. Straw as...

Goumon, S., Špinka, M. 2016. Emotional contagion of distress in young pigs is potentiated by previous exposure to the same stressor. Animal Cognition 19(3), 501–511.

This study tested whether emotional contagion occurs when piglets directly observe a penmate in distress (restraint) and whether there is an effect of previous experience on the response to subsequent restraint or exposure to conspecific...

Holinger, M., Fruh, B., Hillmann, E. 2015. Group composition for fattening entire male pigs under enriched housing conditions - Influences on behaviour, injuries and boar taint compounds. Applied Animal Behaviour Science 165, 47-56.

In organic farming, the production of pork from entire male pigs seems to be the most promising alternative to castration, as organic animal husbandry aims at high standards of animal welfare and elimination of mutilations...