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. 
da Silva, A., Lima, M. R., Meletti, P. C. et al. 2020. Impact of environmental enrichment and social group size in the aggressiveness and foraging activity of Serrapinnus notomelas. Applied Animal Behaviour Science 224, 104943.

Fish are widely used in scientific research, and many species are bred for ornamental purposes and human consumption. Despite the large number of fish kept in captivity, research on the welfare of these animals has...

Wang, C., Han, Q., Liu, R. et al. 2020. Equipping farrowing pens with straw improves maternal behavior and physiology of Min-Pig hybrid sows. Animals 10(1), 105.

This study investigated the effects of two factors, enriched environment (EE) and different crossbreeds, on the maternal behavior and physiology of Min-pig hybrid sows. The analysis was performed on a total of 72 multiparous sows...

Zhang, X., Li, C., Hao, Y. et al. 2020. Effects of different farrowing environments on the behavior of sows and piglets. Animals 10(2), 320.

We investigated the effect of different farrowing systems on the behavior of sows and piglets. In total, 22 hybrid sows (Yorkshire × Landrace) were randomly assigned into three farrowing systems, farrowing crate (FC), free farrowing...

Chou, J.-Y., D’Eath, R. B., Sandercock, D. A. et al. 2020. Enrichment use in finishing pigs and its relationship with damaging behaviours: Comparing three wood species and a rubber floor toy. Applied Animal Behaviour Science 224, 104944.

Environmental enrichment in pig housing is a legal requirement under current EU legislation, but some recommended loose materials may cause obstructions in fully-slatted systems. Wood is an organic material that could be compatible with slatted...

de la Garza, F., Cannon, C. Z. 2020. Piggy see, piggy do: A swine training program enhances animal welfare and research. Laboratory Animal Science Professional 8(2) (March/April), 54-57.

Becton Dickinson (BD) Animal Research Program developed an extensive training and environmental enrichment program to acclimate newly arrived swine to daily husbandry routines. The program seeks to build trust between swine and animal care and...

Luo, L., Jansen, C. A., Bolhuis, J. E. et al. 2020. Early and later life environmental enrichment affect specific antibody responses and blood leukocyte subpopulations in pigs. Physiology & Behavior 217, 112799.

This study addressed the impact of early and later life environmental enrichment, and their combination, on specific antibody responses and peripheral blood leukocyte subpopulations in pigs. Pigs were kept in either barren (B1) or enriched...

Crawford, L. E., Knouse, L. E., Kent, M. et al. 2020. Enriched environment exposure accelerates rodent driving skills. Behavioural Brain Research 378, 112309.

Although rarely used, long-term behavioral training protocols provide opportunities to shape complex skills in rodent laboratory investigations that incorporate cognitive, motor, visuospatial and temporal functions to achieve desired goals. In the current study, following preliminary...

Qu, C., Xu, L., Shen, J. et al. 2020. Protection of blood-brain barrier as a potential mechanism for enriched environments to improve cognitive impairment caused by chronic cerebral hypoperfusion. Behavioural Brain Research 379, 112385.

Chronic cerebral hypoperfusion (CCH) is a common pathophysiological basis for Alzheimer’s Disease and vascular dementia in the early stages. It has been confirmed that blood-brain barrier (BBB) destruction is a key factor in CCH-related cognitive...

Menezes, J., Souto das Neves, B.-H., Gonçalves, R. et al. 2020. Maternal deprivation impairs memory and cognitive flexibility, effect that is avoided by environmental enrichment. Behavioural Brain Research 381, 112468.

Maternal deprivation (MD) causes cognitive deficits that persist until adulthood. Thereby, the environmental enrichment (EE) is widely used to increase brain plasticity. Here, pregnant female rats were used and their offspring were submitted to neonatal...

Brown, J. L., Bansiddhi, P., Khonmee, J. et al. 2020. Commonalities in management and husbandry factors important for health and welfare of captive elephants in North America and Thailand. Animals 10(4), 737.

This review paper is a synthesis of results from multiple studies that we have conducted over the past several years using similar methodologies to identify factors related to welfare of captive populations of elephants in...

Çavuşoğlu, E., Rault, J.-L., Gates, R. et al. 2020. Behavioral response of weaned pigs during gas euthanasia with CO2, CO2 with butorphanol, or nitrous oxide. Animals 10(5), 787.

The swine industry is often forced to euthanize pigs in the first few weeks of life due to injuries, hernias, or unthriftiness. The majority of pigs are euthanized using carbon dioxide (CO2) gas asphyxiation but...

Inoue, N., Shimada, M. 2020. Comparisons of activity budgets, interactions, and social structures in captive and wild chimpanzees (Pan troglodytes). Animals 10(6), 1063.

Chimpanzees in zoos with sufficient and appropriate environmental enrichment devices are expected to exhibit behaviors, interactions, and societies similar to those in the wild. In this study, we compared the activity budgets of each observed...

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...

Watson, H. A study into viable wooden enrichment objects for Syrian hamsters. Animal Technology and Welfare 19(1), 86-88.

Failing to provide hamsters with a method to wear down their teeth can lead to detrimental behaviour such as bar chewing, and health issues, for example, overgrown teeth and tooth loss. However, hamsters use their...

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...

Kauselmann, K., Krause, E. T., Glitz, B. et al. 2020. Short-term choice of fattening pigs for additional plant-based materials. Applied Animal Behaviour Science 226, 104975.

A major problem in conventional pig production systems is the occurrence of abnormal behaviours such as tail biting. Tail biting is a multifactorial problem, but it seems that a lack of proper enrichment materials prevents...

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...

Chu, D. 2020. Malawi cichlids: A colorful 4th R story. Laboratory Animal Science Professional 8(3) (May/June), 24-25.

This article describes the successful rehoming of 60 Malawi cichlids from a vivarium at Stanford University to San Diego Zoo and the California Academy of Sciences.

Brekke, J., Scholz, J. 2020. Just hanging out: Elevating rat enrichment in small spaces. Laboratory Animal Science Professional 8(3) (May/June), 40-42.

This article describes how an Animal Care Technician at Mayo Clinic Rochester campus designed and created a novel enrichment item for rats: a ‘hammock’ made of PVC tunnels hung onto the lid of standard laboratory...

Arechavala-Lopez, P., Caballero-Froilán, J. C., Jiménez-García, M. et al. 2020. Enriched environments enhance cognition, exploratory behaviour and brain physiological functions of Sparus aurata. Scientific Reports 10, 11252.

Environmental enrichment is considered as a recommended tool to guarantee or improve the welfare of captive fish. This study demonstrates for the first time that structural environmental enrichment enhances cognition, exploratory behaviour and brain physiological...

Hambrecht, S., Oerke, A.‐K., Heistermann, M. et al. 2020. Diurnal variation of salivary cortisol in captive African elephants (Loxodonta africana) under routine management conditions and in relation to a translocation event. Zoo Biology 39(3), 186–196.

The present study assessed the diurnal variation in salivary cortisol in captive African elephants during routine management (baseline) and in relation to a potential stressor (translocation) to evaluate to what extent acute stress may affect...

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...

Luo, L., Reimert, I., Middelkoop, A. et al. 2020. Effects of early and current environmental enrichment on behavior and growth in pigs. Frontiers in Veterinary Science 7, 268.

Enriched environments are known to beneficially affect the behavior of pigs, as compared with barren pens. The influence of enrichment may, however, depend on pigs' early life housing experiences. The aim of this study was...

Parois, S. P., Duttlinger, A. W., Richert, B. T. et al. 2020. Effects of three distinct 2-week long diet strategies after transport on weaned pigs' short and long-term welfare markers, behaviors, and microbiota. Frontiers in Veterinary Science 7, 140.

Alternative feed supplements have shown promising effects in terms of performance, but their effects on welfare have had little evaluation. In the present study, we aimed at evaluating the effect of diet supplementation on welfare...

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...