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. 
Ayala-Méndez, G. X., Calderón, V. M., Zuñiga-Pimentel, T. A. et al. 2023. Noninvasive monitoring of blood pressure and heart rate during estrous cycle phases in bormotensive Wistar–Kyoto and spontaneously hypertensive female rats. JAALAS 62(3), 267–273.

Since 2015, the National Institutes of Health has called for its funded preclinical research to include both male and female subjects. However, much of the basic animal research that has studied heart rate and blood...

Hickman, D. L. 2023. Euthanasia of neonatal rats and mice using carbon monoxide. JAALAS 62(3), 274–278.

Minimization of potential pain and distress of rodents undergoing euthanasia is a touchstone of veterinary clinical medicine. Evaluation of this issue in postweanling rodents has supported revisions to the AVMA (American Veterinary Medical Association) Guidelines...

LaFollette, M. R., Cloutier, S., Brady, C. M. et al. 2023. Benchmarking enrichment efforts in the US & Canada across species and enrichment categories. JAALAS 62(4), 303–316.

Enrichment is important for animal welfare and data quality. Provision of enrichment opportunities varies between species and enrichment category. However, data benchmarking these differences does not exist. Our objective was to characterize enrichment provision and...

McNamara, A., Ballantine, A. R., Deuchande, R. et al. 2023. Comparison of fixed and rising displacement rates of CO2 for euthanasia of aged rats. JAALAS 62(5), 453–463.

This study compared euthanasia induced by rising concentrations of CO2 in aged rats (n = 59) using different gas displacement rates. Rats were preimplanted with cardiovascular telemetry devices and had been previously used for short...

Butcher, G., Davidson, A., Sloanc, A. et al. 2021. An apparatus for automatically training and collecting individualized behavioral data with socially housed rodents. Journal of Neuroscience Methods 365, 109387.

Background: Conventional methods for individually housing, training, and testing rodents in behavioral assays can impose constraints that may limit some kinds of experimental external validity, preempt environmental enrichment, impose heavy experimenter time burdens that limit...

Paul, E. S., Browne, W., Mendl, M. T. et al. 2022. Assessing animal welfare: A triangulation of preference, judgement bias and other candidate welfare indicators. Animal Behaviour 186, 151-177.

To assess the welfare of captive animals, validated measures, so-called ‘welfare indicators’, are required. We used a triangulation approach to investigate the extent to which different measures converged to provide corroborating evidence of welfare. Laying...

Rana, M. S., Lee, C., Lea, J. M. et al. 2022. Commercial free-range laying hens’ preferences for shelters with different sunlight filtering percentages. Animals 12(3), 344.

Extreme sunlight might be aversive to free-range laying hens, discouraging them from going outside. Range enrichment with artificial shelters may protect hens from sunlight and increase range use. The preferences of 34–40-week-old Hy-Line Brown laying...

Taylor, P. S., Hemsworth, P. H., Rault, J.-L. 2022. Environmental complexity: Additional human visual contact reduced meat chickens’ fear of humans and physical items altered pecking behavior. Animals 12(3), 310.

Increased environmental complexity can improve animal welfare, depending on the resources provided and use by the animal. We provided chickens either with physical items that posed no biosecurity risk and were inexpensive (balls, chains, perches...

Campbell, D. L. M., Belson, S., Dyall, T. R. et al. 2022. Impacts of rearing enrichments on pullets’ and free-range hens’ positive behaviors across the flock cycle. Animals 12(3), 280.

Enrichment during the indoor rearing of pullets destined for free-range systems may optimize pullet development including increasing motivated natural behaviors (termed ‘positive behaviors’) including foraging, dust bathing and chick play. Hy-Line Brown® chicks (n =...

Acharya, R. Y., Hemsworth, P. H., Coleman, G. J. et al. 2022. The animal-human interface in farm animal production: Animal fear, stress, reproduction and welfare. Animals 12(4), 487.

A negative human-animal relationship (HAR) from the perspective of the animal is a limiting factor affecting farm animal welfare, as well as farm animal productivity. Research in farm animals has elucidated sequential relationships between stockperson...

Ratuski, A. S., Weary, D. M. 2022. Environmental enrichment for rats and mice housed in laboratories: A metareview. Animals 12(4), 414.

Environmental enrichment has been widely studied in rodents, but there is no consensus on what enrichment should look like or what it should achieve. Inconsistent use of the term “enrichment” creates challenges in drawing conclusions...

Rowe, E., Mullan, S. 2022. Advancing a “good life” for farm animals: Development of resource tier frameworks for on-farm assessment of positive welfare for beef cattle, broiler chicken and pigs. Animals 12(5), 565.

There is increasing recognition that farm animal welfare standards should ensure positive welfare, as well as prevent negative welfare. Resources that are valued by an animal and that provide opportunities to engage in motivated behaviours...

Mocz, F., Michel, V., Janvrot, M. et al. 2022. Positive effects of elevated platforms and straw bales on the welfare of fast-growing broiler chickens reared at two different stocking densities. Animals 12(5), 542.

In conventional rearing systems, fast-growing broiler chickens commonly experience welfare issues, such as contact dermatitis, walking difficulties or a lack of expression of species-specific behaviours. Enriching their environment may be a way to improve their...

Baker, P. E., Nicol, C. J., Weeks, C. A. 2022. The effect of hard pecking enrichment during rear on feather cover, feather pecking behaviour and beak length in beak-trimmed and intact-beak laying hen pullets. Animals 12(6), 674.

Injurious pecking, commonly controlled by beak trimming (BT), is a widespread issue in laying hens associated with thwarted foraging. This controlled study compared the effect in intact and beak-trimmed pullets of providing pecking pans to...

Sandilands, V., Baker, L., Donbavand, J. et al. 2022. Do hens use enrichments provided in free-range systems? Animals 12(8), 995.

Hens in free-range systems are given enrichments to increase foraging and limit injurious pecking, but the efficacy of enrichment types requires investigation. We studied hen behaviour and feather cover in eight commercial free-range flocks each...

Stryjek, R., Modlinska, K. 2022. Pre-exposure via wire-mesh partition reduces intraspecific aggression in male, wild-type Norway rats. Animal Welfare 31(2), 175-186.

There are instances when animals are introduced and expected to live alongside unfamiliar conspecifics within zoos, laboratories and wildlife sanctuaries. These pairings of unfamiliar animals may result in stress, trauma, or even death, in addition...

Neville, V., Mounty, J., Benato, L., Hunter, K. et al. 2022. Thinking outside the lab: Can studies of pet rats inform pet and laboratory rat welfare? Applied Animal Behaviour Science 246, 105507.

Surveys provide a low-cost means to obtain large amounts of data that are ideal for conducting exploratory research, and they are becoming an increasingly valuable tool in a veterinary context. We investigated whether surveys of...

Vasdal, G., Gebhardt-Henrich, S.G., Kittelsen, K.E. et al. 2022. Commercial broiler breeder pullet hens use perches but show no preference for perch type or height. Applied Animal Behaviour Science 249, 105608.

An important behavioral need for laying hens is perching, but few studies have investigated perching behavior in commercial broiler breeder pullets. The aim of this study was to investigate perching behavior throughout the pullet period...

Mels, C., Niebuhr, K., Futschik, A. et al. 2022. Predictors for plumage damage and bloody lesions indicative of feather pecking in pullets reared in aviaries. Applied Animal Behaviour Science 250, 105607.

Feather pecking remains a serious problem in poultry farming. This study aimed to identify risk factors for plumage damage as a proxy for feather pecking, and the predictive value of practical animal-based parameters. Data were...

Onbaşılar, E. E. 2022. Effect of alternative litter materials on the behaviour of male broilers. Behavioural Processes 195, 104566.

The welfare of broilers is strongly dependent on the litter material because they spend their life in contact with it. The purpose of this study was to determine the effects of alternative litter materials on...

Denommé, M. R., Mason, G. J. 2022. Social buffering as a tool for improving rodent welfare. JAALAS 61(1), 5-14.

The presence of a conspecific can be calming to some species of animal during stress, a phenomenon known as social buffering. For rodents, social buffering can reduce the perception of and reaction to aversive experiences...

Nicolis, I. N., Beale, C. N., Bidot, W. A. et al. 2022. Performance and consistency of circulating warm water blankets for rodents. JAALAS 61(1), 96-100.

General anesthesia as used for rodent research can have adverse effects on physiologic mechanisms. Thermoregulation is often greatly inhibited, with resultant deleterious effects on cardiac and respiratory function. These potential effects can be mitigated by...

Hickman, D. L. 2022. Evaluation of carbon dioxide euthanasia of female Sprague Dawley rats alone or with unfamiliar conspecifics. JAALAS 61(2), 195-200.

Most studies evaluating methods of euthanasia to date have focused on the euthanasia of individual animals. However, larger chambers are commonly used to euthanize multiple cages of animals at once. This study evaluated the use...

Bigelow, L. J., Cohen, A. J., Pimm, R. et al. 2022. Ultrasonic vocalization analysis as a novel metric to assess cage enrichment in rats. JAALAS 61(2), 140-148.

Laboratory rodent housing conditions vary significantly across laboratories and facilities. Variation in housing can be associated with animal stress leading to study variability and the subsequent inability to replicate experimental findings. Optimization and standardization of...

Medina, A. 2022. Creative enrichment for nonhuman primates. Laboratory Animal Science Professional 10(1) (January/February), 42-43.

Providing novel and creative enrichments for nonhuman primates improves their mental wellbeing and is thus an important aspect of all husbandry programs. These enrichments are often presented through variations in diet, toys, and environmental features...