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Refinement References & Resources (Environmental Enrichment)

Baumans, V. (2005). Environmental enrichment for laboratory rodents and rabbits: requirements of rodents, rabbits, and research. ILAR Journal / National Research Council, Institute of Laboratory Animal Resources 46, 162-170.

  • Rodents, rabbits: Species-specific behaviors/needs  
  • Environmental enrichment should be regarded as an essential component of an overall animal care program, equally as important as nutrition and veterinary care. It is also important to evaluate the impact of enrichment on scientific outcome.

Benaroya-Milshtein, N., Hollander, N., Apter, A., Kukulansky, N., et al. (2004).     Environmental enrichment in mice decreases anxiety, attenuates stress responses and enhances natural killer cell activity. European Journal of Neurosciences 20, 1341-1347.

  • Mice, environmental enrichment (EE); EE mice showed decreased anxiety-like behavior and higher activity
  • “The most important new discovery of this study is the enhancement of NK cell activity by EE”

Croney, C.C. and Newberry, R. C. (2007). Group size and cognitive processes. Applied Animal Behaviour Science 103, 215-228.

  • Various animal species; group size, cognition, social complexity, social learning
  • Understanding the relationship between group size and cognition in animals may yield practical animal management benefits and improved animal welfare

Engel, A.K.J., Gross, A.N., Richter, J.R., et al (2011). Variation in stress reactivity affects cage-induced stereotypies in female CD-1 (ICR) mice. Applied Animal Behaviour Science 133, 101-108.

  • Mice, stress reactivity, cage-induced stereotypies, HPA response, corticosterone
  • A trend for reduced recovery of the corticosterone response suggests that variation in recovery rather than the acute response might predict recovery levels in these mice

Flecknell, P.A. (2010). Do mice have a pain face? Nature Methods 6, 437-439.

  • Mice, pain assessment, facial expression, mouse grimace scale
  • Langford et al data indicate that that changes in facial expression, coded using a method analogous to action coding systems in humans, can be used to evaluate pain in mice

Fraser, D. (2009). Assessing animal welfare: Different philosophies, different scientific approaches. Zoo Biology 28, 507-518.

  • Animal welfare, animal welfare assessment, “affective states,” “normal pleasures,” behavior natural for the species
  • Efforts to improve animal welfare need to strike a balance among the different animal welfare objectives: to ensure good physical health and functioning of animals; to minimize unpleasant “affective states” (pain, fear, etc) and allow normal pleasures; to allow animals to live in ways natural for the species.

Held, S.D.E. and Spinka, M. (2011). Animal play and animal welfare. Animal Behaviour 81, 891-899.

  • Animal play, animal welfare, the play-welfare relationship
  • Play should be investigated not only as a potential welfare indicator but also as an agent for improving the current and future welfare of an individual or group

Jochems, C.E.A., van der Valk, J.B.F., Stafleu, F.R., and Baumans, V. (2002). The use of fetal bovine serum: ethical or scientific problem? Alternatives to Laboratory Animals: ATLA 30, 219-227.

  • Fetal bovine serum (FBS), fetal pain, animal cell culture media, cardiac puncture, pain and distress, moral concerns
  • Current practice of fetal blood harvest is inhumane; efforts should be made to reduce and preferably replace FBS by synthetic alternatives 

Karp, C. L. (2012). Unstressing intemperate models: how cold stress undermines mouse modeling. J. Exp Med Vol 209 No 6, 1069-1074.

  • Mice, cold stress, mouse modeling
  • Available data suggest that the cold stress to which lab mice are subjected profoundly affects mouse physiology in ways that impair the modeling of human homeostasis and disease.  

Kirkden, R.D. and Pajor, E.A. (2006). Using preference, motivation and aversion tests to ask scientific questions about animal feelings. Applied Animal Behaviour Science 100, 29-47.

  • Preference, motivation and aversion tests, operant tests, animal feelings, animal welfare
  • Preference and motivation tests are still under development, but if properly interpreted and integrated with other measures they constitute a powerful tool for the assessment of welfare.

Ladewig, J. (2005). Of mice and men: Improved welfare through clinical ethology. Applied Animal Behaviour Science 92, 183-192.

  • Welfare, clinical ethology, behavior problems
  • As many behavior problems are related to the way people house and handle domestic animals, possibly the most important aspect of clinical ethology is its focus on the human-animal interaction.

Langford, D.J., Bailey, A.L., Chanda, M.L., Clarke, S.E., et al. (2010). Brief Communications: Coding of facial expressions of pain in the laboratory mouse. Nature Methods 7, 447-449

  • Mice, facial expressions, mouse grimace scale, subjective pain experience
  • A standardized facial coding system (characterized by high accuracy, reliability, and validity can be used to assess pain in the lab mouse for veterinary care and drug development.     

Macri, S. and Würbel, H. (2006). Developmental plasticity of HPA and fear responses in rats: A critical review of the maternal mediation hypothesis. Hormones and Behavior 50, 667-680.

  • "Rats, developmental plasticity, HPA, fear responses, maternal mediation hypothesis class
  • Developmental plasticity of HPA and fear responses in rats and other animals has important implications for the design of animal experiments and for the well-being of experimental animals.

Mason, G., Clubb, R., Latham, N., and Vickery, S. (2006). Why and how should we use environmental enrichment to tackle stereotypic behaviour? Applied Animal Behaviour Science 102, 163-188.

  • Environmental enrichment, stereotypic behavior, abnormal repetitive behaviors (ARBs), motivational frustration, animal welfare, zoo/captive animals.
  • Enrichment is the preferred approach to tackle the problems underlying stereotypic behaviors.

Martin, B., Ji, S., Maudsley, S., and Mattson, M.P. (Apr 6, 2010). “Control” laboratory rodents are metabolically morbid: Why it matters. PNAS 107, 6127-6133.

  • Laboratory rodents, mice, environmental enrichment, animal welfare, standardization, replicability, refinement, reduction, external validity, systematic randomization
  • We show that animal welfare can be improved by beneficial enrichments without disrupting standardization and that standardization is a flawed concept

Mench, J.A. and Swanson, J.C. (2000). “Developing Science-Based Animal Welfare Guidelines,” a speech delivered at the 2000 Poultry Symposium and Egg Processing Workshop.

  • Caged laying hens, animal welfare, animal welfare guidelines, husbandry, hen space guidelines (example)
  • Because science and values are both dynamic, guidelines must be dynamic too. Animal welfare guidelines constructed to address both science and public values will be more likely to stand the test of time. 

Pham, T.M., Brené, S., and Baumans, V. (2005). Behavioral assessment of intermittent wheel running in mice in the laboratory. Journal of applied animal welfare science: JAAWS 8, 157-173.

  • Mice, enrichment, running wheels, individual housing, enriched physical and social conditions, open-field test
  • Wheel running normalizes some effects of intermittent separation from the enriched, social home cage  

Sherwin, C.M., Christiansen, S.B., Duncan, I.J.H., Erhard, H.W., et al. (2003). Guidelines for the ethical use of animals in applied ethology studies.  Applied Animal Behaviour Science 81, 291-305.

  • Applied ethology, animal welfare, “costs” to the animal, guidelines vs. regulations, ethical principles, decision models
  • Aims to provide researchers engaged in applied ethology with a basis for self-evaluation of the ethical nature of their work

Sherwin, C.M., Haug, E., Terkelsen, N., and Vadgama, M. (2004). Studies on the motivation for burrowing by laboratory mice.  Applied Animal Behaviour Science 88, 343-358.

  • Mice, burrowing, behavioral need, strength of motivation, operant technique
  • The data show that burrowing is a “natural” or “normal behavior of lab mice, it appears to constitute “a behavioral need, and it is highly motivated.

Sztainberg, Y. and Chen, A. (2010). An environmental enrichment model for mice. Nature Protocols 5, 1535-1539.

  • Mice, environmental enrichment, anxiolytic-like effect, species-specific behavioral repertoire, enhanced sensory, cognitive, motor, and social stimulation
  • One of the most robust effects of environmental enrichment is the reduction of anxiety levels

Van de Weerd, H.A., Pascalle, L.P., and Van Loo, P.L.P. (2004). Environmental enrichment: Room for reduction? Alternatives to Laboratory Animals: ATLA 32 suppl 2, 69-71.

  • Mice, environmental enrichment, reduction, refinement, nesting materials, husbandry, aggressive behavior, variation
  • Gives examples of enrichment leading to reduction: beneficial effects of nesting materials for lab mice; the effects of husbandry procedures on controlling aggressive behavior in male lab mice; and the effects of environmental enrichment on variation in the results

Van de Weerd, H.A., Aarsen, E.L., Mulder, A., Kruitwagen, et al. (2002). Effects of environmental enrichment for mice: variation in experimental results. Journal of applied animal welfare science: JAAWS 5, 87-109.

  • Mice, environmental enrichment, potency testing for tetanus vaccine, stress-induced hypothermia, variability of results
  • When enrichment does not influence variability, there is no reason for not introducing cage enrichment and by doing so contributing to the animals’ welfare.

Van Loo, P.L.P., Blom, H.I.M., Meijer, M.K., and Baumans, V. (2005). Assessment of the use of two commercially available environmental enrichments by laboratory mice by preference testing. Laboratory Animals 39, 58-67.

Würbel, H. (2007). Environmental enrichment does not disrupt standardization of animal experiments. ALTEX 24, Special Issue, 70-73.

  • Lab mice, environmental enrichment, abnormal behaviors, well-being, standardization
  • Well-being and normal brain development of mice housed in barren cages may be seriously impaired and may question the validity of studies done with these animals

Würbel, H. and Garner, J.P. (2007). Refinement of rodent research through environmental enrichment and systematic randomization.

  • Rodents, environmental enrichment, systematic randomization
  • Animal welfare can be improved by beneficial enrichments; the concept of standardization is flawed and needs to be profoundly revised

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