Liv Brancato-Buentello, NA3RsC Intern

Animals have been instrumental in scientific research to aid in medical advancements. Low stress handling has been gaining awareness as an alternative to traditional animal handling to ensure the animals have more positive outcomes in laboratories as well as in veterinary hospital settings. Low stress handling is a set of techniques used to maximize an animal’s comfort level so that the handler can perform necessary treatments safely and effectively while maintaining animal welfare. These techniques range from using tunnel handling for mice to giving cats a soundproof room to alleviate their fear. These small modifications can greatly decrease animal anxiety and therefore create a safer environment for the animal as well as the handler.

Although some handling is inevitable, there is research to show the safety and comfort of handlers and animals is achievable by using simple techniques so that mice can have a positive association with human contact. Traditionally, mice were picked up by the base of their tail, which is a technique that was quite easy for the handler, yet the mice responded poorly to this method. To a mouse, being picked up by the tail from the home cage is like being picked up by a predator and they never habituate to this method. The scientists, Hurst and West concluded that tail handling used to handle laboratory mice elevated their stress levels creating potential study confounders.

Picking mice up from their home cage using a tunnel or an open hand approach allows for voluntary interactions between mice and humans, reducing their stress levels. Multiple studies done with both sexes and across multiple strains have shown that using a tunnel or open hands in comparison to tail handling results in mice that display reduced stress hormones, reduced anxiety, increased glucose tolerance, improved reliability in behavioral tests, improved breeding parameters, and will voluntarily interact with the handler.

The impact of less stressed animals could be significant in the quality of the data generated during research trials.

There are many frequently asked questions when switching to a new handling technique such as time, biosecurity, how to perform procedures, logistics, etc. These are all valid questions but are not obstacles to implementing low stress handling and are addressed in multiple resources such as the North American 3Rs Collaborative website and the NC3Rs website. These also have excellent videos, downloadable slide decks, webinars, and many more resources on mouse low stress handling.

The North American 3Rs Collaborative has been working on a 3Rs course to better educate the research community on the positive changes that low stress handling can have on the laboratory environment.

What are the 3Rs?

• Refinement refers to methods that minimize the pain, suffering, and distress of research animals as well as improves their welfare.
• Reduction refers to methods that minimize the number of animals required per experiment, or study design, to still achieve robust results.
• Replacement refers to methods or technologies which avoid, or replace, the use of animals entirely.

Low stress handling is better for the welfare of the animals and for the overall research.

Citations

• Hurst, J. L., & West, R. S. (2010). Taming anxiety in laboratory mice. Nature methods, 7(10), 825-826.
• Gouveia, K., & Hurst, J. L. (2019). Improving the practicality of using non-aversive handling methods to reduce background stress and anxiety in laboratory mice. Scientific reports, 9(1), 1-19.
• Hull, M. A., Reynolds, P. S., & Nunamaker, E. A. (2022). Effects of non-aversive versus tail-lift handling on breeding productivity in a C57BL/6J mouse colony. PloS one, 17(1), e0263192.