What are the 3Rs?
Humane animal research should follow the principles of Replacement, Reduction, & Refinement (the 3Rs).
These principles were laid out 60 years ago in the book The Principles of Humane Experimental Techniques by William Russell and Rex Birch. The 3Rs are internationally accepted principles for the ethical consideration of animals in research. They are often key goals for organizations and regulatory bodies that conduct animal research. Furthermore, public attitudes towards animal research are more positive when the 3Rs are used. Are you a member of the public curious about the 3Rs? Check out this webpage.
3RsC has created a 3Rs certificate program for anyone working with animals in the field to learn more about the 3Rs. Click here to learn more.
We believe that for humane animal research, all 3Rs must be applied thoroughly, beginning with a determination if Replacement is achievable, and only if not, then moving on to Reduction and Refinement. Ultimately, the goal is to increase the benefits of research and improve animal welfare.
We believe that for humane animal research, all 3Rs must be applied thoroughly, beginning with a determination if Replacement is achievable, and only if not, then moving on to Reduction and Refinement. Ultimately, the goal is to increase the benefits of research and improve animal welfare.
Replacement
Replacement refers to methods or technologies which avoid the use of live animals in favor of other predictive, robust methods. Examples of replacement include include in vitro (e.g., cell culture, microphysiological systems), in silico (e.g., computational modeling, artificial intelligence), in chemico (e.g., environmental health monitoring), and ex vivo methods (e.g., manipulation of human tissues outside the body). Replacement occurs along a continuum as although some current replacements do not use animals in primary experiments, but still require animal-derived components, which means animals are required to be used for their implementation. A method is considered a replacement if it eliminates animal use at the point of primary experimentation, even if animals are involved elsewhere in the broader experimental pipeline
Partial or relative replacement refers to methods that may require insentient animals or animal tissues, but the animals are not exposed to any pain or distress in the experiment at hand. This may include tissue sharing from agricultural or other projects, data sharing, or using animals such as fruit flies, nematodes, amoebae, and immature forms of vertebrates.
Reduction
Reduction refers to methods that minimize the number of animals required to conduct robust research with valid experimental and statistical designs to answer justifiable scientific questions. Examples of reduction include implementing powerful, high-quality experimental design and analysis practices that are robust and reproducible, resulting in a "right sized" project that uses the minimum number of animals to fulfill the requirement and objective of the test. Studies should be fully reported (including null results) to further ensure maximum benefits are achieved from each animal study. Reduction only occurs once an animal study has been deemed necessary. Additional examples of reduction include responsible animal breeding and, in well justified cases, re-use of animals.
Refinement
Refinement refers to any approaches that holistically improve animal welfare across the entire animal lifespan including procedures, housing, handling, and habituation. This includes meeting animal's basic needs, promoting positive welfare, and minimizing pain, suffering, and distress. Examples of refinements include modifying experimental procedures to reduce distress, improving housing and handling to allow greater choice and control, and providing for opportunities for animals to express species-specific behaviors. Other tools may include severity assessments, implementation of humane endpoints and interventions, monitoring cumulative burden, ensuring that animal care staff have the authority to act, and retrospective review.