3Rs Principles Print

For many years it has been thought that one day it would be possible to completely replace the testing of compounds by the use of modeling and test tube methods. Unfortunately, due to the complexity of the human body, this will not be possible in the foreseeable future.

The principles of the 3Rs - Replacement, Refinement and Reduction - were originally developed by Professor William Russell and Rex Burch, and are now widely accepted internationally as criteria for humane animal use in research and testing.

Replacement refers to methods, which avoid or replace the use of animals in areas where animals would otherwise have been used.

This includes both absolute and relative replacements such as:

  • Computer modelling, in vitro methodologies, human volunteers
  • Established animal cell lines and animal cells, tissues and organs where the animal is killed by a humane technique before collection of the material

Refinement refers to improvements to housing and care and procedures, which minimise actual or potential pain, suffering, distress or lasting harm and/or improve animal welfare in situations where the use of animals is unavoidable.

Refinement refers to the lifetime experience of the animal. There is evidence that refinement not only benefits animals, but also improves the quality of research findings.

Examples include:.

  • Providing appropriate anaesthetic and analgesic regimes;
  • Training animals to "co-operate" with certain procedures (e.g. taking blood samples) so the animals are less stressed;
  • Ensuring that accommodation meets the animals' needs (e.g. providing opportunities for nesting for rodents);
  • Replacement of higher species with lower species (e.g. from non human primates to mice, from mammals to cold blooded animals).

Reduction refers to methods which minimise animal use and enable researchers to obtain comparable levels of information from fewer animals or to obtain more information from the same number of animals, thereby reducing future use of animals.

Examples include:

  • Improved experimental design and statistical analysis;
  • Techniques, such as imaging, which require smaller numbers of animals.