Examples of 3Rs methods

Plastic rat models are useful in Laboratory Animal Science courses

Examples of the incorporation of 3Rs methods in practice:


  • Replacement: eventually, this is the desired aim for scientific methods in which the animal experiments are effectively replaced by animal-free methods. For example computer models or in vitro methods involving cells- and tissue cultures. For educational purposes, plastic rat models are useful in rat anatomy, or bicycle inner tubes are used by students to practice suturing.
  • Reduction: the number of animals for every experimental procedure has to be reduced as much as possible. The researcher has to set up an experiment in a proper and robust manner; by properly utilizing statistical methods to obtain significant results with as few animals as possible, by choosing the right experimental model and by smart breeding techniques to ensure that as few 'surplus' animals as possible are bred. Experimenters can also use modern laboratory instruments like MRI-scans, to follow tumor growth stadia of one animal instead of using more animals. Body parts and organs of one animal could also be used in separate experiments.
  • Refinement: another very important method for responsibly dealing with experiments on animals is to alleviate the pain or stress that they can experience, before, during and after the experiments, to minimize the possible harm to their welfare. Optimal housing conditions, behavioural monitoring and applying anesthetics or analgesics when necessary are important to take into account, as well as humane endpoints. Humane endpoints are the earliest indicator in an animal experiment of (potential) pain and/or distress that can be used to avoid or limit pain and/or distress by taking proper actions, such as humane killing or terminating the experimental procedure. The ultimate goal is to minimize the pain and distress or any other form of harm to the welfare of the animal.