Reduction and refinement applied to animal models

Volumes II and III of this handbook have described the use of animals as models for humans in different biomedical research areas. Specialist animal care staff-laboratory animal caregivers, technicians, and specialist veterinarians-are normally responsible for the health and well-being of the animals when the animals are not on experiment. The designs of experiments, however, as the procedures and manipulations themselves, are generally the responsibility of a licensed scientist. Consequently, we have devoted this final, brief chapter of the handbook to a discussion of issues of general relevance with respect to using the right number of animals to generate reliable results, which are not just of sufficient power and statistical significance, but are also meaningful for extrapolation-or to use a more modern expression, have “translational validity”—to humans. The obvious goal is to minimize the number of animals used, without compromising the validity of the results in terms of their relevance for human biology. We also discuss ways to continuously refine the use of animals through gentling, habituating, desensitizing, conditioning, and training of the animals, and through the use of minimally invasive procedures. The aim is to ultimately remove fear from experimental treatments and to ensure that all unnecessary pain, harm, distress, and suffering are either eliminated by handling refinements or effectively alleviated by proper medication.