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Welfare of Animals Used in Scientific Testing and Research

'Improvements in the care of animals are not now likely to come of their own accord, merely by wishing them: there must be research... and it is in sponsoring research of this kind, and making its results widely known, that UFAW performs one of its most valuable services.'

Sir Peter Medawar, 1960 Nobel laureate in Physiology or Medicine

Tens of millions of animals are used around the world every year in scientific research and testing.  Despite recent advances that have led to fewer animals being used for some purposes, the total number of animals used in research has grown over recent years, most probably because more biomedical research is being carried out around the world. The most commonly used animals are mice, fish and rats, but many other species including monkeys, cats, dogs, horses and pigs are also used.

Why are animals used?

Animals are used for many reasons including; basic research to understand biological processes; development of new medicines and treatments; testing the safety of substances which might be dangerous to humans or the environment and for teaching.

Animals are mostly used to develop and test treatments for human conditions and to understand human biology, but also to develop veterinary treatments for other animals and to obtain fundamental knowledge.

How does research affect animal welfare?

The impact of research on animals varies from almost insignificant effects on some animals (for instance where nothing more occurs than observation of their behaviour), to major effects on some that undergo very painful or distressing procedures. The welfare of animals may also be affected if their housing and husbandry does not meet their needs.

In some cases harm may be caused as an unintended consequence of the research (for instance, the pain of an injection or surgery where the objective was to place a sensor to monitor some biological function). Less commonly, research on animals causes deliberate harm when the objective is to induce serious diseases or injuries so that treatments can be tested, for example.

What kind of harm do animals used in research experience?


Some experiments may involve surgery on animals or the induction of potentially painful conditions like arthritis or cancer to look for new treatments. Whilst there is some debate about how animals perceive and process pain it is likely that many animal species do suffer painful experiences. Research has shown that many species respond to stimuli that would be painful in humans and that painkilling drugs can reduce their responses to such stimuli. The more we learn about different species, the more we suspect that many are capable of feeling pain. It now seems possible that even fish and crustaceans experience pain, for instance. As our understanding of animal pain has developed, great progress has also been made in diagnosing and treating it, and it is now far more common to treat pain in animals used in research than it was many years ago.

Other states of poor welfare

Many animals also seem to be capable of experiencing poor welfare caused by something other than pain. In fact, animals are sometimes used to model human mood disorders by deliberately exposing them to experiences that make them anxious or depressed. The way animals are housed can cause welfare problems too. As an example; mice are often kept in groups in cages. Many factors in these cages can compromise their welfare such as the temperature, the amount of space available and the social group with which they are housed (they will sometimes fight, for instance). Primates used in research are sometimes housed singly, in relatively small cages, which can cause emotional problems for these highly social animals. An important area of research on the welfare of research animals is the search for better ways to house and handle them.

How has UFAW helped?

UFAW has worked since its foundation in 1926 to improve the welfare of animals used in research by supporting scientific studies to understand and improve their welfare alongside education and training to improve the lives of animals used for scientific purposes worldwide.

The 3Rs

Whilst working for UFAW in the 1950s William Russell and Rex Burch developed the concept of the 3Rs – Replacement, Reduction and Refinement (set out in their seminal book – The Principles of Humane Experimental Technique) and these principles are now broadly accepted as the framework under which research on animals should be conducted. The 3Rs principles suggest that there are three ways to lessen the impact of scientific research on animals:

  1. Replace animals with other ways of gaining the knowledge required (by using computer models, tissue culture, artificial organs etc. to understand biological processes)
  2. Reduce the number of animals used to achieve the results (for example by doing more efficient experiments which use fewer animals)
  3. Refine the way animals are treated to minimise any impacts upon them (the aim being to cause less suffering to the animals or to improve their welfare whilst still achieving the scientific aims)

You can read here about the history of the 3Rs and of  how UFAW developed the non-confrontational approach that was led to the 3Rs, of some of the outcomes and the impact of the 3Rs today when they have been incorporated into legislation and codes of practice to improve the welfare of animals used in research throughout the world.

UFAW has supported developments in all of the 3Rs which have resulted in improvements to the welfare of millions of animals. Here are just a few examples:


UFAW funded work at Oxford University to find new ways of testing candidate TB vaccines. At the moment vaccines against TB (which still kills more than a million people every year) are tested extensively on mice. Rachel Tanner and her colleagues are working to develop an assay to determine vaccine efficacy in vitro which could drastically reduce the number of animals used in the initial vaccine testing stages.

Tanner R, McShane H. (2-16) Replacing, reducing and refining the use of animals in tuberculosis vaccine research. ALTEX. doi: 10.14573/altex.1607281. [Epub ahead of print]





UFAW-funded research in the laboratory of Professor Georgia Mason at the University
of Guelph in Canada showed that different strains of mice could be housed in the same cages without impacting their welfare (previous concerns were that the strains might figh
t). This means that very efficient experiments using different strains of mice to improve the reliability of results can be used so that, in total, fewer mice are used in each experiment.

Walker M, Fureix C, Palme R, Newman JA, Ahloy Dallaire J, Mason G. (2016)

Mixed-strain housing for female C57BL/6, DBA/2, and BALB/c mice: validating a split-plot design that promotes refinement and reduction. BMC Med Res Methodol;16:11. doi: 10.1186/s12874-016-0113-7.


For the foreseeable future many animals will continue to be used in research. Whilst animals are used it is important to look for ways to improve their lives and reduce the impacts of research upon them.

Recently, the UFAW William Russell Research Fellow Professor Joe Garner, Dr. Brianna Gaskill and colleagues examined the thermal comfort of mice used in research. Their research indicated that most mice are too cold – mice prefer to be rather warm – about 25oC, much warmer than most research housing. One solution would be to increase room temperatures, but the researchers showed that a much better solution is to give mice nesting material such as strips of paper. Mice build their own nests out of the paper, much as they would build nests in the wild. Once inside the nests, the mice are insulated and much warmer than they would be outside. If they get too warm they can simply leave the nest, so they have control over their own temperature. Furthermore, the very act of constructing the nest provided stimulation for the animals. The provision of nesting material for mice is already routine in some countries and is becoming more widely accepted worldwide, making life more comfortable for millions of these animals around the world. Recently, new research has even showed that by checking how well the mice are building the nests it’s possible to identify animals which are sick or in pain because they stop building such elaborate nests.

Gaskill BN, Gordon CJ, Pajor EA, Lucas JR, Davis JK, et al. (2012) Heat or Insulation: Behavioral Titration of Mouse Preference for Warmth or Access to a Nest. PLoS ONE 7(3): e32799. doi:10.1371/journal.pone.0032799

Another recent UFAW project looked at ways to monitor the welfare of mice developing experimentally-induced cancers. Dr Claire Richardson at Newcastle University worked on developing automated measurements which could be used to continuously monitor the welfare of the mice – logging their temperature, how much they drank and how much they move around and thus providing early warning when they begin to become sick, allowing them to be treated or humanely killed to relieve their suffering. This means mice with experimental cancer or other conditions suffer less than if less sophisticated tests of their welfare based just upon observation of them in their cages is used.

Education and Training

UFAW works to share knowledge about the welfare of research animals through its website, scientific meetings and publications. Since 1947 the UFAW Handbook on the Care and Management of Laboratory and Other Research Animals, now in its 8th edition, has provided up to date advice and information, to professionals caring for these animals. UFAW has also published a series of animal welfare books including a volume on the welfare of animals used in research. The scientific journal Animal Welfare also publishes the latest research on animal welfare, often including papers relevant to those who use animals in research.

UFAW regularly organises scientific meetings at which those who study animal welfare share their findings with colleagues and those who care for or use animals in research, making sure that the latest findings are translated into better treatment for animals.

When governments or regulators seek to change the rules and guidance about how animals are treated in research they frequently seek UFAW’s expert opinion and guidance.

The Future

Huge advances have been made in the treatment of animals used for scientific purposes. Far fewer animals suffer severely as a result of research.  Nonetheless, there is much more that remains to be done to advance all of the 3Rs. Research is needed to develop refinements to experimental techniques to reduce suffering and to find ways to replace and reduce the use of animals in research. Our knowledge about animals’ needs in captivity also needs to be expanded to inform legal standards worldwide.

It is likely that new challenges to animal welfare may also arise as new technologies are developed. As long as animals are used in scientific testing and research, UFAW will play a crucial role in ensuring that animal suffering in the name of science is minimised or eradicated through the development and application of animal welfare .

Your support in helping UFAW to improve the lives of animals used in research is much needed and you can find out how you can help here.