Reduction: A Measure You Can’t Measure

The 3Rs – Replacement, Refinement and Reduction of animal research – can we measure the impact? Seems easy enough, but there are challenges.

How many experiments have been replaced by non-animal alternatives? Do we count every time a cell culture is used in an experiment that might once have been done in vivo? No. While some critics point to the relatively small sums of money that organisations like the Dr Hadwen Trust or NC3Rs spend on research in replacement, few note the huge sums spent by industry on researching and using alternatives.

Refinement is even harder to quantify. Do we look at the money spent on refinement? Do we include bigger, better enclosures? What about the smaller enclosure before that were still better than the ones that preceded it? How do you put a measure of social housing of animals? Once again measurement becomes nigh on impossible.

So, we arrive at the third R – Reduction. Surely this is the easiest to measure, we simply look at the total number of animals used in research and see how the numbers have changed?

The US has seen a 50% decline in the use of AWA-covered animals since 1992, despite a slight rise in 2010. However, it is unknown whether this fall has correlated with a similar fall in the use of mice, or whether researchers have been choosing to use mice instead of “higher” animals.

In the UK, where all vertebrates are counted, there has been a steady rise since 2001, from 2.6 million procedures (slightly fewer animals) to 3.8 million (2011).

Number of Animals used in research UK Home Office

Does this mean the UK is failing to implement the principle of Reduction? The British Union for the Abolition for Vivisection certainly think so. In their new “Broken Promises” campaign they say:

The Government is failing on its pledge to work to reduce the use of animals in research. This is an issue where there is strong public concern yet the latest statistics show that animal experiments in the UK are at an all-time high since 1986 (the introduction of the Animals (Scientific Procedures) Act in Great Britain).

When the Coalition Government took office in 2010 it’s Programme for Government included the pledge to “work to reduce the use of animals in scientific research.” This was included after strong lobbying from the BUAV, and we have been leading the way in holding the Government to account ever since.

However, the latest statistics from the Home Office show that despite this pledge the number of animals being used in experiments is now more than 3.7 million, the highest figure for 25 years.

It is true that the number of animals used in research has risen since 2001. One of the main reasons for this is the huge rise in funding for animal research. Since 1995 (remember that funding has a lagged effect on the number of animals used), the expenditure on bioscience and medicine R&D in the UK has gone up by 150%, while the number of animals has risen by only 30% – that means that animal use is shrinking as a percentage of funds (though this effect will be slightly mitigated by the fact that animal use has become more expensive over the period).

Rises in funding in Biomedical research in the UK

We must realise that Reduction is not about using less total animals, but like the other Rs, is about the conduct of individual experiments. Russell and Burch, who first described the 3Rs in 1959, described Reduction as:

Reduction means reduction in the numbers of animals used to obtain information of a given amount and precision.

It is about using fewer animals to obtain given pieces of information, i.e. individual experiments (not the total in a country). Scientists have been effective at reducing the number of animals they use in experiments thanks to better models and improved scanning devices. Whereas at one time a cancer study might have involved 10 rats being euthanised one a fortnight to study the progress of a tumour, modern scanning techniques can allow the tumour of one rat to be studied non-invasively over the whole period – reducing the number of animals used. Counting these reductions is difficult. The NC3Rs provide a similar example:

There are many examples, including in the research we fund on cancer drug screening, where new methods allow animal studies to be avoided. These are not one to one replacements for the animal studies. Instead new in vitro tools are used to screen drugs so that only those that are likely to be suitable for further development are taken into animal studies. This avoids wasting animals on drugs destined to fail in preclinical development – animals which would,

if used, have been recorded in the statistics. It is difficult to envisage how collecting information centrally on efforts to avoid unnecessary animal use could be done in practice (without an unnecessary burden on scientists and institutions) but it does illustrate the complexity of measuring the 3Rs.

The National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs), which works to implement and fund the 3Rs, warned against drawing conclusions from the “total” number of animals released by the Home Office, saying:

The annual statistics published by the Home Office on procedures performed under the Animals (Scientific Procedures) Act 1986 contain a large amount of information on animal use – numbers, species and purpose. At first sight it would be expected that they would be a good benchmark on 3Rs activities in the UK and indeed they are routinely used in this way by some campaign organisations. The statistics were, however, never intended to be a gauge of progress in the 3Rs, and in any case their utility for such a purpose is limited for a number of reasons.

They went on to provide possible reasons for a rise in the number of animals used (now or in the future):

  • Strategic investments in particular research areas or geographic locations:
    This includes when Pharmaceutical companies relocate between countries, changing the numbers of animals used in old and new locations.
  • Availability of new technologies:
    The introduction of GM animals resulted in most of the UK’s increase over the past decade
  • Regulatory Requirements:
    The EU’s REACH legislation could potentially increase the number of animals tests in Europe by 9 to 64 million additional animals.

The BUAV are disingenuous when they describe the Government as failing to meet their pledge on reduction. There has been in the past, and continues to be, great strides in managing the reduction of animal research in individual experiments. It would be wrong for the Government to call on a general reduction in the total number of animals as they cannot predict the course of medical development in the coming years.

Speaking of Research


It is also worth remembering that an arbitrary reduction in the number of animal experiments in the UK (or another country) would simply push that research to countries with lower animal welfare standards. In the words of Mark Harper MP, the UK Government minister on this issue:

Of course, the quickest way to reduce the number of animals would be to drive the work overseas, which would not be good for the United Kingdom, for jobs or for animal welfare. We must be thoughtful about the numbers. We should consider the size of the industry and the work that is being carried out, and whether we are driving down the proportion of animals being used in that work.