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Use of Laboratory Animals in 2023

Every year, the German Federal Institute for Risk Assessment (BfR) fulfils a legal obligation to receive and compile data from the competent authorities of the federal states of Germany on the use of laboratory animals in facilities located in the respective states. The compiled dataset on the use of laboratory animals in all of Germany is then submitted by the BfR to the European Commission.

In 2023, the number of laboratory animals used declined for the fourth year in a row. The almost 16% decline from the previous year was comparatively stark.

Alongside figures about the use of animals in experiments, annual data on the numbers of animals killed are also collected in Germany. The number of animals killed in order to use their organs and tissue for scientific purposes declined by almost 6% from the previous year. The number of laboratory animals killed but not used also declined by approximately 22%. These two sets of figures are submitted to the European Commission every five years. The next submission is set for the year 2028 for the 2027 reporting year.

In their data report “Laboratory animals used in 2023 in Germany in numbers”, which comprises 48 tables, the BfR is publishing the collected data which is broken down by various topics.

Detailed explanation of the data collected:

Total number of animals used in 2023

In 2023, almost 1.46 million vertebrates and cephalopods were used in animal experiments in Germany, in accordance with section 7(2) of the German Animal Welfare Act (TierSchG). This is a substantial decrease of around 16% from 2022 (just under 1.73 million laboratory animals used). When reporting the animals used, a distinction is made between animals used for the first time and animals that are re-used (see Table 1). First-time use means that the animals had not been used in an experimental project and are being reported for the first time. Re-use indicates that an animal had been previously used in an experimental project and has already been included in a report, after which it was re-used in another experimental project. In Table 21 of the detailed report, the numbers of first-time use and re-used animals are broken down by species.

In addition to the requirements of the EU Laboratory Animal Directive 2010/63/EU, data is also collected in Germany on animals that have been killed for scientific purposes (TierSchG section 4(3)) without prior interventions or treatments – such as when using organs or tissue from these animals for scientific purposes (see Table 1).  Compared to 2022, this number has decreased by around 6%. A detailed list of the animals killed for scientific purposes by species can be found in Table 47  the report. The number of animals used in experiments and the number of animals killed for scientific purposes totals around 2.1 million usages of laboratory animals for the year 2023. This represents an overall decline of around 12.7% compared with 2022.

Beginning in the 2021 reporting year, data is now also collected in Germany on the animals that are bred for animal experiments or for the use of their organs or tissue for scientific purposes, but which were subsequently killed without being used for such purposes (see Table 1). These animals include the offspring of genetically modified lines, for example, where the animals do not exhibit the required genetic changes and could not then be used for any other scientific purpose. This category also includes laboratory animals killed for the purpose of monitoring breeding colony hygiene, for example. The category also includes animals that could not be used in research for other reasons – because the animals were too old, for example, or did not have the right sex as required for the specific experiment.

Around 1.37 million animals which were not used and then killed were reported in the 2023 reporting year. This is a clear decrease of around 22% compared to 2022 (around 1.77 million). A detailed list of the unused animals killed by species can be found in Table 48 of the report. The collection of these data results from an amendment to the Laboratory Animal Reporting Ordinance, which entered into force in August 2021. Since 2021, Germany has been collecting data on unused and killed laboratory animals on an annual basis, thus going beyond the requirements of the European Commission, which only requires to survey these numbers for EU-wide publication every five years. The most recent publication of this data by the European Commission was in 2024 and contained the data for the 2022 reporting year (EU report). The current data for Germany for the 2022 reporting year has already been submitted to the European Commission and will be included in the European Commission’s next report. With its decision to publish these figures on an annual basis, Germany seeks to ensure the greatest possible transparency in addressing the topic of animal experiments and is therefore assuming a leading role within the EU. 

Table 1: Total number of laboratory animals used in research, as well as animals killed for scientific purposes or animals killed and not used in 2022 and 2023

¹⁾ Animal experiments pursuant to TierSchG section 7(2)
²⁾ Animals killed for the sole reason of using their organs or tissue for scientific purposes (pursuant to TierSchG section 4(3))
³⁾ Animals bred for scientific purposes that were killed without being used for such purposes (pursuant to Section 1 Para. 1, Sent. 1, No. 1a of the German Laboratory Animal Reporting Ordinance (VersTierMeldV)). Figures for these animals were first collected as part of annual laboratory animal reporting in the 2021 reporting year.

Animal species used

Overall, the numbers for animals that were used in experiments in 2023 have decreased compared with the previous year (Figure 1 and Table 2). However, no striking changes were observed in terms of percentages. Comparably with the previous years, mice accounted for 73% of the animals used while rats accounted for around 7%. As in the previous year, fish (zebra fish and other fish species) were the second most frequently used laboratory animal species at 11%. As in 2021, the proportion of rabbits (approx. 5%) has increased by less than 1% compared to 2022. The proportion of birds (domestic fowl and other bird species) has remained at a consistently low level at around 1%. At 3%, the proportion of other laboratory animals is slightly lower than the previous year. The exact numbers for other animal species, broken down according to first-use and re-use, can be found in Table 21 of the report.

Figure 1: Numbers and proportions of animal species used in animal experiments in 2023 (pursuant to TierSchG section 7(2)). For a larger version of this image, please click here (91.8 KB).

Table 2: Comparison of the numbers and proportions of animals used in animal experiments in 2022 and 2023 pursuant to TierSchG Section 7 Para. 2.

 


Figure 2: Numbers and proportions of animals killed for scientific purposes in 2023 (pursuant to TierSchG section 4(3)). For a larger version of this image, please click here (91.9 KB).

Mice (86%) and rats (7%) account for the vast majority of animals killed for scientific purposes (see Figure 2). The third and fourth places in this ranking are occupied by fish (around 5.5%) and birds (around 1%). Rabbits and other animal species together account for less than 1% of animals used. Killings for scientific purposed are primarily (around 92%) carried out for basic research. A detailed breakdown (by species) of animals killed pursuant to TierSchG Section 4 Para. 3 can be found in Tables 47-47.2 of the report.

Figure 3: Numbers and proportions of animals killed and not used in 2023 (pursuant to VersTierMeldV Section 1 Para. 1, Sent. 1, No. 1a). For a larger version of this image, please click here (92.3 KB).

Figure 3 presents the proportions of animal species for animals bred for scientific purposes and killed without being used for these purposes. Once again, mice make up the greatest proportion, at just under 86%. Fish form the second largest group, at around 12%. Rats and xenopus follow in third and fourth place with just over 1% each. Rabbits, birds and other animal species together account for less than 1%. The overwhelming majority (around 86%) of animals killed and not used were derived from breeding of genetically modified animals. As 78% of the animals were themselves genetically modified, these numbers likely mostly account for genetically modified (sibling) animals which did not have the modifications necessary for experimentation. A detailed breakdown (by species) of animals killed for other reasons can be found in Tables 48-48.2 in the report.

Development of the numbers since 2020

Since the 2021 amendment to the Laboratory Animal Reporting Ordinance, the BfR has collected and published the annual animal experiment numbers. The first reporting year published by the BfR was 2020, a year shaped by the Coronavirus pandemic. In the reporting year 2020, compared with the precious year, the number of animal experiments decreased by around 16% and the number of killings for organs and tissue decreased by around 10%. In total, there was thus a strong decrease in the use of laboratory animals of almost 13% (see Figure 4). Since then, the total number of uses has continued to decrease, albeit not as much. Compared with 2022, the almost 13% decrease in the use of laboratory animals in the current reporting year, 2023, is remarkably more on par with the level of decrease from 2020 (see Figure 4).

The number of animals killed and not used also decreased in the reporting year 2023. The 22% decrease was not as pronounced as in the previous year (approx. 31%), but it amounts to a reduction of almost 400,000 killings of laboratory animals compared to 2022.

Figure 4: Development and two-year comparison of the animal numbers since the reporting year 2020. For a larger version of this image, please click here (92.5 KB).

Use of monkeys and prosimians

The number of monkeys and prosimians used in animal experiments, 1676, decreased from the previous year by 24% and thus achieved a record low. However, the number of used monkeys has been subject to a high degree of variance over the past years. The number also decreased when viewed over the last five years. For instance, it is almost half (49% decrease) of what it was in the 2018 reporting year. In monkeys and prosimians, the proportion of re-used animals is also high compared with other animal species (approx. 11% re-use compared with approx. 2% in mice and rats (see Table 21 in the report)). At 1,489 animals, the number of first-use monkeys and prosimians recorded for 2023 is therefore lower than the number of animal uses reported (1,676). Monkeys are mainly used for regulatory purposes, for instance for authorising medicines for human use. Great apes were last used for scientific purposes in Germany in 1991.

Use of dogs and cats

The use of dogs and cats include legally required experiments and applied research. In the 2023 reporting year, 2,550 dogs were reported as used in experiments, 11% less than the previous year (2,873 uses). In contrast, the number of cats used in experiments, 544, remained essentially stable (2022: 538 animals used in experiments). The annual number of dogs and cats used in experiments fluctuates comparatively strongly from year to year. However, looking at the last five years, it can be said that the number in 2023 was below the average of the last five years for both dogs and cats and thus denotes an overall decrease. In dogs and cats, the proportion of re-used animals is also very high at 57% (dogs) and 51% (cats) (see Table 21 in report). For this reason, the number of animals recorded for the first time is also significantly lower than the number of animals used in experiments. In 2023, 1,100 dogs and 269 cats were registered for the first time in Germany.

Use of fish (zebrafish and other fish species)

In 2023, 161,713 fish were used in animal experiments pursuant to TierSchG section 7(2). The figure for these animals has therefore decreased greatly compared to the previous year (212,371 uses). Since the 2019 reporting year, more fish were used in experiments (347,543 animals in 2019, an 81% increase compared to 2018). Since then, the numbers have been steadily decreasing. In the current 2023 reporting year, the numbers fell to below the 2018 level (192,040 animals) for the first time.

Use of genetically modified animals

Compared with the 2022 reporting year, the absolute number of genetically modified laboratory animals decreased by almost 20% in 2023 (see Table 3). Overall, 738,066 genetically modified animals were used in experiments – around 180,210 fewer than in the previous year (918,276 animals). In 2023, the proportion of genetically modified animals among the overall number of animals in experiments was 50.6%. Thus, like in 2021-2022 more genetically modified animals were used than non-genetically modified animals in the 2023 reporting year. However, in the previous year, the proportion of genetically modified animals was 53.2%. The proportion of modified animals with and without a pathological phenotype remained almost the same compared to the previous year; roughly one in five genetically modified animals exhibited characteristics detrimental to the animal’s well-being (see Table 3). Mice (87%) and zebra fish (12%) account for almost all of this category (see Table 20 in report for a more detailed breakdown).

Severity of the experiments

Most of the animal experiments conducted in 2023 were categorised as causing mild pain, suffering, or harm (63.8% of animals used experiments, see Figure 5). Following an increase in 2022, the proportion is thus back down to the level from two years ago (63.2% in 2021). At 27.5%, the proportion of experiments with moderate severity increased by around 2%. At 3.5%, the proportion of experiments where animals experienced a severe impact on their well-being reached the lowest point of the previous years. As in the previous years, the proportion of animals used in experiments that were carried out under general anaesthesia from which the animals did not wake up (non-recovery) accounted for around 5% of uses. Tables 22-34 of the report present detailed lists of severities by experimental purpose and species used.

Figure 5: Severity of the experiments carried out in 2023 in accordance with Section 7 Para. 2 TierSchG, shown according to numbers of animals and proportions. For a larger version of this image, please click here (92.2 KB).

Scientific experimental purposes

Although many questions in science can now be answered by utilising cell cultures, organoids, organ-on-a-chip systems, computerised processes and other alternative methods, we cannot yet dispense with the use of animals for scientific purposes – including their use in medical research. Around 59% of animal experiments related to basic research. Compared with the figure for 2022, the proportion of laboratory animals used in basic research increased by around 3%. About 14% of the animals were used as part of research into human and animal diseases (Figure 6).

Roughly 17% of the animals were used as part of production and quality control processes for medical products or for toxicological safety testing. Around 6% of the animals were required to maintain colonies of established, genetically modified animals and could not be utilised in other experiments. The number of these animals was reduced by around 55% compared with the 2022 reporting year.

Other experimental purposes, such as to maintain or protect species, for educational purposes or training of vocational skills, or to protect the natural environment, made up around 4% of all experiments. A detailed presentation of animal numbers broken down by individual experimental purpose is given in Table 9 in the the report.

Figure 6: Percentage breakdown of the laboratory animals used for the respective experimental purposes in 2022 and 2023. For a larger version of this image, please click here (90.9 KB).

Animal experiments in basic research

In 2023, investigations conducted into the immune system (21%) and the nervous system (19%) accounted for many of the experiments conducted in basic research. These numbers have not changed substantially compared with the previous year (see Table 4). Greater increases were only found in the area of research into the urogenital and reproductive systems. The number of laboratory animals used for these purposes increased by around 81% compared with the previous year. Detailed information, for instance pertaining to the distribution of animal species across the various purposes with basic research, can be found in the report.

Table 4: Laboratory animals used in basic research in 2023, by experimental purpose. 

Animal experiments in translational and applied research

As in the previous year, applied research into disease in 2023 focused on cancers in humans. There were greater increases in the area of development of therapies against diseases of the human urogenital system as well as against cardiovascular and respiratory illnesses (see Table 5). Compared to the previous year, the number of laboratory animals used for research into animal diseases was reduced by more than half. Detailed information, for instance pertaining to the distribution of animal species across the various purposes with translational research, can be found in the report.

Table 5: Laboratory animals used in translational and applied research in 2023, by experimental purpose. 

Review: Animal experiment figures from 2009 to 2020

The BfR first published data collected in accordance with laboratory animal reporting in 2020. The reported figures can be accessed here.

The website of the German Federal Ministry of Food and Agriculture (BMEL), which was responsible for the publication of the data at that time, provides a presentation of the use of animals in animal experiments from 2009 to 2019 as well as detailed comparative data. 

Go to animal experiment 2009-2019

Activities promoting the ‘3R’ principle (replacement, reduction, refinement) 

The Federal Republic of Germany endeavours to reduce the number of animals used in experiments. For this reason, various measures are being taken to replace animal experiments with alternative methods to animal experiments as quickly as possible. These include scientific measures that are implemented and promoted by the German Centre for the Protection of Laboratory Animals (Bf3R) at the German Federal Institute for Risk Assessment (BfR). Measures also include research financed by the Foundation for the Funding of Research into Alternative and Complementary Methods to Restrict Animal Experiments (set), various funding measures from the German Federal Ministry for Education and Research to develop alternative methods to animal experiments, and the annual award of the Animal Welfare Research Prize by the BMEL. 

Background information on the collection of laboratory animal data

The EU Directive 2010/63/EU entered into force on 9 November 2010. Its transposition into national law in 2013 also necessitated a revision of the Laboratory Animal Reporting Ordinance with a broadening of reporting obligations for the use of laboratory animals. Since then, reporting is also required on the use of cephalopods (e.g. squids and octopuses) and vertebrate larvae, as well as the breeding of genetically modified animals. In addition, the severity of the overall pain, suffering or harm (non-recovery, mild, moderate, severe) to which the animals are exposed as a result of their use must also be reported. The recording of animal use in experiments in compliance with these new requirements was undertaken for the first time in 2014. On 11 August 2021, the Laboratory Animal Reporting Ordinance was amended to include a requirement to provide annual figures on the numbers of animals reared for scientific purposes and killed without being used for such purposes. Data for this figure of ‘killed and not used animals’ was first collected for the 2021 reporting year.

Since 2021, the European Commission has maintained a searchable and freely accessible database on laboratory animal statistics (see Article 54 of the EU Laboratory Animal Directive 2010/63/EU). The ALURES Database contains statistical data on the annual use of laboratory animals within the European Union. An explanatory video is also provided there that contains detailed instructions on how to use the database.

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