Animal experiments: Figures and Statistics

Rodents, chickens, and other livestock animals are the types of animals that are typically used for experiments at the University of Hohenheim. In 2022, around 85 percent of the animals used in experiments were used in animal experiments with a low severity classification. Around 9 percent of the experimental animals were used for experiments in which the animals are killed, for example in order to remove their organs for research purposes.

A more detailed overview of the scope of animal experimentation at the University of Hohenheim can be found in the official experimental animal report. There, the university reports each experimental animal that was used in an experiment or which was killed for the purpose of organ removal.

Some experimental animals – especially livestock animals – are used repeatedly for experiments over a period of several years.

Contact

Florian Klebs
Press, Internal Communication, and Social Media Staff Office
Director
+49 (0)711 459 22003
email

Experimental animals

The most commonly used experimental animals according to the 2022 experimental animal report were chickens, followed by sheep, mice, rats, and frogs.

With chickens, the University of Hohenheim investigates the make-up of ideal feed and evaluates new feed sources as alternatives to imported grain (environmental protection and lower use of resources), as well as the basics of interactions between the animal and microbiome in the digestive tract. The question of how to prevent feather pecking (animal welfare) is also one of the research questions that were addressed.

With mice, the university looks at human nutrition (especially for disease prevention / health), immune reactions, and other biological issues.

Many other studies on farm animals do not require the use of experimental animals because data from farms or slaughterhouses is used.

Severity classification of animal experiments

Pie chart: Mild Severity 70,2 %, Moderate Severity 14 %, Severe Severity 0,0 %, No restoration of vital functions 1 %, Killes for organs and/or tissue removal 14,7 %

Drawing blood from lambs to promote the breeding of robust pasture-fed lambs or fitting EEG sensors to pigs to evaluate new, non-invasive methods: Experiments like these are not very stressful for the animals. In the animal experiments registered in 2022, around 85% of the animals were used in experiments like these.

Experiments with a mid-level severity classification are e.g. those in which wild dormice are caught and marked.

In 2.6% of the experimental animals reported in 2022, the animal did not recover consciousness, e.g. after an experiment was carried out under anesthesia. A further 8.8% of laboratory animals were killed in order to remove organs or tissue such as muscles, nerves or digestive organs for research.

How stressful an experiment is for an animal is defined in EU Directive 2010/63/EU, Annex VIII “Severity Classification of Procedures,” where the criteria are illustrated with practical examples.

Reason for animal experiments

Pie chart: Research 94.0 %, Teaching 2.6 %, vocational training and further education 1.9 %, other 1.5 %

In the animal experiments registered in 2022, around 95% of the animals were used in research.

Around 1.76% of the animals were used for experiments in student education and training. These include two compulsory courses in the Biology and Agricultural Biology Bachelor’s degree programs. A further 1.6% were used in professional education and training.

The category “animal experiments for other purposes” is for e.g. experimental animals that are used to maintain specially bred colonies. These are e.g. mice that are genetically engineered so that they can serve as models for many human illnesses to research causes of diseases and treatments.

Overview of registered experimental animals in 2023

Severity classification

Species	Number	Mild %	Moderate %	No restoration of vital functions %	Euthanized for organ/tissue removal %
Domestic chickens	3,126	92.5	0.3	0.0	7,2
Mice	627	19.5	39.9	0.0	0.0
Dormice	352	0.0	100.0	0.0	0.0
Rats	189	2.1	0.0	0.0	97.9
Clawed frogs	34	50.0	100.0	47.1	2.9
Gerbils	18	100.0	0.0	0.0	0.0
Pigs	8	100.0	0.0	0.0	0.0
Cows	14	100.0	0.0	0.0	0.0
Total	4,368	70.2	14.2	0.8	14.7

Reason for experiments

Species	Number	Research %	Teaching %	professional training/ education %	Other* %
Domestic chickens	3,126	100.0	0.0	0.0	0.0
Mice	627	61.1	15.9	12.4	10.5
Dormice	352	100.0	0.0	0.0	0.0
Rats	489	97.7	2.1	0.0	0.0
Clawed frogs	34	88.2	2.9	8.8	0.0
Gerbils	18	44.4	55.6	0.0	0.0
Pigs	8	100.0	0.0	0.0	0.0
Cows	14	100.0	0.0	0.0	0.0
Total	4.368	94.0	2.6	1.9	1.5

* Other: Maintenance of colonies of established genetically modified animals that are not used in other processes.

Source for graphics and table: Experimental animal report 2022

Unusable (so-called “surplus”) experimental animals

Animals for animal experiments at the University of Hohenheim are purchased from specialized laboratory animal breeders or bred at the University itself.

In some cases, there are very specific breeding objectives for this breeding, as a laboratory animal can often only be used for an animal experiment if it has certain characteristics. This is particularly true in the case of genetically modified mice which are predisposed to particular diseases, for example. However, there are also animal experiments for which, for example, only male or female animals can be used.

If the breeding of laboratory animals also produces offspring that cannot be used for an animal experiment due to their characteristics or sex, these are referred to as surplus laboratory animals.

The University of Hohenheim has established a series of measures to avoid surplus animals as far as possible.