Animal experiments in Switzerland

3. Four severity grades

In Switzerland, animal experiments are classified into four stress categories – of so-called severity grades. Severity grade 0 means the animals are not exposed to any stress. Observation studies are an example of this. Almost half of laboratory animals in Switzerland are used in severity grade 0 experiments. Severity grade 1 corresponds to mild stress (e.g. blood sampling)and severity grade 2 to moderate stress (e.g. surgical procedure under anaesthesia). Highly stressful animal experiments (severity grade 3) are only used for serious diseases such as multiple sclerosis or rheumatoid arthritis. Experiments of this kind are reduced to a minimum and are only carried out and approved if no alternatives are available. In Switzerland, fewer than 3% of all animal experiments were classified as severity grade 3 in 2018. In these studies, 95% of the animals were mice and rats.

A severity grade is always assigned before the start of the experiment (prospective classification). The researchers must give the highest possible stress that could occur during an experiment. After the study, the experiments are evaluated and each animal is assigned the severity grade that it actually experienced in the experiment (retrospective classification). In the autumn of 2018, the Federal Food Safety and Veterinary Office (FSVO) published new guidelines for the prospective assignment of severity grade to an animal experiment. In these guidelines, for example, the severity grade for experiments in brain research (neurodegeneration as in Parkinson’s) was raised from 2 to 3.