Discomfort during animal testing

In most studies the laboratory animals suffer mild or moderate discomfort. Where possible, we try to reduce discomfort, for example by choosing advanced humane end points, best housing, better test methods or the use of analgesia. In a limited number of studies, animals are anesthetised for the purpose of the study, without the necessity to awaken them. This way, discomfort of these animals can be kept to a minimum. Internationally, this type of study is classified as ‘Terminal’. For TNO, the number of ‘terminal’ animal experiments comprises 0.6%.

All other animal experiments are classified as mild, moderate or severe.

AAALAC (Association for Assessment and Accreditation of Laboratory Animal Care) is a worldwide accepted organisation that aims to optimise animal welfare through a voluntary accreditation and assessment programme that extends beyond the minimum regulatory requirements for animal testing.

MILD discomfort (62% of animal tests)

For some studies animals must be fed a special diet, such as a high or low-fat diet, which cause no inconvenience. This type of test may be a treatment that is categorised as 'mild discomfort'. TNO aims to reduce the number of animals needed by choosing an optimum statistical design and combining control groups where possible.

Moderate discomfort (37% of animal tests)

For other studies the animals are injected with the substance under investigation on a weekly basis over an extended period, or light surgery is performed under anesthesia. If possible, procedures are combined to reduce the number of animals subject to such intervention. Painkillers are also used for animals that undergo light surgery. Such experiments come under the ‘moderate discomfort' category.

Severe discomfort (0.7% of animal tests)

Testing the efficacy of drugs involves testing the potential new drugs in animals in which specific symptoms are induced, which may result in ‘severe discomforts' in the animal. For example, TNO tests new drugs for lung fibrosis. In these studies we choose the earliest possible experimental end point to ensure that the test can be stopped as soon as acceptable results are achieved.