Welfare of laboratory animals

The use of laboratory animals for necessary purposes in research and education, implies keeping animals, and sometimes also breeding and manipulating them. Ghent University attaches great importance to the welfare of animals used for testing. Here, the term ‘welfare’ refers to the conditions as experienced by the animal itself.

Pain and other discomfort

When animals are negatively affected by their enclosures, treatment, or other circumstances, this can take different forms. Types of discomfort may include, for example, pain, suffering, fear and/or permanent physical or mental damage.

The degree of discomfort is an important factor in animal testing, and this is governed by explicit legislation. According to the law, not all practices are considered to be animal tests. For example, bird ringing is not an animal test. Belgian and European animal testing legislation defines animal testing as any procedure that causes as much, or more, discomfort as introducing a needle in accordance with good veterinary practice. It is not always easy to estimate, quantify or compare levels of discomfort. After all, there are the many different forms of discomfort, including pain, suffering, anxiety and permanent damage, but also itching, social containment (i.e. related to group size or group composition), physical containment (for example, the size of the enclosure), physiological containment (i.e. related to the impact of some studies in nutrition, or the impact of medication or interventions) and behavioural containment (for example, an animal facing a lack of control, or an unpredictable situation).

Welfare and animal enclosures

Laboratory animals spend most of their time in their enclosures. As far as possible, these are kept separate from the locations where tests or other handling takes place. An animal caretaker checks the enclosures every day, while a veterinarian regularly does an additional inspection round.

Within the enclosures, an effort is made to ensure that the animal faces the lowest possible number of limits as possible (e.g. physiologically and in terms of behaviour).

Regarding the size of the enclosure, whenever possible animals are provided with more space per individual than is required by law, and in addition, it is also important to consider the size and composition of the group for social animals. For example, mice are not to be housed individually. However, whenever there is a problem (for instance, if a male behaves aggressively towards other animals), a veterinarian will decide on possible relocation or temporary isolation from the group. Increasingly, there is also an emphasis on prevention: for example, caretakers learn what signals mice might show in reaction to different forms of stress so that this is noticed sooner. This makes it easier to intervene in a timely fashion.

Depending on the needs of each species, other enrichment is provided, ranging from shelters, nesting material and gnawing sticks for mice; ‘toys’ such as balls for pigs; or offering food from the top of the cage so that rats, for example, are kept actively engaged. The key here is variety, since (with the exception of food), when it comes to enrichment, animals can become rapidly acclimatised.

Welfare in animal research and testing

If a researcher wants to launch a project involving the use of animals, he must assess in advance the degree of any possible discomfort of each test or other procedure, and justify this to the Ethics Committee on Animal Research and Testing, for whom this aspect weighs heavily in the evaluation of the application.

The level of pain or degree of severity of a test must be estimated and justified in advance. After the test, a mandatory retrospective analysis must be submitted to the Ethics Committee. So it is not in a researcher's interest to underestimate the potential degree of severity.

The degree of severity can be classed as ‘light’, ‘moderate’, or ‘severe’. These levels are defined under European legislation. Nevertheless, this remains a rather subjective assessment from the human point of view: it is not easy to estimate how something is experienced from the animal’s perspective. After the researcher consults with the Ethics Committee, the estimated degree of severity may sometimes be adjusted.

European law also defines a separate class of ‘terminal’ tests. These refer to tests where an animal will die during the procedure, undergoing a single, terminal procedure under general anaesthetic.

There are also restrictions on the re-use of animals. Here, the lead investigator has to demonstrate how they will ensure the welfare of the animals, setting out the names of the people responsible for following up on the animals, criteria and possible use of score-grids, pain relief, conditioning, etc. Any isolation of animals (which may be necessary e.g. for EEG’s) must be justified and kept to a minimum. In Belgium, what happens afterwards to laboratory animals (or animals intended for use in testing) is regulated under Article 30 of the Royal Decree of 29 May 2013. The Ethics Committee may authorise former laboratory animals to be put up for adoption, to be released back into their habitat, or be placed in suitable enclosures. This can happen on condition that the animal’s health allows for it, that there is no danger to public or animal health or the environment, and that measures have been taken to ensure animal welfare.

Refinement: one of the three R’s

Working to improve the conditions of animals both during research and outside are forms of refinement, which is one of the three pillars of humane animal research. Refinement refers to any methods and improvements that prevent or minimise discomfort in any form, while optimising animal welfare.

Here, animal welfare also goes hand in hand with the research objectives. After all, it is known that pain and suffering have consequences for animal behaviour, physiology and even immunology. These factors could thus also have an effect on the results of the research, which is also obviously not the intention.

Therefore, for each application for animal research or testing made to the Ethics Committee, an investigator has to explain what efforts will be made to minimise the potential discomfort they predict may happen.

Some examples of refinement are:

  • setting up enclosures in a way that allows species-specific behaviour to be expressed, in particular behaviour for which the animal has a strong inherent inclination, (e.g., nesting in mice)
  • the use of appropriate anaesthetics and pain relief to minimise pain
  • the use of learning processes to reduce laboratory animals’ stress when interacting with humans and when undergoing procedures. For example, learning to associate the presence and/or actions of humans with food rewards, training animals to perform certain desired behaviours in exchange for rewards such as standing on the scales (as an alternative to lifting animals). As these processes are often time-intensive, they are most often used in animals that are kept as laboratory animals for longer periods of time.