Advisory report: Genetically modified animals killed in stock

The term ‘killed in stock’ is often used by the Dutch animal research field. This concerns animals that are euthanized without having been part of an experiment. A distinction is made between: 1) animals that died or were killed after being used for breeding (e.g. parent animals used for breeding); and 2) animals that died or were killed before being used for breeding or animal experiments.

In the past ten years, there has been a sharp rise in the number of animals reported as “died or killed in stock” by the Netherlands Food and Consumer Product Safety Authority (NVWA). This increase can be attributed to the use of genetically modified (GM) mice and zebrafish. Increases in the use of GM animals (particularly in biomedical research) and in the number and range of complex hybrids, along with advances in the technology for creating GM animals, account for the reported increase.

In 2015, at the request of the then State Secretary of Economic Affairs, we issued an advisory report on reducing of the number of GM animals ‘Killed in stock’, with a particular focus on fish and mice (Part 1). The advisory report describes which quality and efficiency criteria could contribute to a reduction. A leading example here is the appointment of breeding coordinators to monitor the quality and use of the technology applied to laboratory animals.

In order to improve the quality of the generation and breeding of genetically modified animals in the Netherlands, we issued a supplemental advisory report (Part 2) in 2018. The aim of this report was to make the involved parties aware of the specific, defining moments at which it is possible to reduce the number of animals killed before they are used in breeding or animal experiments. This report includes quality and efficiency criteria that can contribute to achieving this reduction. These criteria also serve as a guidance for making properly substantiated decisions. The report contains two Codes of Practice, being the ‘CoP for the generation of genetically modified animals’ and the ‘CoP for breeding of GM animal models’.