Travers, A., Thomson, J., Sharp, M. 2019. Refining mouse re-derivation by using in vitro fertilisation (IVF) with fresh or frozen sperm as opposed to embryos. Animal Technology and Welfare 18(1), 73-74.

To attempt to reduce, refine and replace, we have employed a several new approaches to rederive mouse strains. By using in vitro fertilisation (IVF) with fresh or frozen sperm we can reduce the timeframe and number of animals required to re-derive a strain. This method of importation also reduces the stress on animals by reducing the need to transport live animals. Using sperm and IVF to re-derive mouse strains instead of embryos is a great technological initiative because: 1) Reduction: Large scale breeding is not required to produce 1 or 2 sperm donors. 2) Refinement and Replacement: It has a positive impact on the welfare of the animals, by replacing the need to import live animals (in some cases). 3) Reduction: The timeframe for re-derivation is Reduced by 50% which saves money, time and resources. 4) Reduction: We now have the opportunity to rederive animals with an unacceptable pathogen load for import into our units. This helps the research community vastly. The only alternative before would have been to remake the animals by pronuclear microinjection or ES cell injection.