Newman, S., Woodley, S. 2019. Time’s up for tick-over colonies… Do we now need to maintain so many GA mouse lines? Animal Technology and Welfare 17(3), 155-157.

The practice of continually breeding lines to maintain them as a live resource either in-between studies or indefinitely “just in case” is common practice in many animal facilities. This process of “ticking over” colonies has historically occurred due to the unavailability or unreliability of archiving services, coupled to the economic cost associated with the processes. The advent of reliable sperm cryopreservation and associated recovery processes has now eliminated most reasons to not archive lines. The appointment of the Manager of Embryology Services within King’s College London (KCL) Biological Services, coupled with the technical support by the Animal Technologists, has permitted rapid and efficient archiving which in turn has led to the substantial reduction in “tick-over” colonies. Between September 2015 and October 2017 various subsidy incentives were offered to research groups resulting in over 350 lines being cryopreserved with 97 removed as a live resource. This is a significant ethical refinement as it is estimated to have prevented the breeding of an additional 4,000 mice per year. Other benefits include releasing of cage space for scientific research and the accommodation of new mouse lines. The culture throughout small laborator y animal establishments to maintain tick-over colonies has been successfully challenged by centrally subsidised and targeted archiving throughout KCL Biological Services Units (BSUs), which has in turn facilitated further scientific work. Ethically and financially incentivised archiving is a noteworthy indication of our commitment to implementing the 3Rs across King’s College London.