Caring for the mothers: the impact of breeding on female mice
The research group will conduct a comprehensive assessment of maternal welfare, including an analysis of the dams’ behaviour, metabolism and nutrition.
In Switzerland, 62 percent of laboratory animals are mice, with more than 346,000 mice used in 2020. Research teams assume that these animals come from healthy mothers, or dams, but is that really the case? "The dams are the unsung workhorses of animal research, but we know relatively little about their health and wellbeing," says Christina Boyle of the University of Zurich, who is leading the NRP project in question. Breeding practices, she says, are designed for maximum productivity, not maternal health.
How do these practices affect the mother and offspring? What are the critical factors – the number of pregnancy cycles, nutrition, litter size, time of weaning? When mouse breeding pairs are housed together permanently, the female is often impregnated hours after giving birth, leaving her body to contend with the conflicting demands of pregnancy and lactation. What effect does this have on the offspring in the first litter? And are the effects compounded over multiple reproductive cycles?
"Our project sets out to answer these questions. As far as we are aware, we are the first group to investigate the impact of breeding on mouse dam welfare," says Boyle. The research group will conduct a comprehensive assessment of maternal welfare, including an analysis of the dams’ behaviour, metabolism and nutrition, and compare the data they obtain with data from non-breeding female mice.
The goal of this project will be to generate a new level of transparency regarding experimental breeding practices. The findings may also be used as a basis for introducing more structured guidelines or regulations for breeding management – stipulating, for example, whether breeding dams should have a recovery period between reproductive cycles.
Impact of current breeding practices on the health and wellbeing of the breeding mouse dam