A simple method for short-term maintenance of neonatal mice without foster mothers.

Mice are typically weaned from their mother between 21 and 28 days of age, or at 10 grams of body weight. However, some biochemical experiments need to be done before the weaning days, and the mother might cannibalize or ignore those manipulated pups. Here, we provide a detailed protocol for maintenance of neonatal mice without the presence of their mothers for biomedical research. The basic instinct of neonate mice to hide under covers is harnessed for their survival in a mother-free environment. When covers are soaked with milk and the only targets for hiding, the neonates would acquire their nutrients at least in an involuntary fashion. The protocol is simple and can be used for neonatal rodent studies for short periods of times, and assures the accuracy of the biomedical experiments if survival rate of neonates is critical.