The pups were individually weighed and monitored for general behaviour and reactivity, health, sensory and muscle development, and reflexes on day 1, 3, 7, 14 and 21 of age following a protocol based on pre-weaning development stages and adapted from [20] and [21] . Additionally, from day 13 onwards pups were weighed every second day and screened daily to detect the day when both eyes were opened. During scoring the adult female was removed from the home cage and placed into an empty opaque cage, food and water being provided. Specifically for the respective monitoring days, the following records were taken: Day 3: presence/absence of a milk spot and the position of the animals regarding the nest (inside/outside). Righting reflex: the pup was positioned in dorsal recumbence and the time it took to turn to a ventral position was taken with a cut off time of 60 sec.