This study used a litter cross-fostering approach to measure milk production and maternal performance. Males and females of each inbred strain were mated, allowing females to complete lactation with their first litter. Females of each inbred strain were then mated with CD-1 males. Biological pups were removed, counted, and replaced with ten neonatal CD-1 pups (day 1), which were weight- and size-normalized. Dams and pups were studied for eight days. Average daily weight gain of litters served as the primary indicator of milk production. The number of pups surviving served as a related indicator of maternal performance.
|Summary of procedures that were conducted|
|• colony observation
|• body weight