Neonatal nutrition through mother’s milk may be an important environmental factor in rats. Therefore, milk content should occasionally be measured to analyze its quality, but it is difficult to obtain sufficient amounts of rats’ milk for analyses. In this study, we developed a new device for sampling milk from rats and used it to evaluate dietary effects during pregnancy and lactation on the growth performance of pups. In addition, certain substances （carp gallbladder extract and pumpkin heated water extract） were given to pregnant Wistar rats and their effects of stimulating mother's milk secretion were examined. Milk samples were obtained using the newly developed device on the 7th, 14th, and 21st postpartum days. The body weights of dams increased during pregnancy, but the milk volume and body weight （pups） were not significantly different. These findings suggest that the above-mentioned dietary supplementation during pregnancy and lactation may not improve milk quantity, but it is necessary to optimize this newly developed device further, even though the milk yield obtained in the present study was adequate.