Objective To study the effect of dopamine receptors on neurological and physiological activities. Methods Dopamine D1 receptor gene (DRD1) knockout mice and dopamine D3 receptor (DRD3) gene knockout mice were introduced, and double gene knockout mice were bred in our lab. Seven SPF male mice in each group were used in this experiment. The food intake, water intake, body weight gain for 24 hours were tested on the age of 30 d, 50 d, and 70 d and were compared with those of wild type mice. Results DRD1 gene and DRD3 gene showed significant effect on the body weight in mice in age of 21 day and 35 day, but at the age of 90 day, the differences became insignificant among the mice of various genetypes. Conclusions Dopamine may effect on the foraging and satiety in newborn mice through regulating the hypothalamic-pituitary-adrenal (HPA) axis activity, and finally leads to a reduced body weight gain in newborn mice and puppies during lactation. Furthermore, DRD1 gene and DRD3 gene may influence on body weight of newborn mice through regulating mothers' lactation, lead to a lower body weight at ablactation, and compensatory increase of body weight after ablactation. Our results provide a substantial foundation for studying the function and interaction of DRD1 and DRD3 genes.