The effect of experimental termination of lactation on subsequent growth in Peromyscus leucopus
The effect of length of the lactation period on subsequent postnatal growth was examined in the white-footed mouse, Peromyscus leucopus. Litters were separated from the mother at 19, 20, 21, 23, and 25 days after birth. Some individuals in each group lost mass during the 24-h postseparation period, and animals in all treatments showed a significant decline in postnatal growth rate during this period. Average litter growth showed no long-term effect from the timing of mother–offspring separation, with no significant treatment effects after 25 days of age. The timing of mother–offspring separation affected male and female offspring differently, with female offspring mass at 42 days being lowest for females separated later. The timing of mother–offspring separation also affected maternal reproduction such that the timing of weaning was positively correlated with the length of the gestation period of litters conceived at postpartum estrus.