Body mass and attractivity of female offspring are negatively affected by food restriction of meadow vole (Microtus pennsylvanicus) dams during lactation

The environment experienced by pups during lactation (nutrition and maternal behaviour) can contribute not only to sexual development, but also to individual differences in offspring sexual behaviour. We tested the hypothesis that female offspring of meadow vole dams (Microtus pennsylvanicus) that were 30% food restricted (FR) during days 1-7 of lactation (FR 1-7), days 8-14 of lactation (FR 8-14), or days 15-21 of lactation (FR 15-21) show negative effects on their food intake, growth, and the three components of sexual behaviour (attractivity, proceptivity and receptivity) as compared with female offspring of control dams. With the exception of age 29 days or age 34 days, the body weights of female offspring of FR 1-7 dams and FR 8-14 dams between days 21 and 48 were lower than the body weights of female offspring of FR 15-21 dams and those of control dams. Female offspring of FR 1-7 dams maintained a lower body weight than the other female offspring throughout the study. Female offspring of FR 8-14 and FR 15-21 dams produced odours that were less attractive to males than odours produced by those of FR 1-7 and control dams. Female offspring of FR dams and control dams did not differ in their measures of proceptivity and receptivity. However, the total amount of time allocated for copulation by males was shorter for those males that were paired with female offspring of FR 1-7 dams than it was for those that were paired with the female offspring of FR 8-14, FR15-21, and control dams. The results of this study, coupled with those found in a study conducted on the male offspring of FR dams, indicate that for female offspring days 1-7 and for male offspring days 8-14 of lactation are the time periods during which food restriction of dams had the greatest impact on deficits in sexual behaviour and body mass in meadow voles