AN EFFECT OF COLD EXPOSURE AT BIRTH ON THE REPRODUCTION OF MICE

Abstract

Mice of strain A2G/Tb, of a stock adapted to an environment kept at -3[degree]C, were fostered shortly after birth on to A2G/Tb mice breeding at 21[degree]C. The parents of one group (a), were transferred to 21[degree]C before the birth of a litter; those of a second group (b), were left in the cold. The group (b) young, which were exposed to cold for a few hours after birth, were heavier at 10 and 21 days than those of group (a). Mice of both groups were mated: those of group (b) had a lower death rate among their nestlings than those of group (a). Offspring of group (b) were also mated; the mortality among their nestlings resembled that of group (a) nestlings.