The effects of strain, reproductive condition, and strain of placenta donor on placentophagia in nonpregnant mice

The effects on placentophagia of strain, reproductive condition, and strain of placenta donor were observed in nonpregnant mice. Mice of the C57BL/6By and BALB/cBy strains were exposed to placentas of either strain after either no previous parturitional experience, one parturitional experience without nursing experience, or one parturitional experience with nursing experience. There was a significant effect of strain, a significant effect of reproductive condition, but no significant effect of strain of placenta donor. There was a significant interaction between strain and reproductive condition, but no significant interactions with placenta strain. It was inferred that the ability of a mouse to acquire and utilize relevant stimuli during and after parturition, in order to produce an emancipation of placentophagia from the physiological controls associated with parturition, is influenced by genotype.