Placentophagia in rabbits: incidence across the reproductive cycle

Rabbits show placentophagia at parturition, but the regulation of this behavior and its incidence across the reproductive cycle are unknown. By testing estrous, midpregnant, prepartum (day 1), and postpartum (days 1 and 5) food-deprived rabbits with liver and placenta, we found an absence or infrequency (<%) of placentophagia in the former three groups, an invariable occurrence at parturition, and a persistence into postpartum days 1 and 5 (50 and 48%, respectively). Most placentophagic females also ate liver on postpartum day 1, but not on postpartum day 5. In different food-deprived rabbits, tested every 2 hr with placenta and food pellets, placentophagia incidence was 20% at 8 hr prepartum, 100% at parturition, and 67 and 21% at 8 and 24 hr postpartum, respectively. Most placentophagic rabbits also ate food pellets in postpartum (but not in prepartum) tests. Results suggest that somatosensory, hormonal, or both factors of the peripartum period regulate placentophagia expression.