502
ENCWALL AND KRISI al
between their own and the donor placenta: the aversion
conditioned to donor placenta (surgically removed) general-
ized to their own placenta (normally delivered).
Experienced females, on the other hand, had consumed
placenta during their first parturition, which had occurred
before the induction of the aversion; primiparae had the
opportunity to develop learned safety to placenta prior to
TAC. Although an aversion to donor placenta was acquired
by nonpregnant primiparae, they did not express the
aversion to their own normally-delivered placenta at the
subsequent parturition. They did express an aversion,
however, to donor placenta presented immediately after
parturition. The primary effect, therefore, of prior parturi-
tional experience seems to have been to enable the
primiparae to distinguish between their own and donor
placenta (or perhaps between normally-delivered and
surgically-removed placenta) as evidenced by the ease of
inducing TAC and by the difference in response between
the Parturitional observation and the immediately-
postpartum test.
In Experiment 3, TAC occurred immediately after
delivery in primiparae, rather than in a nonpregnant state.
The potential for expression of the aversion during a second
parturition may have been enhanced by conditioning and
testing the aversion under the same conditions (i.e.,
parturition). The results of Experiment 3 indicate that if.
during the first parturition, unpaired ingestion of placenta
prior to TAC is prevented, then a single pairing of placenta
with LiCLinduced illness can reduce the incidence of
Placentophagia during the second parturition.
The aversion induced to normally-delivered placenta, in
Experiment 3, was expressed when fresh normally-delivered
placenta was available, such as al delivery and during the
immediately-postpartum test (the stimulus for this test was
normally-delivered placenta only in Experiment 3), but not
when frozen and thawed normally-delivered placenta was
available in the test that occurred 44 days after TAC. The
response at 44 days may have been due to a recovery from
the aversion, may have reflected a discrimination between
fresh and frozen term placenta, or may have been due to
the fact that the 44 day test did not occur when the female
was parturient. The present design cannot discriminate
among these alternatives.
As determined by Observationsofconcomitant maternal
behavior, conditioned aversion to placenta appeared not to
cause severe disruptions in the sequencing of maternal
behavior. The aversion appeared to modify only the
ingestion of placenta, leaving pup-licking, removal of the
umbilicus and amnion, retrieval, and nest-building, intact.
The partial or complete absence of placentophagia during
parturition did not appear to prevent the female from
providing adequate, though broadly defined, maternal care.
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