The name is absent

Placi ntophagia and i ∖sɪ i aversion Condiiioning

TABLE 2

DESKiN ΛND RESULTS OF EXPf-RlMENT 2: I AC TO PLACENTA
INDUCED IN NONPREGNANT PRIMIPARAE (PROPORTION OF
GROUP EXHIHITING PLACENTOPHAGIA)

*AII animals determined Io be placentophages in a pretest.

for each group is presented in Table 2. The difference
between the mean number of pairings in Experiments I and
2 was not significant, t (28) = 0.34. p>0.10. The prior
experience with placenta of animals in Experiment 2 did
not result in a greater number of pairings Io reach criterion.

Observations of Placentophagia at the Second Parturition

At the second parturition, 5 of the 7 animals in the
pregnant group (Group P) exhibited normal placentophagia
to their own delivered placenta. The remaining 2 animals
showed an aversion to their own placenta as indicated by
placentophagia scores of 0.46 and 0.33, with a mean score
of 0.40 r 0.06. Considered as a whole. Group P did not
show an aversion to their own placenta during parturition.
When parturient females were compared with Iheir pretest
levels of placentophagia, females in Group P did not show a
significant change in their response to placenta al parturi-
tion (see Table 2). Although 5 of the 7 parturient females
had eaten their own delivered placenta during parturition,
none ate donor placenta presented immediately after
parturition (p = 0.03. McNemar test).

Although comparisons between the primiparae in Exper-
iment 2 and the nulliparae in Experiment 1 revealed no
differences in the number of pairings to reach criterion,
differences were observed in the expression of the aversion
to naturally delivered placenta during parturition. Eemales
that had had prior parturitional experience were signifi-
cantly less likely to exhibit an aversion to Iheir own
placenta during a subsequent parturition (Group P; 5 of 7
ate) than were females that had no prior parturitional
experience (Group CP; 1 of 7 ate) (p = 0.05, Eisher test).

Observations of Maternal Behavior

During the perinatal period. 1 female (in Group P) that
exhibited an aversion to placenta failed to clean a large
number of pups in her litter. When observed at 2 days
postpartum, the female had lost 9 pups from her litter.
Eour other females each lost I pup. All the females
retrieved their pups, both after parturition and at 2 days
postpartum. All of the females built nests, nursed their
pupsand kept their litters in a single pile within the nest.

7>c<) n∙<^,<^,A Postpartum Test

Whereas 5 of the 7 females in Group P had eaten
placenta during parturition, only 3 ate donor placenta al 2
weeks postpartum. All 3 had eaten al parturition but not in
the immediately-postparluιn Iesl. I he number of animals
eating placenta during the 2 week postpartum lest was not
significantly different from the number eating Iheir own
placentas during parturition (p = 0.31. MeNemar test) nor.
partly due to the small group size, from the number eating
during the pretest (p = 0.06. McNemar test), nor from the
number eating during the immedialely-postpartum lest <∕> =
0.13. McNemar lest).

To summarize the effects of TAC on placentophagia in
the pregnant experienced group, al parturition, immedi-
ately after parturition, and at 2 weeks postpartum, the only
aversion observed was to donor placenta presented immedi-
ately after parturition.

Response of Nonpregnant Peniales

Three of the 8 animals in the experienced nonpregnant
group (Group P) ale placenta in the test after the first
control interval (30 days after conditioning). This propor-
tion is significantly lower than pretest level (p = 0.03,
McNemar test). Note that Placentophagesareexpecled Io
eat during retests, e.g.. Group CP in Experiment I.

The results of the first nonpregnant-interval lest for
Subgroup CP (Exp. I) and Group P (Exp. 2) were
compared. Seven of the 8 inexperienced females (Subgroup
CP) exhibited the aversion as compared with 5 of the 8
experienced remales (Group P). Although the trend was in
the expected direction, the difference was not significant
since the number of animals tested was small (p = 0.28.
Eisher test). I hus the effects of prior parturitional experi-
ence did not appear to alter the expression of an aversion to
placenta when the animals were conditioned and tested in
the nonpregnant state.

When tested after the second control interval (44 days
after conditioning). 7 of the 8 animals in the experienced,
nonpregnant group (Group P) exhibiteιl placentophagia.
Although this proportion is larger than that observed after
the first control interval (3/8). due to the small group size,
this increase was not significant (∕> = ().()6, McNemar test).
Group P did not differ significantly from Group P on the
44 day lest (p = 0.26, I isher test).

In summary, the nonpregnant group (Group P) demon-
strated an aversion to placenta when tested at the gesta-
tional interval (30 days), but not after 44 days. Eemalesin
the pregnant group (Group P) did not show an aversion to
their own placenta during parturition, but they refused to
eat donor placenta presented just after parturition. As in
the nonpregnant group, most of the pregnant females ate
donor placenta after 44 days. Although the 2 groups did
demonstrate an aversion to placenta at different times, the
groups were not significantly different from each other
during any of the tests.

EXPERIMENT 3

Experiment 3 was designed to examine the effects of
TAC induced during the first parturition on the incidence
of placentophagia at the second parturition. Females in
Experiment 3 received conditioning immediately after the
completion of parturition, whereas females in Experiments
1 and 2 had been conditioned during the nonpregnant,
cycling state.

<<   <   2   3   4   5   6   7   8   >   >>