The name is absent

ENGWΛLL AND KRISTAL

METHOD

Animals

Subjects were 25 virgin female rats that had exhibited
Placentophagia during the pretest.

Procedure

Mating and procedure at the first parturition. Females
were assigned to 1 of 2 groups, Group L (LiCl treatment),
or Group SP (Saline control-pregnant). Both groups were
mated within 1 week after completion of the pretest.
Breeding procedures were as in Experiment 1.

Females were moved to test cages on the afternoon prior
to the date of expected parturition. When the female began
to deliver, food and water were removed from the cage. As
the females delivered each placenta, the placenta was
grasped with a pair of large forceps and removed from the
cage. If the pup was detached from the placenta before the
delivery of the placenta, the placenta alone was collected. If
the pup and the placenta were delivered as an intact unit,
both were removed from the cage. The pup was returned
after the placenta had been detached from the pup by the
experimenter.

The collected term placentas were immediately placed in
a 23 ml glass vial which contained a few drops of saline, and
were maintained at O^oC in an ice water bath throughout the
Parturitional sequence. Thirty min after the delivery of the
last pup, 4 placentas were removed from the collection vial
and warmed to about 37°C. The remaining placentas were
transferred to 6 ml vials and frozen with a few drops of
saline for further use.

The litter was removed from the puerpera’s cage and
placed under a 75 W, white incandescent bulb. The warmed
placentas were transferred to a specimen dish and placed in
the female’s cage. As soon as the female consumed all the
presented placentas, females in Group L were injected with
a 0.15 M LiCI solution (20 ml∕kg body weight, IP). Females
of the Group SP were injected with a comparable volume of
isotonic saline. All injections were completed within 15 min
after the consumption of the placenta. Females (but not
the litters) were returned to their home cages. Food and
water were removed for 2 hr following the injection of LiCI
or saline.

Mating and observations at the second parturition.
Group L was divided into 2 subgroups, Subgroup LP
(pregnant) and Subgroup LP (not pregnant). Because of the
difficulties entailed in collecting placenta from parturient
females, it was impossible to completely eliminate ρlacento-
phagia during parturition in every female. Females were
assigned to the 2 subgroups (n = 9 for each) on the basis of
the number of placentas eaten during the first parturition;
both subgroups contained females that had consumed small
(≤2) and large (>2) numbers of placentas during parturi-
tion. The mean number of placentas consumed during the
first parturition for Subgroups LPand LPwere 2.1 1 ± 0.68
and 3.33 ± 0.90, respectively. The mean number of
placentas consumed by the saline control group, Group SP,
was 4.17 і 0.79. A one-way ANOVA revealed that these
group values were not significantly different, ∕∙'(2,2l) =
1.54,p>O.IO.

Females of Subgroup LP and Group SP were allowed 1
week after parturition before the vaginal smear procedure
was begun. Females of the 2 pregnant groups were then
mated using procedures described in Experiment 1.

Thirty min after the delivery of the last pup, females in
Group SP and Subgroup LP were presented with 4 term
placentas in a specimen dish. The term placenta was that
which had been collected during the first parturition.
Otherwise, the procedures for parturitional observations
were identical to those used in Experiment I.

Observations of maternal behavior and 2 week post-
partum test. Both procedures were conducted as in Experi-
ment I except that term placenta, rather than surgically
obtained donor placenta, was used.

Testing procedures for nonpregnant females. Females in
Subgroup LP were given a single exposure to term placenta
38 days after parturition. The first control interval approxi-
mated the interval between the first and second parturitions
of females in Subgroup LP.

Term placenta was also used for test after the second
control interval; this test was administered to Subgroup LP
52 days after the first parturition.

RESULTS

Observations at the First Parturition

The term placenta presented immediately after the first
parturition was completely consumed by all females in the
2 groups given TAG (Subgroups LP and LP). In the group
that was to receive a saline injection (Group SP), 1 female
failed to consume the presented term placenta; after
elimination of this animal from the experiment. Group SP
contained 6 animals.

TABLE 3

DESIGN AND RESULTS OF EXPERIMENT 3: TAC TO PLACENTA
INDUCED AT FIRST PARTURITION (PROPORTION OF GROUP
exhibiting pi.AcentophagiAi

*AII animals determined to be placentophages in a pretest.
+Only I pairing was given in all cases.

Observations of Placentophagia at the Second Parturition

Five of the 9 animals in Subgroup LP (pregnant, LiCl
treated) showed a decrement in the consumption of their
own placenta during parturition (placentophagia scores
ranged from 0.77 to 0.13 with a mean of 0.37 ± 0.12).
Although all 9 females in Subgroup LP continued to
consume at least some of their own placenta during
parturition, only 1 of the females (an eater during
parturition) ate donor term placenta offered just after
parturition. In summary, females in the pregnant, LiCI-
treated group continued to consume about 1/3 of their own
placentas during parturition and were not likely to consume
donor term placenta presented after parturition.

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