RESULTS

E1) The suppression of oestrus was good. Only 2 gilts came in
oestrus during the treatment and this was 3 days after beginning
of the administration.

(2) The synchronisation of the oestrus after treatment in this
field trial is demonstrated in table 1.

The result of all gilts taken together may be called moderats.
The gilts which were in heat already prior to the treatment
(Group B+) show very good results (83% on days 4 up to and
including 8).

On further study it appeared that the average age of the gilts
in Group B- was about 3 months younger than of those in Group B+.
From this it appears that in fact synchronisation may not take
place until the gilts are sexually mature, and not prior to that
time, which is obvious. Moreover it may be noticed that the last
gilt (in oestrus after 92 days) was an abnormal case because of
illness, of which no further data are knouwn.

We may draw the conclusion that oestrus synchronisation by means
of "Aimax" is correct, provided it is used in sexually mature
animals.

(3) The "quality" of the oestrus judged on standing-reflex,
saecretion from the vulva, swelling and colour of the vulva,
showed no differences between the treated and control groups.
The difference in duration of the oestrus, stated in table 2,
seems of no importancs.

(4) The data regarding reproduction are given in Table 2.

The fertility in treated- and control-groups is the same when
considering the percentage of pregnancy after the first
insemination and moreover considering the number of the non-
pregnant animals.

The litter-size in the treated group is 9.0 piglets and in the
controls 8.6, This difference may well be by coincidence, but in
any case it is in favour the treated groups.

DISCUSSION

Not a single pig breeder did observe anything about the some-
times reported complaint about reduced food intake when using
"Aimax". They were very satisfied about conception rate. In this
respect it may be said that all farmers were skilled and
interested pig breeders. From the results of this field trial
we may draw the conclusion that good synchronisation of the
oestrus may be obtained in sexually mature gilts, and that the
reproduction in gilts pregnant after administration of "Aimax"
is undisturbed and normal.

For a better and easier determination of the oestrus in gilts
the administration of "Aimax" may be useful, because the number
of checking days are restricted.

x At the time "Aimax" still had the code of ICI 33.828. The
necessary "Aimax™ has been made available by ICI (HOLLAND). We
express our thanks for this and for the further assistancs.

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