ILXPERIMENTAL PROCEDURE AND RESULTS.

Experiment TI:

In 1965 17 sows and 19 gilts (Dutch Landrace) were
medicated with 1 mg I.C.I.-compound 33.828 per kg
bodyweight. The gilts were fed in groups of three
or four; some of the sows were fed individually,
oithersitinygroups i ofiltwolper pen,. This has idits
influence on the variation in compound intake.

Group I.

7 Sows, who had shown one heat period after weaning
of the piglets, were medicated for 20 days. The
resulting synchronisation was unsatisfactory.

Group II.
10 Lactating sows were medicated for 10 days, 4
days before - and 6 days after weaning of the
piglets. The synchronisation of oestrus was
un'sucecesstuls

In this group the influence of the I.C.I.-
compound on the milk ejection was studied also. The time
during which the piglets were suckling after 2
hours fastening was used as a measure of milk
ejection. Weighing the sow and/or the piglets
before and after suckling did not prove to: be
sufficiently accurate. The average time of milk
let down of 7 lactating sows was as follows:
223122£§5E 1st day 2nd day 3rd day U4th day
38 sec. DS EC s 25 sec. 21 sec. 15 sec.
The differencesbetween the first two days and
the last two days being significant (P <0.01).

Eronpadidd,

The 19 gilts had shown at least one heat period

before medication started and were divided into

three subgroups and were all treated as the sows

of group I.

a. 7 gilts showed a well synchronised oestrus and
were allowed to deliver their piglets.

b. 6 gilts should be slaughtered three days after

the synchronised heat, however, four of them

never came into heat after medication.

6 gilts were slaughtered five days after termination

of the medication; the ovaria of all gilts showed

large follicles, approaching the ovulation stage.

lo