Vle CONG. INTERN. REPROD. ANIM. INSEM. ARTIF., PARIS, 1968, VOL. II

Because all treated animals experienced intensive and
abnormally long heat symptoms, the pregnancy rate, on-—
ly 39 %, indicates a dose level too high to establish
a normal response.

Second experiment: Therefore, 38 sows received at
weaning only 1 ml of “I? All animals demonstrated nor-
mal heat on day 3 to % and 68.4 % conceived at this

estrus (against 70.4 % of 17 controls). Litter size:
8.92 in treated and 10.26 in control animals.

Third experiment: 26 sows were treated at weaning
with 1 ml of "II". Normal heat symptoms were shown by
3.8 % on day 2, by 77.0 % on days 3 and 4,~ and by 192
% later. 77.0 % conceived at the first heat.

Of the 14 sows which had litters to date, 2 had
4-8, 8 had 9-12, 3 had 13-15 and 1 had 16 piglets.

D) Improvement of synchronization after treatment with
AIMAX by androgen-estrogens:

22 gilts received AIMAX (100 mg daily) for 20 days;
a) 13 gilts were treated with 0.5 ml of "I’
b) 9 gilts with 1.0 ml of "I’in addition on day 21

All animals from a) displayed heat 2 to 4 days la-
ter; animals from b) showed heat on day 2 to 5.
Conception rate after first service: a) 38.5 %;

b) 44.4 %.

Summarlz

The results obtained from these preliminary obser-
vations with androgen-estrogen combinations show:

1) An induction of a well synchronized heat res-—
ponse has been obtained in anestrous sows and gilts
as well as in sows and gilts after weaning by a single
injection.

2) The interval between weaning and first heat has
been significantly shortened.

SROnA negative influence on litter size has been ob-

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