INFLUENCE OF PMSG AND PMSG HCG-COMBINATIO NS ON FERTILITY OF WEANED SOWS .1. EFFECT OF DIFFERENT METHODS OF CYCLE STIMULATION ON THE CONCENTRATIONS OF THE SEX-HORMONES LH, 17-BETA-ESTRADIOL, FSH AND PROGESTERONE IN PRIMIPAROUS SOWS/

At this time different hormone preparations and biotechnological metho ds for cycle stimulation are in use. A cycle stimulation only by PMSG or by a PMSG/hCG-combination 24 h after weaning is common. In this inv estigation both methods should be compared in primiparous sows after a 4-week suckling period considering hormone patterns. There were 16 pr imiparous sows for the investigation. The hormones FSK, 17 beta-estrad iol, LH and progesterone in blood plasma were analysed and the start a nd the period of standing heat were recorded. In sows stimulated only by PMSG the start of standing heat was more uniforme and the period we re longer as in non-stimulated or by PMSG/hCG-combination stimulated s ows. Also their patterns of hormones were more clear and uniform. In t he investigation on hand the method of cycle stimulation by 1000 i.u. PMSG 24 h after weaning with stimulation of ovulation 80 h after weani ng by 500 i.u. hCG proved to be the: best-suited one to the endogenous hormone-patterns of primiparous sows after a 4-week suckling period.