[Studies on the success of insemination after various insemination dates in biotechnical puberty induction of young sows].

Different frequencies and periods of insemination were checked with the view to optimising puberty induction to young sows, for which purpose 500 IU PMS/250 IU HCG were injected to 571 animals in seven experiments. Insemination was carried out by deadline, since follicle stimulation was exhibited by almost all animals following the above treatment, while only some of them displayed tolerance. Advantage was taken of the induced oestrus, since its ovulation rates were higher than those associated with subsequent heat cycles, and because a synchronised second oestrus was recordable only from some of those animals which exhibited follicle stimulation in response to puberty induction. The most favourable results in terms of pregnancy and number of embryoes, against the background of the great variability in ovulation onset, were obtained, if insemination was applied 72, 96, and 120 hours after gonadotrophin treatment. From among the variants with two inseminations, good results were obtained from those 96 and 120 hours after PMS/HCG treatment.