[The course of ovulation after biotechnical puberty induction in young sows]

Four experimental series were applied to 342 prepuberal young sows to establish ovulation developments. Different periods of time were allowed to elapse between injection and slaughter. Injected were 400 IU PMS/200 IU HCG or 500 IU PMS/250 IU HCG. Onsets of ovulation were found to be highly differentiated and variable. Some of the animals had completed ovulation 72 hours after application of gonadotrophin, whereas in others had not even started 168 hours after such application. In the majority of all sows involved in the experiments ovulation occurred 96--144 hours from application of the gonadotrophis hormone. In other words, fertile semen should be present in the genital tract of sows in that period of time, if the concept of deadlineoriented insemination is followed.