[Trials to induce ovulation with Berlin-Chemie Gn-RH vet. in prepuberal gilts]

Combinations of pregnant mare serum gonadotrophin (PMSG) with Gn-RH were tested for ovulation-triggering action on 93 prepuberal gilts, aged between 185 and 210 days. The action of PMSG was somewhat inhibited by Gn-RH, when 500 IU of PMSG were given together with 600 micrograms or 900 micrograms of Gn-RH. An infection of 900 micrograms Gn-RH, applied three days from PMSG administration, caused ovulations in 83 per cent of the animals up to the fifth day from PMSG administration on which laparotomy was performed. Smaller intervals of one or two days caused the same effect on 25 or eight per cent of the animals. The presence of a sufficiently high number of graafian follicles suggested pronounced overreaction to all variants of treatment, using PMSG alone or in combination with Gn-RH. The effect of lower Gn-RH doses seems worthwhile another study.