SUPEROVULATION IN MERINO EWES WITH A SINGLE FSH-P APPLICATION VS MULTIPLE INJECTIONS

79 estrous synchronized sheep (Merinoland) were superovulated with FSH-P (total dosis 25 mg or 17 mg). Group 1 got multiple FSH-P injections i.m. in 12 h intervals (group 1/25 mg and group 1/17 mg), while in groups 2 and 3 the total dosis was given subcutaneously 36 h before gestagen withdrawal (group 2/25 mg and group 2/35 mg) or at the end of synchronisation (group 3/35 mg and group 3/17 mg). After intrauterine insemination embryo collection was performed on day 7-11 (day of estrous = d0). In the different stimulation groups the number of ovulations was 11,8 +/- 4,6; 9,2 +/- 5,5; 8,4 +/- 6,4; 7,2 +/- 7,2; 8,8 +/- 6,5 and 4,2 +/- 2,9, respectively. The reaction between group 3/17 mg and groups 1/25 mg (p < 0,001), 1/17 mg (p < 0,01), 2/25 mg (p < 0,05) and 3/25 mg (p < 0,05) differed significantly. The number of ovulations as well as the number of number of embryos and oocytes recovered in the different experimental groups indicate that a single FSH application, especially given in a higher dosis and at the end of estrus synchronisation is a reasonable alternative for the superovulation regimen used normally in sheep.