Effect of delayed sponge withdrawal on the superovulatory response to pregnant mare serum gonadotrophin and on embryo recovery in sheep

Abstract

Forty-five ewes (29 Romanov X Dorper, 9 Karakul, and 7 Dorper) were divided into four groups, synchronized using progestagen sponges and superovulated with 1000 IU pregnant mare serum gonadotrophin. Sponges were withdrawn on days 13, 14, 15 and 16 (in groups 1-4, respectively) after sponge insertion (day 0). Fixed-time cervical as well as laparoscopic AI was performed. The fallopian tubes and uterus were flushed eight days after sponge withdrawal. Total ovarian response (follicles > 8 mm and corpora lutea), total corpora lutea, total embryo and ova recovery, total transferable embryos and left and right ovarian reactions (follicles > 8 mm and corpora lutea; corpora lutea; embryo and ova recovery; transferable embryos for each ovary) were noted per ewe in each group. No significant differences were observed between the four groups in all parameters measured. When data were pooled, the total ovarian response was 416, number of corpora lutea was 274, the number of ova and embryos recovered was 141 (recovery rate 51.5%) and the number of transferable embryos was 102. No significant differences between left and right ovarian reactions were detected within and between groups.

Vyf-en-veertig ooie (29 Romanov X Dorper, 9 Karakoel en 7 Dorper) is in vier groepe verdeel, gesinchroniseer met progesteroonsponse en gesuperovuleer met 1000 IE dragtige merrieserumgonadotrofien. Sponse is onttrek op dae 13, 14, 15 en 16 (in groepe 1-4, respektiewelik) na sponsing (dag 0). Die ooie is op vasgestelde tye servikaal en laparoskopies geïnsemineer. Die fallopiese buise en baarmoeder is agt dae na sponsonttrekking gespoel. Die totale ovariumrespons (follikels > 8 mm en corpora lutea), totale corpora lutea, totale embrio- en ova-herwinning, totale oorplaasbare embrio's en linker- en regterovariumreaksies (follikels >8 mm en corpora lutea; corpora lutea; embrio- en ovaherwinning; oorplaasbare embrio's vir elke ovarium) is bepaal per ooi vir elke groep. Geen betekenisvolle verskille tussen die vier groepe is opgemerk vir die parameters wat gemeet is nie. Wanneer waardes gepoel is, was die totale ovariumrespons, 416; die aantal corpora lutea, 274; die aantal ova en embrio's herwin, 141 (herwinningspersentasie 51.5%); en die aantal oorplaasbare embrio's, 102. Geen betekenisvolle verskille tussen linker- en regterovariumreaksies binne en tussen groepe is opgemerk nie.

Keywords: Embryo, PMSG, sheep, superovulation