Effect of the administration of alfaprostol 3 or 6 days after ovulation in jennies: ultrasonographic characteristic of corpora lutea and serum progesterone concentration

Donkey jenny's corpus luteum (CL) response to PGF2α analogues has not been investigated in depth. Aim of this study was to evaluate the donkey jenny's corpus luteum (CL) ultrasonographic characteristics (diameter, area and vascularized area) by B-Mode, Color Doppler and serum progesterone concentration ([P4]) after treatment with the prostaglandins F2α analogue alfaprostol at day 3 or day 6 after ovulation (groups PG3 and PG6, respectively). [P4] was positively correlated (P < 0.0001) with CL diameter: r2 = 0.17; area: r2 = 0.21 and vascularized area: r2 = 0.54. The interovulatory interval was significantly reduced in the PG6 group (15 ± 1.8 days), compared to the control group (24.5 ± 2.9 days; P < 0,05), while there were no significant differences in interovulatory interval between PG3 (21.7 ± 7.9 days) and control or PG6 group. [P4], in the 6 jennies of the PG6 group, dropped under 1 ng/mL within 2 days after treatment, remaining under this concentration until [P4] raised again to levels comparable with those of the control group until spontaneous luteolysis. After alfaprostol administration, one of the 2 remaining PG3 group jennies showed a complete luteolysis, and the other one underwent a partial luteolysis and ovulated in diestrus.