Fig. 3
The short-term effect of an intrauterine device (IUD) inserted on day 0 (A,B, C) and IUD inserted on days 5–6 post-ovulation (D, E, F) on concentrations of progesterone (P4) (A, D), prostaglandin E2 (B, E), and 13,14-dihydro-15-keto PGF2α (C, F) in the blood plasma of mares. Asterisks indicate significant differences (*P < 0.05) between IUD mares and control mares (without IUD) at the same time point (hour). Arrow indicates time point of IUD insertion