The effect of oxytocin and PGF2α on the uterine involution and pregnancy rates in postpartum Arabian mares

In this study, the effects of oxytocin and an analog of prostaglandin (cloprostenol) on the uterine involution and pregnancy rates were investigated. Mares received 3 ml of 0.9% NaCl in Group C (n = 10), 30 IU/mare of oxytocin in Group O (n = 10) and 250 μg/mare of cloprostenol in Group P (n = 10) within 12 h after parturition. The gravid uterine horn's cross-sectional diameter was measured by ultrasonography. The mean uterine diameters did not differ significantly between the treatment (O and P) and the control (C) groups (p > 0.05). The difference between the postpartum ovulation periods (Group C: 12.6 ± 0.72 days, Group O: 15 ± 1.33 days, Group P: 14.6 ± 1.11 days), the pregnancy rates at foal heat (Group C: 60%, Group O: 60%, Group P: 80%) and the embryonic death rates at foal heat (Group C: 33.3%, Group O: 16%, Group P: 25%) were not found to be statistically significant between the treatment and the control groups. The mean progesterone concentrations were similiar in all groups and decreased continuously from parturition to until foal heat (Group C: from 2.43 ± 0.24 to 0.66 ng/ml, Group O: from 3.07 ± 0.6 to 0.27 ± 0.27 ng/ml and Group P: from 2.8 ± 0.44 to 0 ng/ml) (p > 0.05). In conclusion, it was decided that the oxytocin and PGF2α treatments performed on the mares with the purpose of stimulating involution had no effect on the duration of parturition–first ovulation, the shrinkage of the uterus diameter, the pregnancy and embryonic death rates.