Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana (IL); Department of Veterinary Medical Sciences, University of Bologna, Ozzano dell'Emilia (BO), Italy.
Department of Veterinary Clinical Medicine, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, Urbana (IL).
J Equine Vet Sci. 2022 Nov;118:104075. doi: 10.1016/j.jevs.2022.104075. Epub 2022 Jul 10.
Progesterone is pivotal to maintain pregnancy in the first trimester and low concentration (<4 ng/mL) has been associated with early pregnancy loss. Measurement of progesterone is widely used in practice to determine whether a mare needs progestin supplementation. Therefore, the objective of the present study was to determine progesterone concentration and the luteal tissue area in mares non-bred, and those bred becoming pregnant, and those failing to become pregnant. We hypothesized that pregnant mares have greater progesterone concentration than non-pregnant mares. Fifty-two cycles of mares (n = 14) were monitored by ultrasonography every other day until detection of a pre-ovulatory follicle. Then deslorelin acetate was administered to induce ovulation. Twenty-four hours later, mares were bred (∼2 billion progressively motile sperm extended in 50 mL; n = 37 cycles) or a sham-bred (50 mL of extender; n = 15 cycles). Ovulation was confirmed and number of corpora lutea and the luteal tissue area were recorded daily until 10-days post-ovulation. Progesterone concentration was assessed daily from the day of the ovulation up to 10-days post-ovulation. Pregnancy diagnosis was carried out at 10- and 13-days post-ovulation. Of the bred mares, 20 of them became pregnant and 17 did not. Data were analyzed with a mixed model, Tukey's test as post-hoc, and Pearson's coefficient of correlation. Progesterone concentration and luteal tissue area varied with time (P = .001) but not with group (P > .05). Multiple ovulations were associated with greater progesterone concentration and luteal tissue area (P = .0001). There was a moderate positive association between the number of ovulations and luteal tissue area (r = 0.54; P = .0001). The lack of change in the progesterone concentration and luteal tissue area between bred and non-bred mares suggests that horse seminal plasma does not affect luteal function in mares. As all mares had progesterone above 4 ng/mL after 5-days post-ovulation; it is possible that if mares with abnormal progesterone concentration were used, the results could have been different. In conclusion, pregnancy was not associated with greater progesterone concentration or luteal tissue area.
孕酮对于维持妊娠的头三个月至关重要，低浓度（<4ng/mL）与早期妊娠丢失有关。在实践中，孕酮的测量广泛用于确定母马是否需要孕激素补充。因此，本研究的目的是确定未配种母马、配种怀孕母马和未怀孕母马的孕酮浓度和黄体组织面积。我们假设怀孕母马的孕酮浓度高于未怀孕母马。52 个母马周期（n=14）每隔一天通过超声监测，直到检测到排卵前卵泡。然后给予去势促性腺激素释放激素乙酸酯诱导排卵。24 小时后，母马配种（约 20 亿个具有渐进运动能力的精子在 50mL 中延伸；n=37 个周期）或假配种（50mL 稀释液；n=15 个周期）。排卵后每天记录排卵后黄体数量和黄体组织面积，直到排卵后 10 天。从排卵日起每天评估孕酮浓度，直到排卵后 10 天。排卵后 10 天和 13 天进行妊娠诊断。配种的母马中，20 匹怀孕，17 匹未怀孕。数据采用混合模型进行分析，Tukey 检验作为事后检验，以及 Pearson 相关系数。孕酮浓度和黄体组织面积随时间变化（P=0.001），但不受组别的影响（P>0.05）。多排卵与更高的孕酮浓度和黄体组织面积相关（P=0.0001）。排卵次数与黄体组织面积之间存在中度正相关（r=0.54；P=0.0001）。配种和未配种母马之间孕酮浓度和黄体组织面积没有变化表明，马精液不会影响母马的黄体功能。由于所有母马在排卵后 5 天孕酮浓度均高于 4ng/mL；如果使用孕酮浓度异常的母马，结果可能会有所不同。总之，妊娠与更高的孕酮浓度或黄体组织面积无关。
