Department of Animal and Veterinary Sciences, Clemson University, Clemson, SC 29634, USA.
J Anim Sci. 2012 Nov;90(11):3770-7. doi: 10.2527/jas.2011-4713. Epub 2012 Jun 4.
The advent of embryo transfer has allowed horses to continue to train and compete during the breeding season. However, the associated stress of exercise may be detrimental to reproduction. The objectives of this study were to evaluate differing exercise protocols on reproductive blood flow and embryonic outcomes in mares. Light-horse mares were randomized into control (n = 4), partial-exercised (n = 6), and full-exercised (n = 6) groups. Partial-exercised mares were moderately exercised 30 min daily during the periovulatory period and rested after ovulation for 7 d. Full-exercised mares were exercised for 30 min daily throughout the reproductive cycle. Mares were artificially inseminated during estrus and subjected to uterine flush for embryo recovery on d 7 post ovulation. Blood flow through both ovarian arteries and vascular perfusion of the wall of the preovulatory follicle were examined by color Doppler ultrasonography. Results indicated exercise induced greater serum cortisol concentrations (P < 0.05). Embryo recovery rates were reduced in exercised (20/46, 43%) compared with control (14/21, 67%) mares (P < 0.10). When examined separately, embryo recovery rates for partial-exercised (11/25, 44%) and full-exercised (9/21, 43%) mares were not significantly different. Additionally, fewer quality Grade 1 embryos were recovered from partial-exercised mares compared with both control and full-exercised mares (P < 0.05). Blood flow through both ovarian arteries was greater in both exercised groups in the days leading up to ovulation (P < 0.05). However, vascular perfusion of the wall of the preovulatory follicle on the day before ovulation was less in both partial-exercised (45.9 ± 3.0%) and full-exercised (44.8 ± 3.4%) mares vs. control (54.9 ± 3.6%; P < 0.05). In exercised mares, vascular perfusion of the follicle wall was greater when an embryo was recovered (P < 0.01). No differences were found in follicle ovulatory diameter among exercised and non-exercised mares. When groups were combined, follicle diameter was greater when an embryo was recovered (44.9 ± 1.0 mm) compared with an unsuccessful embryo recovery attempt (42.8 ± 0.7 mm; P < 0.05). In conclusion, these data demonstrated that exercise increased ovarian arterial blood flow leading up to ovulation and decreased vascular perfusion of the wall of the preovulatory follicle. Mares given rest the day after ovulation up until an embryo collection attempt did not improve embryo recovery rates.
胚胎移植的出现使得马在繁殖季节也能继续训练和比赛。然而，运动带来的相关压力可能会对繁殖产生不利影响。本研究的目的是评估不同的运动方案对母马生殖血流和胚胎结果的影响。轻型马被随机分为对照组（n = 4）、部分运动组（n = 6）和完全运动组（n = 6）。部分运动组的母马在排卵期间每天适度运动 30 分钟，并在排卵后休息 7 天。完全运动组的母马在整个生殖周期中每天运动 30 分钟。母马在发情期接受人工授精，并在排卵后第 7 天进行子宫冲洗以回收胚胎。通过彩色多普勒超声检查评估两个卵巢动脉的血流和排卵前卵泡壁的血管灌注。结果表明，运动导致血清皮质醇浓度升高（P < 0.05）。与对照组（14/21，67%）相比，运动组（20/46，43%）的胚胎回收率降低（P < 0.10）。当分别检查时，部分运动组（11/25，44%）和完全运动组（9/21，43%）的胚胎回收率没有显著差异。此外，与对照组和完全运动组相比，部分运动组回收的优质 1 级胚胎数量较少（P < 0.05）。在排卵前几天，两个运动组的两个卵巢动脉的血流都增加（P < 0.05）。然而，在排卵前一天，部分运动组（45.9 ± 3.0%）和完全运动组（44.8 ± 3.4%）的排卵前卵泡壁的血管灌注均低于对照组（54.9 ± 3.6%；P < 0.05）。在运动的母马中，当回收胚胎时，卵泡壁的血管灌注增加（P < 0.01）。运动和非运动母马的卵泡排卵直径没有差异。当将两组合并时，当回收胚胎时，卵泡直径较大（44.9 ± 1.0 毫米），而胚胎回收尝试失败时，卵泡直径较小（42.8 ± 0.7 毫米；P < 0.05）。总之，这些数据表明，运动增加了排卵前的卵巢动脉血流，并减少了排卵前卵泡壁的血管灌注。在排卵后直到进行胚胎采集尝试的那天给母马休息并没有提高胚胎回收率。
