Graf Lehndorff Institute for Equine Science, Brandenburg State Stud, Neustadt (Dosse), Germany.
Theriogenology. 2011 Feb;75(3):421-8. doi: 10.1016/j.theriogenology.2010.05.009. Epub 2010 Dec 7.
The treatment of early pregnant mares with a history of repeated early embryonic loss with the progestin altrenogest has become routine; however no controlled studies on the efficiency of altrenogest to prevent embryonic losses are available so far. In the present study, we have investigated effects of altrenogest treatment in mares on conceptus development and the secretion of LH, progesterone, and eCG until day 100 of pregnancy. In addition, differences related to age of mares were assessed. Mares were treated with altrenogest (0.044 mg/kg per os once daily) or sunflower oil (10 ml per os once daily) from day 6 to day 100 after ovulation. Blood samples for analysis of LH, progesterone, and eCG were collected. The size of the embryonic vesicle and embryo/fetus was determined by ultrasound. No difference in the per cycle pregnancy rate between altrenogest-treated (75%) and sunflower oil-treated mares (74%) was detected (n.s.). A significant effect of age but not of altrenogest treatment on mean diameter of the embryonic vesicle was found between days 12 and 22 of pregnancy (e.g. day 15: control, 4-8 years: 22.9 ± 1.0 mm, >8 years: 22.0 ± 1.7 mm, altrenogest, 4-8 years: 26.1 ± 2.0 mm, >8 years: 20.4 ± 1.0 mm, P < 0.05). A significant effect of age and treatment on size of the embryo proper between days 30 and 45 was detected (P < 0.05). In the control group but not in the altrenogest group, size of the embryo proper respective fetus was negatively correlated with age of the mares (day 30: r = -0.834, P < 0.05; day 35: r = -0.506, P < 0.05). Plasma concentrations of LH and progesterone were neither effected by age nor by treatment of mares, but significant effects of age and altrenogest treatment on eCG concentrations between days 40 and 130 were detected (P < 0.05). The present study demonstrates for the first time a positive influence of altrenogest-treatment on a retarded development of the embryo respective fetus around the beginning of placentation in mares older than 8 years.
对有早期胚胎丢失史的早期妊娠母马使用孕激素烯丙孕素进行治疗已成为常规；然而，迄今为止，尚无关于烯丙孕素预防胚胎丢失效率的对照研究。在本研究中，我们研究了烯丙孕素处理对妊娠第 100 天的胚胎发育和 LH、孕酮和 eCG 分泌的影响。此外，还评估了与母马年龄相关的差异。母马从排卵后第 6 天到第 100 天每天口服 0.044 mg/kg 的烯丙孕素或葵花籽油（10 ml）。收集分析 LH、孕酮和 eCG 的血样。通过超声检查确定胚胎泡和胚胎/胎儿的大小。烯丙孕素处理（75%）和葵花籽油处理（74%）的母马每周期妊娠率无差异（n.s.）。妊娠第 12 至 22 天，胚胎泡的平均直径存在年龄的显著影响，但烯丙孕素处理无影响（例如，第 15 天：对照组，4-8 岁：22.9 ± 1.0mm，>8 岁：22.0 ± 1.7mm，烯丙孕素，4-8 岁：26.1 ± 2.0mm，>8 岁：20.4 ± 1.0mm，P < 0.05）。妊娠第 30 至 45 天，胚胎大小的显著影响与年龄和处理相关（P < 0.05）。在对照组中，但在烯丙孕素组中，胚胎和胎儿的大小与母马的年龄呈负相关（第 30 天：r = -0.834，P < 0.05；第 35 天：r = -0.506，P < 0.05）。LH 和孕酮的血浆浓度不受年龄或母马处理的影响，但在妊娠第 40 至 130 天，检测到 eCG 浓度存在年龄和烯丙孕素处理的显著影响（P < 0.05）。本研究首次证明，烯丙孕素处理对 8 岁以上母马的胎盘形成早期胚胎和胎儿的发育迟缓有积极影响。
