University of Western São Paulo, (UNOESTE), Presidente Prudente, São Paulo, Brazil.
Veterinarian Haras, Avaré, São Paulo, Brazil.
J Equine Vet Sci. 2021 Feb;97:103325. doi: 10.1016/j.jevs.2020.103325. Epub 2020 Nov 21.
The objective of this study was to quantify serum progesterone levels, uterine features, and pregnancy rates in acyclic, embryo recipient mares using a bovine progesterone-releasing intravaginal device in a commercial embryo transfer (ET) program. The study included 73 recipient mares of unknown breed, aged 3-10 years, weighing 350-500 kg, and kept under an intensive management system on Tifton 85 (Cynodon spp.) pastures with water and mineral salt ad libitum. The horses were divided into two groups: a group with a progesterone-releasing intravaginal device (1 g progesterone, G-IVP4, n = 24) and a control group (G-iP4, n = 49) receiving an injection of 1,500 mg long-acting progesterone. Jugular blood was collected for the G-IVP4 group for subsequent progesterone measurement by radioimmunoassay on three occasions: Day 0 (D0), intravaginal device was placed; Day 5 (D5), day of the ET; and Day 9 (D9), day of pregnancy diagnosis. There was an increase (P < .0001) in serum progesterone levels on D5 and D9 compared with D0 (4.09 ± 0.81 and 6.45 ± 1.03 ng/mL vs. 0.71 ± 0.14 ng/mL). There were no differences among groups in the pregnancy rate (P > .05), with rates of 83.33% and 73.46% for G-IVP4 and G-iP4, respectively. In conclusion, the intravaginal route for absorption of 1 g of progesterone device increased the serum level of progesterone sufficiently to prepare the uterus of acyclic recipient mares for ET, and the conception rate was similar to the standard protocol using long-acting injectable progesterone.
本研究的目的是通过在商业胚胎移植（ET）计划中使用牛孕激素释放阴道装置，量化非周期性胚胎受体母马的血清孕激素水平、子宫特征和妊娠率。该研究包括 73 匹未知品种的受体母马，年龄 3-10 岁，体重 350-500 公斤，在蒂夫顿 85（Cynodon spp.）牧场上进行集约化管理，可自由饮水和摄入矿物质盐。这些马被分为两组：一组使用孕激素释放阴道装置（1 克孕激素，G-IVP4，n=24），另一组接受 1500 毫克长效孕激素注射（G-iP4，n=49）。G-IVP4 组采集颈静脉血，随后通过放射免疫分析法测量孕激素，共进行三次测量：第 0 天（D0），放置阴道装置；第 5 天（D5），ET 日；第 9 天（D9），妊娠诊断日。与 D0 相比，D5 和 D9 时血清孕激素水平升高（P<.0001）（4.09±0.81 和 6.45±1.03 ng/mL 比 0.71±0.14 ng/mL）。两组间妊娠率无差异（P>.05），G-IVP4 和 G-iP4 组的妊娠率分别为 83.33%和 73.46%。总之，阴道途径吸收 1 克孕激素装置足以提高非周期性受体母马的血清孕激素水平，为 ET 做好准备，并且妊娠率与使用长效注射孕激素的标准方案相似。
