Department of Animal Reproduction, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, SP, Brazil.
North Florida Research and Education Center, Institute of Food and Agricultural Sciences, University of Florida, 3925 Hwy 75, Marianna, FL, 32446, USA.
Trop Anim Health Prod. 2024 Feb 13;56(2):76. doi: 10.1007/s11250-024-03913-3.
Three experiments were conducted to evaluate the effects of long-acting injectable progesterone (iP4) in buffalo cows. In Experiment 1, ovariectomized buffaloes received 300 mg (iP300) or 600 mg (iP600) of iP4, and serum P4 concentrations were evaluated. In experiment 2, three groups were compared: control or administration of 300 mg of iP4 3 (iP4-D3) or 6 days (iP4-D6) after timed artificial insemination (TAI). On day 16, reproductive tract was recovered for conceptus, endometrium, and corpus luteum (CL) analysis. In experiment 3, pregnancy per AI (P/TAI) and proportion of pregnancy losses were evaluated after administration of 300 mg of iP4 3 (iP4-D3) or 6 days (iP4-D6) after TAI in lactating buffaloes. In experiment 1, serum P4 concentrations remained over 1 ng/mL for ~ 3 days in both groups. The 300 mg dose was used in subsequent experiments. In experiment 2, CL weight and endometrial glands density were decreased, and conceptus length was increased in iP4-D3 compared to control and to iP4-D6 (P < 0.05). Transcript abundance of Prostaglandin F Receptor (FP) and ISG15 in CL and of ISG15 and MX1 in endometrium was greater in iP4-D3 when compared to control and to iP4-D6 (P < 0.05). In experiment 3, there was no difference among experimental groups for P/TAI at D30 and pregnancy losses (P > 0.1); however, iP4-D3 presented a lower P/TAI at day 60 (41.7%) when compared to control (56.8%) and iP4-D6 (57.7%; P = 0.07). In conclusion, administration iP4 at 3 days after TAI affects CL development and consequently decreases final pregnancy outcome in buffaloes.
进行了三项实验来评估长效注射用孕酮（iP4）在水牛中的作用。在实验 1 中，去卵巢水牛接受 300mg（iP300）或 600mg（iP600）的 iP4，并评估血清 P4 浓度。在实验 2 中，比较了三组：对照组或在定时人工授精（TAI）后 3 天（iP4-D3）或 6 天（iP4-D6）给予 300mg iP4。第 16 天，回收生殖道进行胚胎、子宫内膜和黄体（CL）分析。在实验 3 中，在泌乳水牛中，在 TAI 后 3 天（iP4-D3）或 6 天（iP4-D6）给予 300mg iP4 后，评估每个 AI 的妊娠率（P/TAI）和妊娠损失比例。在实验 1 中，两组的血清 P4 浓度均保持在 1ng/mL 以上约 3 天。随后的实验中使用了 300mg 剂量。在实验 2 中，与对照组和 iP4-D6 相比，iP4-D3 组的 CL 重量和子宫内膜腺密度降低，胚胎长度增加（P<0.05）。与对照组和 iP4-D6 相比，iP4-D3 组 CL 中的前列腺素 F 受体（FP）和 ISG15 以及子宫内膜中的 ISG15 和 MX1 的转录丰度更高（P<0.05）。在实验 3 中，在第 30 天和妊娠损失（P>0.1）方面，实验组之间没有差异；然而，与对照组（56.8%）和 iP4-D6（57.7%）相比，iP4-D3 在第 60 天的 P/TAI 较低（41.7%；P=0.07）。总之，在 TAI 后 3 天给予 iP4 会影响 CL 的发育，从而降低水牛的最终妊娠结局。
