Departamento de Biociencias Veterinarias, Facultad de Veterinaria, Universidad de la República, Montevideo, Uruguay.
Facultad de Ciencias Veterinarias, Instituto de Ciencia Animal, Universidad Austral de Chile, Valdivia, Los Ríos, Chile.
Reprod Domest Anim. 2024 Nov;59(11):e14744. doi: 10.1111/rda.14744.
These studies aimed to determine if shearing ewes at the second or last third of gestation modify the uterine and placentome blood flow, placentome size, and maternal progesterone concentration. Pregnant ewes were assigned to four groups of 12 ewes each according to the gestation period: mid-pregnancy sheared (on day 90 of pregnancy) or unshorn group; and late-pregnancy sheared group (on day 121 of pregnancy) or unshorn group. In both experimental periods, using spectral Doppler ultrasonography, placentomes and uterine artery blood flow and placentome size were evaluated 14 days before and 6 days after shearing. An additional measurement was performed 26 days after shearing in mid-pregnant ewes. Serum progesterone concentration was measured before shearing 4, 24, 72 h, and 22 days after shearing. The uterine artery's end-diastolic velocity (EDV) tended to be greater in the sheared than in the non-sheared ewes (p = 0.1). Peak systolic velocity (PSV) and EDV of placentome increased (p = 0.05 and p = 0.008, respectively) on day 26, accompanied by an increase in placentome area (p = 0.035) in mid-pregnant ewes. In late-pregnant ewes, uterine artery and placentome blood flow and size did not vary. Progesterone concentration varied with time but was not affected by shearing. In conclusion, shearing triggered an increase in placentome size and some changes in blood flow only when ewes were sheared during the second third of their pregnancy. Shearing ewes either the second or last third of gestation did not affect uterine artery blood flow and progesterone secretion.
这些研究旨在确定在妊娠中期或妊娠晚期剪羊毛是否会改变子宫和胎盘中的血流、胎盘中的大小以及母羊的孕酮浓度。将怀孕的母羊根据妊娠时期分为四组，每组 12 只：妊娠中期剪羊毛（妊娠第 90 天）或不剪羊毛组；和妊娠晚期剪羊毛组（妊娠第 121 天）或不剪羊毛组。在这两个实验期间，使用频谱多普勒超声技术，在剪羊毛前 14 天和剪羊毛后 6 天评估胎盘中的血流和胎盘中的大小以及子宫动脉血流和胎盘中的大小。在妊娠中期的母羊中，在剪羊毛后 26 天进行了额外的测量。在剪羊毛前 4、24、72 小时和 22 天后测量血清孕酮浓度。子宫动脉的舒张末期速度（EDV）在剪羊毛的母羊中趋于大于不剪羊毛的母羊（p=0.1）。胎盘中的收缩期峰值速度（PSV）和 EDV 在第 26 天增加（分别为 p=0.05 和 p=0.008），同时胎盘中的面积增加（p=0.035）在妊娠中期的母羊中。在妊娠晚期的母羊中，子宫动脉和胎盘中的血流和大小没有变化。孕酮浓度随时间而变化，但不受剪羊毛的影响。总之，只有当母羊在妊娠中期的第三阶段被剪羊毛时，剪羊毛才会引发胎盘中的大小和一些血流变化。在妊娠的第二或第三阶段剪羊毛不会影响子宫动脉血流和孕酮分泌。
