Bartlewski P M, Beard A P, Rawlings N C
Department of Veterinary Physiological Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada.
Theriogenology. 2000 Feb;53(3):673-89. doi: 10.1016/S0093-691X(99)00266-6.
Transrectal ultrasonography of ovaries was performed in 11 ewes from Days 10 to 26 and on Day 30 of pregnancy to record the number, size, and position of ovarian follicles > or = 3 mm in diameter and corpora lutea (CL). Transrectal and/or transabdominal ultrasonography of the uterus was performed on Days 10 to 26, 30, 35, 40, 45 and 50 of gestation to ascertain the number and position of the conceptuses. In a second experiment, ultrasonography was conducted in 15 ewes on Days 10, 25, 30, 45 and 50 of pregnancy and from Days 13 to 29 after parturition. Ovarian data were classified into ovaries without CL (Group 1), ovaries with the CL in 1 ovary (Group 2), and ovaries with the CL in both ovaries during pregnancy (Group 3). In early pregnant ewes, the total number of follicles and the diameter of all follicles > or = 3 mm were smaller (P < 0.05) in the CL-bearing ovaries (both Group 2, n = 7 and Group 3, n = 8) than in the non-CL-bearing ovaries (Group 1, n = 7), while the largest follicle diameter was significantly smaller in Group 3 than in Group 1 or 2 ovaries. The number of 3-mm follicles in Group 2 ovaries was lower (P < 0.05) than in Group 1 or 3 ovaries, but the mean number of follicles > or = 5 mm in diameter was significantly lower in Group 3 than in Group 1. The total luteal volume per ovary was higher (P < 0.001) in Group 2 than in Group 3 ovaries of early pregnant ewes. The total follicle diameter and the number of follicles growing from 3 to > or = 5 mm in diameter was lower (P < 0.05) for Group 2 ovaries of ewes that carried twins (n = 3) compared with Group 2 ovaries from ewes with singletons (n = 4). There were no differences in follicular dynamics between Group 3 ovaries and the ovaries of Group 2 in ewes that carried twins. No follicles > 3 mm were seen in the ovaries of postpartum ewes that contained CL during gestation, until Days 21 and 25 postpartum for Groups 2 (n = 10) and 3 (n = 8), respectively, and follicles reaching > or = 5 mm in diameter were detected in only 2 ovaries (Group 2), on Days 27 and 28 postpartum, respectively. We conclude that during early pregnancy in ewes there is a suppression of antral follicle growth which appears to be exerted primarily by the developing conceptus but remains confined to CL-bearing ovaries. Residual local inhibition of follicular development extends into the postpartum period.
在妊娠第10天至26天以及妊娠第30天，对11只母羊进行经直肠卵巢超声检查，以记录直径≥3毫米的卵巢卵泡数量、大小和位置以及黄体（CL）。在妊娠第10天至26天、30天、35天、40天、45天和50天，对子宫进行经直肠和/或经腹超声检查，以确定妊娠产物的数量和位置。在第二项实验中，对15只母羊在妊娠第10天、25天、30天、45天和50天以及产后第13天至29天进行超声检查。卵巢数据分为无CL的卵巢（第1组）、一侧卵巢有CL的卵巢（第2组）和妊娠期间两侧卵巢均有CL的卵巢（第3组）。在妊娠早期母羊中，有CL的卵巢（第2组，n = 7和第3组，n = 8）中卵泡总数和所有直径≥3毫米的卵泡直径均小于无CL的卵巢（第1组，n = 7）（P < 0.05），而第3组中最大卵泡直径显著小于第1组或第2组卵巢。第2组卵巢中3毫米卵泡的数量低于第1组或第3组卵巢（P < 0.05），但直径≥5毫米卵泡的平均数量在第3组中显著低于第1组。妊娠早期母羊中，第2组卵巢每侧的黄体总体积高于第3组（P < 0.001）。与单胎母羊（n = 4）的第2组卵巢相比，怀有双胞胎（n = 3）的母羊第2组卵巢中卵泡总直径以及直径从3毫米生长到≥5毫米的卵泡数量更低（P < 0.05）。怀有双胞胎的母羊中，第3组卵巢和第2组卵巢的卵泡动态没有差异。妊娠期间含有CL的产后母羊卵巢中，直到产后第21天和25天，分别在第2组（n = 10）和第3组（n = 8）中才见到直径> 3毫米的卵泡，且仅在产后第27天和28天，在2个卵巢（第2组）中检测到直径≥5毫米的卵泡。我们得出结论，在母羊妊娠早期，窦状卵泡生长受到抑制，这似乎主要由发育中的妊娠产物施加，但仅限于有CL的卵巢。卵泡发育的残余局部抑制会持续到产后时期。
