Maciel M, Gustafsson H, Rodriguez-Martinez H
Department of Obstetrics and Gynaecology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, Uppsala.
Zentralbl Veterinarmed A. 1995 Apr;42(2):123-9. doi: 10.1111/j.1439-0442.1995.tb00363.x.
To determine the influence of a dominant follicle on the superovulatory response in midlate lactating cows, the dynamics of follicular growth and the development of corpora lutea and embryos were studied. Real-time B-mode ultrasonography with a 7.5 MHz rectal linear-array transducer was used to scan the ovaries daily, from 8-12 days before superovulation until day 7 post-estrus, when embryos were recovered. On the first day of superovulation cows were classified as belonging to either a 'dominant' group (n = 12) having a 'dominant follicle', i.e. > 9 mm in diameter in growing phase or stable for < 4 days, or a 'non-dominant' group (n = 11) those carrying a 'non-dominant follicle', i.e. a follicle in a regressing phase or with the same diameter for > 4 days. Cows in the 'dominant' group had significantly higher numbers of 4-6 and 7-10 mm follicles than cows in the 'non-dominant' group on the third and the fifth day of superovulation. The total number of follicles (> 4 mm) preovulation and the number of CL day 7 postovulation was higher in the 'dominant' group than in the 'non-dominant' group. There were no differences between groups regarding the total number of embryos or transferable embryos recovered. The results indicate that superovulation in mid-late lactation is not negatively affected by the presence of a 'dominant follicle'. The criteria to define 'dominant' and 'non-dominant' follicles might be redefined when applied to lactating cows, whose response to superovulation seems to be under the influence of many other factors.
为了确定优势卵泡对泌乳中后期奶牛超数排卵反应的影响，研究了卵泡生长动态以及黄体和胚胎的发育情况。使用配备7.5 MHz直肠线性阵列探头的实时B型超声仪，从超数排卵前8 - 12天开始，每天对卵巢进行扫描，直至发情后第7天回收胚胎。在超数排卵的第一天，奶牛被分为“优势”组（n = 12）和“非优势”组（n = 11）。“优势”组奶牛有一个“优势卵泡”，即处于生长阶段直径大于9 mm或稳定期小于4天；“非优势”组奶牛有一个“非优势卵泡”，即处于退化阶段或直径相同超过4天。在超数排卵的第三天和第五天，“优势”组奶牛4 - 6 mm和7 - 10 mm卵泡的数量显著多于“非优势”组奶牛。排卵前卵泡总数（> 4 mm）和排卵后第7天黄体数量，“优势”组高于“非优势”组。两组回收的胚胎总数或可移植胚胎数量没有差异。结果表明，泌乳中后期的超数排卵不受 “优势卵泡” 存在的负面影响。当应用于泌乳奶牛时，定义“优势”和“非优势”卵泡的标准可能需要重新定义，因为泌乳奶牛对超数排卵的反应似乎受到许多其他因素的影响。
