Department of Clinical Sciences, Division of Reproduction, Swedish University of Agricultural Sciences-SLU Uppsala, Stockholm, Sweden.
Acta Vet Scand. 2012 Jun 10;54(1):36. doi: 10.1186/1751-0147-54-36.
There is a discrepancy in the reproductive performance between different cattle breeds. Using abattoir-derived ovaries and data base information we studied the effects of breed on in vitro fertilization and early embryo development.
The in vitro developmental competence of oocytes from cattle (n = 202) of Swedish Red (SR), Swedish Holstein (SH) and mixed beef breeds was compared, retrospectively tracing donors of abattoir-derived ovaries using a combination of the national animal databases and abattoir information. Age was significantly lower and carcass conformation score was higher in the beef breeds than in the dairy breeds.Cumulus oocyte complexes (n = 1351) were aspirated from abattoir-derived ovaries from animals of known breed (visual inspection confirmed through databases), age (databases), and abattoir information. Oocytes were matured, fertilized (frozen semen from two dairy bulls) and cultured according to conventional protocols. On day 8, blastocysts were graded and the number of nuclei determined.
Cleavage rate was not different between the breeds but was significantly different between bulls. The percentage of blastocysts on day 8 was significantly higher when the oocyte donor's breed was beef or SR than SH. There was no significant difference in blastocyst grades or stages between the breeds, but the number of nuclei in day 8 blastocysts was significantly lower in SH compared to the beef.
The use of abattoir-derived ovaries from animals whose background is traceable can be a valuable tool for research. Using this approach in the present study, oocyte donor breed was seen to affect early embryo development during in vitro embryo production, which may be a contributing factor to the declining fertility in some dairy breeds seen today.
不同牛种的繁殖性能存在差异。本研究通过屠宰场获得的卵巢和数据库信息，研究了牛种对体外受精和早期胚胎发育的影响。
回顾性分析了屠宰场来源的牛卵母细胞（n=202）的体外发育能力，使用国家动物数据库和屠宰场信息相结合的方法，追溯屠宰场来源卵巢的供体牛种。牛肉品种的年龄显著低于奶牛品种，体况评分高于奶牛品种。从已知牛种（通过数据库和视觉检查确认）、年龄（数据库）和屠宰场信息的屠宰场来源卵巢中抽吸卵丘-卵母细胞复合物（n=1351）。根据常规方案对卵母细胞进行成熟、受精（来自 2 头奶牛的冷冻精液）和培养。第 8 天，对胚胎进行分级并确定核数。
胚胎分裂率在不同品种之间没有差异，但在公牛之间存在显著差异。当卵母细胞供体的牛种为牛肉或瑞典红牛（SR）时，第 8 天的囊胚率显著高于荷斯坦奶牛（SH）。不同品种的囊胚等级或阶段没有显著差异，但 SH 的囊胚第 8 天的核数明显低于牛肉品种。
使用可追溯背景的屠宰场来源卵巢可以作为研究的有效工具。在本研究中，使用这种方法观察到卵母细胞供体牛种影响体外胚胎生产过程中的早期胚胎发育，这可能是导致一些奶牛品种今天生育率下降的一个因素。
