Related Experiment Video
Updated: Jul 14, 2026

In Vitro Culture Strategy for Oocytes from Early Antral Follicle in Cattle
Published on: July 8, 2020
The relationship between oocyte morphology and ovarian status in cattle
Masashi Nagano1, Mitsugu Hishinuma, Seiji Katagiri
1Laboratory of Theriogenology, Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan. mnaga@muses.tottori-u.ac.jp
Abstract:
We investigated the relationships between oocyte morphology, follicular size and follicular waves using bovine ovaries derived from local abattoirs. Ovaries at the recruitment and selection phases contained larger numbers of oocytes with good developmental ability, although ovaries at the recruitment phase contained the largest numbers of follicles compared with ovaries at the selection and dominant phases. Dominant phase ovaries contained a high percentage of oocytes with as good developmental ability as selection phase ovaries; however, they contained the lowest total number of oocytes with good developmental ability. Small follicles under 3.0 mm in diameter contained large numbers of small and degenerating oocytes. In contrast, follicles more than 3.0 mm in diameter contained a higher percentage of oocytes with good developmental ability.
Related Concept Videos
Oogenesis
Oogenesis
Each primary oocyte is surrounded by a layer of pre-granulosa cells, forming what is known...
Ovarian Cycle
Ovaries
On the ovarian surface, a layer of cuboidal...
Folliculogenesis
Hormonal Control of the Ovarian Cycle
Before puberty, the hypothalamus releases GnRH in a low frequency, low amplitude pulsatile manner. This along with the immature hypothalamic-pituitary-gonadal axis activity, results in low estrogen levels and the absence of a fully functional ovarian cycle. At puberty, GnRH secretion increases in both frequency and...

