The relationship between oocyte morphology and ovarian status in cattle.
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.
Nagano
Masashi
M
Laboratory of Theriogenology, Department of Veterinary Clinical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Sapporo, Japan. mnaga@muses.tottori-u.ac.jp
Hishinuma
Mitsugu
M
Katagiri
Seiji
S
Takahashi
Yoshiyuki
Y
D000818:Animals; D002417:Cattle; D002452:Cell Count; D005260:Female; D005307:Fertilization in Vitro / Q000662:veterinary*; D009865:Oocytes / Q000166:cytology*; D006080:Ovarian Follicle / Q000166:cytology*