Changes in the number of follicles and of oocytes in ovaries of prepubertal, peripubertal and mature bitches.
Ovaries were collected from prepubertal (< 6 months of age, n = 4 ovaries), peripubertal (6 to 10 months of age, n = 12 ovaries) and mature (> 10 months, n = 12 ovaries) bitches after routine ovariohysterectomies and fixed in formalin. Ovaries were bisected, embedded in paraffin wax and 20 serial sections were made at intervals of 10 microns. Sections were stained with haematoxylin and eosin to examine follicles and oocytes in a cross-section of cortex of known size. Counts were made on all sections, resulting in examination of the entire cortical area present in the sections. Oocytes were counted and classified as nucleate or anucleate. Follicles were counted and classified as large (> 100 microns in diameter) or small (< 100 microns in diameter), containing one oocyte (monovular), more than one oocyte (polyovular) or no oocytes (anovular). It was concluded that at first oestrus there was an increase (P < 0.05) per section in number of total oocytes and small monovular follicles and a significant increase (P < 0.05) in the number of nucleated oocytes in monovular follicles, suggesting that oogenesis or folliculogenesis is still occurring at this age. At pre- and peripubertal ages polyovular follicles were found which persist into maturity. There was no difference in numbers of anovular follicles and total number of polyovular follicles among different age groups.
McDougall
K
K
Department of Biomedical Sciences, University of Guelph, Ontario, Canada.
Hay
M A
MA
Goodrowe
K L
KL
Gartley
C J
CJ
King
W A
WA
D000818:Animals; D002452:Cell Count; D004285:Dogs / Q000502:physiology*; D005260:Female; D009865:Oocytes / Q000166:cytology*; D009866:Oogenesis / Q000502:physiology; D006080:Ovarian Follicle / Q000033:anatomy & histology*; D012741:Sexual Maturation / Q000502:physiology*