• Journal of Veterinary Clinics
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• v.27 no.1
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• pp.46-49
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• 2010

In this study, we investigated the number of follicles, oocyte recovery rate and oocyte competence after in vitro maturation according to the size of follicle. And equine oocyte competence after in vitro maturation was investigated in terms of the diameter of follicle with criteria of maturation: nuclear stage after Hoechst staining. The average number of follicles per ovary with middle size (11-20 mm, 2.68) was higher than those of small (5-10 mm, 0.74) and large size follicle (> 21 mm, 1.63), therefore medium follicle (53.1%) had higher proportion than other size of follicles. The average numbers of follicle per ovary was 5.05. The rate of oocyte recovery in small (54.5%) and middle follicle (50%) was higher than that in large follicle (40.9%). After culture for 48 h in Medium 199, 50%, 45.5%, and 44.4% of oocytes from the follicles with diameters of 5-10, 11-20, > 21 mm, respectively reached the metaphase II stage. This is the first report showing number of follicle, oocyte recovery rate according to follicular size, and in vitro oocyte maturation in Jeju mare in Korea. To fulfill in vitro equine embryo production, further studies such as the seasonal effect, in vitro fertilization etc is need.

• Journal of Embryo Transfer
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• v.27 no.3
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• pp.141-147
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• 2012

This study was operated to establish induction using ultrasonography by estimating the relation of follicle size and estrus manifestation. Clinical estrus symptoms were observed 97.4% in cows and 87.5% in heifers when overall 55 cows were induced to estrus in a single dose of $PGF_{2{\alpha}}$ after verifying CL through ultrasonography, which means estrus hours among those 52 cows showing the clinical estrus symptoms were estimated 2.39 days on cows and for 2.37 days on heifers which showed no differences (p>0.05). The estrus manifestation hours according to the follicle size in cows didn't have any significance each other (p>0.05), though estrus hours was 54 hours (the shortest) with follicle size bigger than 10 mm and were made up within 69 hours. The estrus manifestation hours according to the follicle size in heifers didn't have any significance each other (p>0.05) and took around 42 hours (the shortest) with follicle size of 5mm (the smallest) and were made up within 66 hours. Follicles after $PGF_{2{\alpha}}$ injection were ovulated and assigned to many phases as follows; Group 1 (growing phase) - continuously growing into ovulation, Group 2 (growing and static phase) - delaying in growth after the growth of follicles, Group 3 (static and growing phase) - growing after growth delay, Group 4 (regressing and new growing phase) - the follicle is closed and a new follicle grows. In addition, the process of follicle development and estrus hours had no significance each other (p>0.05), though estrus manifestation hours in Group 1 and 2 was relatively short, and in Group 3 and 4 for a relatively long time. In the result of all above, the estrus manifestation hours after $PGF_{2{\alpha}}$ injection has no differences accoring to the follicle size in cows and heifers. Therefore, High pregnancy rate is obtained when practicing artificial insemination within 3 days in estrus or TAI in 72 to 80 hours after adminitrating $PGF_{2{\alpha}}$.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.3
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• pp.313-316
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• 2004

Ultrasonographic studies were conducted on eight Murrah buffaloes daily from day 6 postpartum (pp) onwards till day 77 pp to monitor changes in the cervix, uterine horn and ovarian follicular growth and development. The mean size of horn and cervix on day six ($9.07{\pm}0.74$ and $8.58{\pm}0.00cm$) decreased significantly to $4.09{\pm}0.09$ and $3.56{\pm}0.08cm$ by day 27 pp, respectively. Follicles in 50% of the buffaloes ovulated within 24 to 54 days pp and the size of the largest follicle on different days increased to more than 5 mm. The remaining 50 percent of animals ovulated after 65 days postpartum. Large size follicles (>8.5 mm) appeared in six out of eight buffaloes between 10 to 30 days pp and five animals had ovulated during early postpartum period. Waves pattern of follicular growth was observed during early postpartum period. Ovulatory follicles growth rate was more than the anovulatory follicles and increase in size was more as compared to the subordinate follicle. Anovulatory follicles persisted for longer period. Mean size of large follicle was more from day 6 to 41 pp and again from 50 to 65 pp in cyclic animals. Second large follicle were large during early postpartum (18days), thereafter, its size was more in acyclic animals. Small follicles population was less in cyclic animals upto day 50 postpartum. Mean medium size follicle growth pattern did not differ in cyclic and acyclic groups. Large size follicle number was more in cyclic group (5/8) during 14 to 20 days postpartum. Presence of large follicles (>8.5 mm) showed initiation of ovarian activity.

• Journal of Embryo Transfer
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• v.14 no.3
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• pp.177-184
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• 1999

This study was conducted to find out the effect of follicle size and oocyte type on in vitro maturation of poricine follicular oocytes. TCM-HEPEAS medium was used to basic medium, and the oocyte matured in vitro was stained with the Rapid staining method. The results obtained were summarized as follows; 1. The number of follicles an ovary was 20.5. The number of A-and B-typed oocytes an ovary was 2.34. The proportion of A-and b-types oocytes was 40% of the recovery oocytes. 2. Cumulus expanison indexes(CEI) by the follicle size were 1.62∼2.34(<2mm), 1.27∼2.28(2∼5mm) and 1.46∼2.75(>5mm). It was no differ to maturation rate by the follicle size. 3. The degree of oocyte maturation based on oocyte type did not differ for B-and C-typed oocyted but the index of oocyte type A was higher than that of b-and C-typed oocytes. 4. When follicluar oocytes were cultured for 42 hours, the proportion of the Met-II(second metaphase) stage were 22.5% (degree 1), 35.4%(degree 2) and 65.5% (degree 3).

• Korean Journal of Veterinary Research
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• v.36 no.4
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• pp.929-939
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• 1996

The present study was undertaken to establish a relationship between bovine follicle size and oocyte diameter, compare the nuclear maturation competence of oocytes of different diameter groups and the nuclear maturation changes in Korean Native Cattle according to in vitro maturation period. To compare the relationship between follicle size and oocyte diameter, follicles were dissected, measured, and assigned to one of the following size categories($4{\geq}mm$, 3-4mm, 2-3mm, 1-2mm, and < 1mm), investigate the maturation competence in the different-sized oocytes, which were divided into three groups( < $110{\mu}m$, 110 - < $120{\mu}m$, and ${\geq}120{\mu}m$). Oocytes were cultured in the culture medium during 0, 6, 12, 18, and 24hrs, respectively, stained, and measured the nuclear maturation degree according to period. When compared the relationship between follicle size and intrafollicular oocyte diameter, oocyte diameters of three groups of ${\geq}3mm$ follicle-sized were significantly higher than < 3mm (p<0.01). After in vitro maturation, the rates reached to MI stage of < $110{\mu}m$ oocyte groups(25%) was higher than $110-120{\mu}m$ and ${\geq}120{\mu}m$ oocyte groups(11 and 10%) reached to the same stage(p<0.01), and the rates throughout MII stage of $110-120{\mu}m$ and ${\geq}120{\mu}m$ and < $110{\mu}m$(70 and 76%) groups were higher than < $110{\mu}m$(35%)(p<0.01). When nuclear maturation rates were measured according to period, < 6hr groups(7 and 10%) showed lower rates reached to MI than ${\geq}12hr$ groups(100%), 24hr groups(76%) revealed higher rates throughout MII than 18hr groups(40%). These results indicate that the preparation of oocyte for the production of in vitro fertilization embryos and nuclear transplantation ones could be adapted, as follicle increased up to appointed size there was a corresponding increase in oocyte diameter, and differences of nuclear maturation rate revealed according to oocyte diameter and maturation period.

• Clinical and Experimental Reproductive Medicine
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• v.12 no.1
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• pp.83-98
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• 1985

In order to study the mechanism of follicular atresia, the follicles of the porcine ovary were isolated according to the presence or absence of the corpus luteum and their size, and then classified to the normal? or atretic?follicle on the morphological observation such as the transparency, the vascularization of follicle, the nuclear phase of oocyte, and the homogeneity of the granulosa cell layer. The viability of granulosa cells was examined. The concentrations of progesterone ($P_4$), testosterone (T), and estradiol-17 beta ($E_2$) in each follicular fluid were estimated by the radioimmunoassay. The viability of granulosa cells in the atretic follicle was much lower than that of the normal one. The concentration of each steroid hormone increased as the follicular size was increased, was not different in quantity between the normal- and the atretic follicle of which diameter was below 3mm, and were much higher in the atretic follicle than those in the normal one of which diameter was above 7mm. The ratio of the concentration of E2 to T in the large atretic follicle valued higher than that in the normal one, but smaller in the small and medium atretic follicle than that in the normal one. The present study suggests that the mechanism of atresia of the large follicle may be different from that of the small and the medium follicle and that the amount of steroid hormones regarded as the one of the criteria for the atretic follicles.

• Reproductive and Developmental Biology
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• v.35 no.2
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• pp.131-136
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• 2011

The in vitro maturation rate of vitrified-thawed canine oocytes was $30.8{\pm}3.4%$. The in vitro maturation rate of vitrified oocytes was lower than that of the control ($52.0{\pm}2.5%$, p<0.05). The in vitro maturation rate of vitrified-thawed oocytes were significantly (p<0.05) lower than those of fresh oocytes. The in vitro maturation and developmental rates of the vitrified-thawed oocytes were $17.5{\pm}2.5%$ and $8.8{\pm}3.4%$, respectively. This results were lower than the control group ($43.6{\pm}3.2%$ vs $20.0{\pm}3.0%$). SOD1 gene expression of 1~2 mm of follicle size were higher than those of above 6 mm follicle size. SOD2 gene expression of 1~2 mm of follicle size were significantly higher than those of above 6 mm follicle size (p<0.01). The expression pattern of SOD1, 2 was constantly expressed in both groups but strongly expressed in follicles (1~2 mm) group when compared to the above 6 mm follicles. SOD gene expression between groups the fresh and vitrified oocytes groups were significant differences in rates. However, RGS gene expression between groups the fresh and vitrified oocytes groups were no significant differences in rates.

• Clinical and Experimental Reproductive Medicine
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• v.46 no.4
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• pp.197-201
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• 2019

Objective: The aim of this study was to establish whether differences in ovarian size exist between the right and the left ovary of the same individual in women with polycystic ovary syndrome. Methods: In total, 206 Korean women with polycystic ovary syndrome were included in this study. In all participants, a transvaginal or transrectal ultrasound examination was conducted in the early follicular phase of the menstrual cycle. Results: A significant linear correlation was found between the two ovaries with regard to antral follicle count and ovarian volume. The mean antral follicle count in the right ovary (26.75 ± 11.72) was significantly higher than that in the left ovary (23.98 ± 10.85), and the mean volume of the right ovary (11.06 ± 5.17 cm³) was significantly different from that of the left ovary (9.12 ± 4.89 cm³). Conclusion: Ovarian size is different between the right and the left ovary in women with polycystic ovary syndrome.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.12
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• pp.1647-1651
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• 2004

The follicles (1.8 to 7.8 mm in diameter) were recovered from the ovaries in marketed pigs and the number of granulosa cells, the diameter of oocytes obtained from different development stages of the follicles and follicular fluid levels were determined. Correlations between size measurements and cell counts as well as the diameter of antral follicles and oocytes were also investigated. The results indicated that, while expanding in size, follicle numbers decreased with a greater atretic proportion. Granulosa cells increased in numbers continuously and remained unchanged beyond the size of 200 ${mm}^3$ in non-atretic follicles, whereas a sudden drop of granulosa counts was observed in atretic follicles. Follicular fluid, on the other hand, linearly increased its volume with follicle size and differed little between those of non-atretic and atretic follicles. Diameters of oocytes in non-atretic follicles increased to its maximum when follicles expanded to 150 ${mm}^3$ and maintained its size during later follicular expansion. It is concluded that, for in vitro culture, the optimal size of porcine follicle should be between 150 to 180 ${mm}^3$if they are collected from pre-pubertal gilts of marketing size slaughtered in an abattoir.

• Journal of Embryo Transfer
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• v.22 no.3
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• pp.191-194
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• 2007

The purpose of the present study was to set up basic information of size and status of ovaries by using ultrasonography to retrieve in vivo matured oocytes with ovum pick- up method. Ovaries were collected from the abattoir in Jeju in May and June which is breeding season. When the size of ovaries on ultrasonography was compared with real size measured by caliper, no significant difference was shown (p<0.05). The number of preovulatory follicles (>21mm) was investigated with ultrasonography and naked eyes. Ultrasonography group had 0.83 preovulatory follicles per ovary and naked-eye group had 0.75 preovulatory follicle per ovary and their average size was 2.86 cm and 2.34 cm, respectively. The average number of follicle was 4.25 with ultrasonography and 4.38 with naked eyes. There was no significant difference considering the size of follicle and number of follicle between ultrasonography and actual size except for the size of preovulatory follicle, suggesting that information of ultrasonography is able to use for OPU or other reproductive technology of mare.