• Korean Journal of Animal Reproduction
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• v.17 no.2
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• pp.165-171
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• 1993

While ornithine decarboxylase (ODC) is considered a key enzyme in the biosynthesis of polyamines, difluoromethylornithine(DFMO) acts as an inhibitor of polyamine synthesis. Cycling crossbred gilts were randomly assigned to one of two (treatment and control) groups (6/group). An indwelling silicone catheter was surgically implanted in the jugular vein of each animal. DFMO was dissolved in saline(200 mg/ml) and adminstered by i. m. injection at a dose of 80 mg/kg/day. The control group received an equivalent volume saline injection. DFMO was injected 3 times daily(08:00. 16:00. 24:00h) from day 16 of estrous cycle to 21 or until estrus. Once daily blood samples (10ml) were taken from day 14 until two days after the last DFMO treatment. Window blood samples were collected every 15 min for 8 h (from 08:00 to 16:00h) starting on day 16 and continuing until day 21 from one gilt per day. Serum progesterone (P$_4$), estradiol (E$_2$), LH and FSH were measured. Typical concentration profiles for P$_4$ and E$_2$ were seen during the follicular phase regardless of DFMO treatment. Injection of DFMO suppressed the preovulatory LH concentration in the serum(p<0.01) while having no effect on FSH profile. The present results indicate that DFMO had an inhibitory effect on LH secretion in the pig, but did not affect PI, E2 or FSH release.

• Journal of Embryo Transfer
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• v.28 no.1
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• pp.25-30
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• 2013

The aim of this study was to estimate of ovulation time and parturition day at the same time as breeding in small dog by vaginal cytology and to confirm the accuracy by comparing the expected parturition day and the real one. Characteristic features of vaginal cytology during the estrous cycle were the high proportion of large intermediate cell, superficial cell, anuclear cell and erythrocyte in proestrus, superficial cell and anuclear cell in estrus, parabasal cell, small intermediate cell, large intermediate cell and leukocyte in diestrus, parabasal cell and small intermediate in anestrus, respectively. When day 0 was the parturition day, the period of pregnancy is 67.45(64~75) days when the cornification index (CI) is over 90%. Also, on the basis of ovulation day, 63.65(59~66) days was confirmed, and 57.0(52~60) days was confirmed based on the first day of diestrus. There are the gap of 4 days between the day being over 90% in CI and ovulation day. On the basis of this, when expecting parturition day based on the day being over 90% in CI by vaginal cytology, 18.1% was produced in the same of the expected parturition day and the real one, 30.3% and 33.3% were produced in the gap of one day and two days, respectively so, the accuracy within two days was 81.7%. In addition, based on the first day of diestrus, it also was identified to 81.7% as the difference between the expected parturition day and the real one within 2 days. It demonstrated there are any difference between any expected parturition day by vaginal cytology. Thus on the basis of the day of being over 90% CI, it is fully thought to using clinically due to the possibility of prediction the parturition day at the same time as the determination of the proper time of the optimal mating time.

• Korean Journal of Agricultural Science
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• v.12 no.1
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• pp.55-61
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• 1985

This study was carried out to investigate reproductive traits and sex hormone levels by growth in Korean native goats. Serum levels of FSH, LH, prolactin, estradiol-$17{\beta}$ and progesterone were determined every 15 days from the 70 days of age to 190 days by radioimmunoassay. The age and weight at sexual maturity were 183.6 days and 14.3 kg; the length of estrous cycle and estrus period were 20.3 days and 36.7 hours, respectively. The gestation period, litter size and body weight at birth were 148.4 days, 1.4 head and 1.8 kg, respectively. The levels of serum LH were highest with 3.93 mIU/ml at 70 days of age, thereafter decreased gradually to 1.21 mIU/ml at 190 days of age. The concentrations of FSH in serum were below 1.25 mIU/ml throughout the experimental period. The levels of prolactin were lowest with 3.09ng/ml at 85 days of age and highest with 4.65 ng/ml at 175 days of age. The serum levels of estradiol-$17{\beta}$ were increased with age, thus highest with 7.95 pg/ml at 190 days of age. The serum progesterone concentrations were maintained low levels (below 1.0 ng/ml) throughout the experimental period.

• Journal of Embryo Transfer
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• v.17 no.1
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• pp.67-77
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• 2002

This study was carried out to assess the effect of superovulation response and quality of embryos recovered from donor cows after a single subcutaneous injection of FSH dissolved in polyethylene glycol (PEG). Cows were allocated into control and 3 experimental treatment groups. In control, cows were injected intramuscularly 50 mg FSH twice daily for 4 days. Group 1 were injected subcutaneously with a single dose of 400 mg FSH dissolved in 30% PEG solution. Group 2 were injected subcutaneously with a single dose of 200 mg FSH dissolved in 30% PEG solution. Finally in group 3, cows were injected twice 200 mg FSH dissolved in 30% PEG solution by subcutaneous. Superovulation was initiated by injection of FSH between Day 8 and 14 of the estrus cycle (Day 0, the day of estrus), and followed by injection of 25 mg PGF$_2$$\alpha$ at 48 h after first FSH injection. Cows were then artificially inseminated (AI) with semen twice at 48 and 60 h after PGF$_2$$\alpha$ injection. At 7 days after the second AI, embryos collected non-surgically by flushing the uterine horns and were counted and compared morphologically as being transferable and degenerated among different superovulation treatments. Furthermore, progesterone and estradiol -17 $\beta$ in plasma were measured by radioimmunoassay following different treatments at given days All cows of treated groups were observed heat. but control group was showed 77.8%. Superovulation response was observed as 77.8, 87.5, 88.9, and 100% in control, Groups 1, 2 and 3 The mean number of corpus lutea (CL) detected in Group 1 were 19.6, which was, respectively significantly (P<0.05) higher than those of other groups (11.1, 13.4 and 7.6, respectively). However, there did not differ on the mean number of total embryos recovered and of transferable embryos between control and treated groups.

• Development and Reproduction
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• v.5 no.2
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• pp.175-180
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• 2001

The ectopic expression of gonadotropin releasing hormone(GnRH and luteinizing hormone(LH) in several tissues is a quite intriguing phenomenon. Recently, the presence of GnRH and its receptor has been clearly demonstrated in rodents and human mammary gland. In this context, one can postulate that the presence of local circuit composed of GnRH and LH in the gland. The present study was undertaken to elucidate whether there is a correlation between the LH expression in rat mammary gland and physiological status during the process of mammary differentiation. LH contents in mammary gland from cycling to weaning rats were measured by radioimmunoassay(RIA). In cycling rats, changes of the LH level in both serum and mammary gland showed similar pattern as the highest level in proestrus and the lowest level in diestrus II stage. While the serum LH levels were fluctuated from pregnant through involution stage, a sharp decline of mammary LH contents was observed in the lactating rats. This decrement was recovered in involuting rats to the level of proestrus stage. Reverse transcription-polymerase chain reaction (RT-PCR) and Southern blot analyses demonstrated that the transcriptional activities of the mammary LH and GnRH were increased from diestrus I stage to estrus stage, and the increased levels were maintained in pregnant, lactation and involution stages. To test the hypothesis that the alteration in mammary LH expression might be steroid-dependant, ovariectomy(OVX) and steroid supplement model was employed. As expected, supplement of estradiol(E$_2$) after OVX remarkably decreased serum LH level compared to that in serum from vehicle-only treated rats. Likewise, administration of E$_2$ significantly reduced the mammary LH content. The present study demonstrated that (i) the LH expression in mammary gland could be altered by some physiological parameters such as estrous cycle, pregnancy, lactation and involution, and (ii) ovarian steroid especially estrogen seems to be one of major endocrine factors which are responsible for regulation of mammary LH expression.

• Korean Journal of Animal Reproduction
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• v.26 no.2
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• pp.193-199
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• 2002

This study was conducted to investigate the optimal physiologic mating time in Hanwoo for protection to decrease of reproductivity and improvement of production of offspring. We observed 32 cows that were devide into 4 parts of treatment : T1(12 months of age and 0.5kg daily gain), T2(12 months of age and 0.8kg daily gain), T3(15 months of age and 0.5kg daily gain) and T4(18 months and 0.5kg daily gain). The first heat of treated cows was 263.3$\pm$6.4 days and average weight was 181.1$\pm$11.3kg. It was revealed the conception rates of first insemination were 25%(T1), 75%(T4) and number of insemination of T3 and T4(both 1.5) was lower than T1 and T2(2.3 and 2.4). In return of estrus after heifer's first parturition, they(T1, T2, T3 and T4) showed 66.2 days, 76.7 days, 62.4 days and 68.5 days respectively and the average was 65.7 days. Plasma progesterone(P4) concentration was nearly the same during the observation periods of treated cows and P4 was released just after 12 months. Only 5 cows (15.6%) in 32 were showed normal estrus cycle and ovulation before 12 months. Before and after parturition, P4 concentration was decreased fastly and then there was no detection of P4 from after parturition to 40 days after milking. P4 would be released again on 45 day after parturition. The results were summarized as that the optimal mating time of Hanwoo heifers was decided by the 14 months of age, 110 cm height and 265kg weight.

• Journal of Embryo Transfer
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• v.22 no.1
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• pp.69-74
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• 2007

This study was performed to determine the estrous cycles by macroscopic observation of the ovarian changes using the laparoscopy and to make use of these results for embryo transfer in Korean black goat (Copra hircus aegagrus). Laparoscopic examinations of the ovaries were performed from 2 days after $CIDR^(R)$ removal to 22 days after ovulation. The serial morphological changes of follicles and corpus luteum (CL) were observed. CL was classified corpus hemorrhagicum(CH), corpus luteum (CL) and corpus albicans (CA) by its maturation and regression. On the day before ovulation (Day 0), Graafian follicles (GF) were found on one or both ovaries. On the day (Day 1) and $2^{nd}$day (Day 2) of ovulation, and ovulation depression (OD) and an early stage corpus hemorrhagicum $(CH_1)$ were observed at the site of GF, respectively. On Days 3 to 4, more developed and enlarged corpus hemorrhagicum $(CH_2\;and\;CH_3)$ arised from the ovulation of the GF with well vascularization. On Days 5 to 6, it was identified that mature corpus luteum $(CL_3)$ was grown on the ovary, and fully developed CL with adjacent follicles were occupied most part of the ovary on Days 17 and 18. Then the size of CL was diminished, and completely luteal regression $(CL_1\;or\;CA)$ with new large follicle was identified on Days 20 and 22. From these results, the 4 stages of the estrous cycle in Korean black goats were 1) estrus (Day 0) for 1 day, 2) metestrus $(Day\;1{\sim}4)$ for 4 days (stage of CH development), 3) diestrus $(Day\;5{\sim}16/17)$ for 12 or 13 days (luteal stage), and 4) proestrus $(Day\;17/18{\sim}20/22)$ for 4 or 5 days (stage of luteal regression and follicular growing). Laparoscopy for observation of ovarian changes was invasive than laparotomy. Additionally, it had advantages of reduced adhesion and quick operation time. It was considered that laparoscopic examination of ovarian changes will be useful for embryo transfer in the Korean black goats.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.123-123
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• 2003

This study was conducted to determine the ability of nuclear development of canine oocytes depend on the kind of maturation media and addition of serum sources. Ovaries were collected from a bitches at various stages of estrus cycle by an ovariohysterectomy. Oocytes were collected of cumulus oocytes complexes after slicing of ovaries with blade. The maturation medium was containing 0.6 mM/ml cysteine, 0.2 mM pyruvic acid, 20 ng/ml $E_2$ and 1 $\mu g/ml$ rbST Exp. 1, the oocytes were matured in four different maturation medium as follows: 1) TCM-199, 2) DMEM, 3) NCSU37 and 4) modified-NCSU37 with 10% FBS. Exp. 2: the oocytes were matured in mNCSU37 supplemented with different protein sources (10% FBS, 10% EDS, 0.3% BSA and 0.1% PVA) to select the optimal one. Oocytes were matured in a humidified atmosphere containing 5% $CO_2$ at $39{\circ}C$ for 72 hrs. The maturation rate were analyzed by Duncan's multiple range test using General Linear Models procedure in SAS. The rates of meiotic resumption to MI-MII depend on different culture media were achieved with TCM-199 (5.2%), DMEM (5.0%), NCSU37 (7.2%) and m-NCSU37 (5.9%), respectively. The rates of meiotic resumption to MI-MII according to addition of protein source were 10% FBS (13.3%), 10% EDS (25.0%), 0.3% BSA (25.0%) and 0.1% PVA (15.4%), respectively. In conclusion, the results obtained showed that in vitro maturation media and protein supplement to m-NCSU37 culture medium tested did not promote the final steps of IVM in canine oocytes.

• Journal of Embryo Transfer
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• v.17 no.1
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• pp.33-44
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• 2002

These studies were carried out to establish an effective in vivo embryo transfer methods in Hanwoo by analyzing several factors that influence this process. In an embryo transfer, recipients with grade A corpus luteum of the right ovary and that of grade B of the left one showed a higher pregnancy rate(p<0.1) than others. The pregnancy rates of frozen embryos were significantly lower(P<0.01) than those of fresh ones; the former resulting in 35% and the latter resulting in 56.2%. Transfer of embryos according to the estrus cycle(6.0 ∼ 9.0 days) did not show a significant difference in pregnancy rate with fresh embryos recording 45.4 ∼65.7% and frozen ones recording 22.0 ∼ 50.0%. According to the status of corpus luteum and embryo freezing or not, the pregnancy rate was higher on grade A corpus luteum with 40.8 ∼67.9% than B and C which ranged from 25.0∼56.0%. The results of embryo transfer according to the development stage and grade of embryos showed that regardless of the embryo's grade. transfer of morula recorded an average pregnancy rate of 46.3%. This results higher than the transfer of blastocyst which was 34.1%.

• Reproductive and Developmental Biology
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• v.37 no.1
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• pp.35-40
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• 2013

The objective of this study was to investigate the effects of abnormal ovarian cycles after superovulation treatment of Holstein Donor Cows. CIDRs were inserted into the vaginas of twenty two head of Holstein cows, regardless of estrous cycle. Superovulation was induced using folliclar stimulating hormone (FSH). For artificial insemination, donor cows were injected with $PGF_2{\alpha}$ and estrus was checked about 48 hours after the injection. Then they were treated with 4 straws of semen 3 times, with 12-hour intervals. Embryos were collected by a non-surgical method 7 days after the first artificial insemination. The cows were considered to have resumed ovarian cyclicity on the day of ovulation if followed by regular ovarian cycles. Seventy two point seven percentage of the cows(16/22) had normal resumption of ovarian cyclicity(resumption within 40 days after superovulation), and 27.3%(6/22) had delayed resumption(resumption did not occur until>40 days after superovulation). Delayed resumption Type II(first ovulation did not occur until ${\geq}40$ days after superovulation, i.e. delayed first ovulation 13.6%) were the most common types of delayed resumptions. The mean numbers of total ova from < 10 and $10{\leq}$ of corpora lutea(CL) was $7.8{\pm}1.8$ and $12.7{\pm}2.7$, respectively. The number of transferable embryos differed between < 10 and $10{\leq}$ CL was $5.4{\pm}1.3$ and $8.1{\pm}3.4$, respectively. Four point five percentage of the cows(1/22) did not resumption their ovarian cyclicity until 60 days after superovulation treatment. Diverse researches on the superovulation treatment method that is suitable for high-producing Holstein donor cows would contribute to preventing ovarian cyclicity disorder, as well as to the early multiplication of cows with superior genes by increasing the utilization value of donor cows.