• Korean Journal of Veterinary Research
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• v.34 no.2
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• pp.395-406
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• 1994

To study the conditions to enhance success of embryo transfer in the dog, 20 mixed-breed bitches were used for the experiment along with 4 male dogs for mating. The bitches were paired according to synchronism of natural estrus, or the counterpart as donor or recipient was treated with gonadotropin as FSH (follicular stimulating hormone) or PMSG (pregnant mare serum gonadotropin) for induction of estrus to be synchronized with estrus of the other bitch in natural estrus. Embryo recovery was performed in two ways for comparison, either by flushing each uterine horn after ovariohysterectomy or by flushing each horn in the state of non-ovariohysterectomy. In addition, the result of pregnancy according to the embryo stage and the repeatability of the experimental animals as donor or recipient were also investigated. FSH or PMSG was administered to the bitches which had passed over 4 months from last estrus, resulting in estrus-positive in 3 dogs of 6 FSH-treated dogs (50.0%), and in 5 dogs of 9 PMSG-treated dogs (55.6%), determined by proestrus signs and vaginal smear test. Estrus-positive bitches induced with gonadotropin were used as donor or recipient resulting in one embryo-recovered bitch as donor and one offspring-delivered bitch as recipient in 5 PMSG-treated dogs, whereas no result was obtained from 3 FSH-treated dogs. The rate of embryo recovery to be compared with number of corpus luteum was 68.2% in ovariohysterectomized dogs and 55.2% in non-ovariohysterectomized dogs, respectively. The number of dogs from which embryo was collected were 4 dogs of 6 ovariohysterectomized dogs (66.7%) and 6 dogs of 7 non-ovariohysterectomized dogs (85.7%), respectively. The result of parturition was obtained from one dog of 5 estrus-induced recipients, whereas no result was obtained from 3 natural-estrus recipients. The only dog which delivered a male puppy had been transferred 3 morulae and 2 blastocysts. Of 6 repeat-used bitches in canine embryo transfer, 3 dogs showed repeatability either as donor or recipient. These results indicated that inducing estrus of a dog with gonadotropin is feasible in canine embryo transfer to be synchronized with that of a natural-estrus dog, that embryo recovery is also possible in non-hysterectomized dogs, that the estrus-induced dog is also usable as recipient to result in parturition, and that repeat-use of a bitch as donor or(and) recipient is possible in canine embryo transfer.

• Journal of Embryo Transfer
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• v.21 no.3
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• pp.241-245
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• 2006

This study was carried out to investigate the effect of intra-uterine infusion of lipopolysaccharide (LPS) on reproductive performance in lactating dairy cows. Conception rate at first service was higher (56.0%) in dairy cows treated with LPS compared to non-treated cows (20.0 %). Cumulative conception rate by overall services (more than 2 services) after LPS treatment was also higher (64.0%) in dairy cows treated with LPS compared to non-treated cows (40.0%). Services per conception was significantly higher in control ($2.0{\pm}0.1$) compared with LPS ($1.2{\pm}0.4$) treated group (p<0.05).

• Journal of Veterinary Clinics
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• v.20 no.3
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• pp.376-383
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• 2003

To establish the differential diagnosis and treatment method in bovine ovarian cysts, specially ovarian cysts with corpus luteum, serum progesterone concentration, rectal palpation and ultrasonography for measuring the cystic wall thickness and diameter of cyst and corpus luteum were investigated from 1,188 dairy cows with ovarian cysts. The plasma progesterone concentrations were 0.3$\pm$0.4 (mean$\pm$SD) ng/ml in 629 cows with follicular cysts, 3.7$\pm$1.1 ng/ml in 431 cows with luteal cysts, and 3.8$\pm$1.2 ng/ml in 128 cows with coexist of ovarian cysts and corpus luteum, respectively. The cystic wall thickness by ultrasonography were 1.6$\pm$0.4 mm in 629 cows with follicular cysts, 4.2$\pm$1.5 mm in 431 cows with luteal cysts, and 1.6$\pm$0.6 mm in 128 cows with coexist of ovarian cysts and corpus luteum, respectively. The days from initial treatment to insemination in follicular cysts were 28.1$\pm$6.9 days in treatment of GnRH alone, 15.9$\pm$2.9 days in combination of GnRH and dinoprost, and 15.1$\pm$3.1 days in combination of GnRH and cloprostenol. The percentages of cows conceived within 100 days after initial treatment were 61 %, 68% and 73% in treatment of GnRH alone, combination of GnRH and dinoprost, and combination of GnRH and cloprostenol, respectively. The days from initial treatment to insemination in luteal cysts were 3.8$\pm$0.6 days in treatment of dinoprost alone and 3.8$\pm$0.7 in cloprostenol alone. The percentages of cows conceived within 100 days after initial treatment were 69.5% and 68.5% in treatment of dinoprost and cloprostenol, respectively. The days from initial treatment to insemination in coexist of cysts and corpus luteum were 3.7$\pm$0.7 days in treatment of dinoprost alone and 3.8$\pm$0.6 in cloprostenol alone. The percentages of cows conceived within 100 days after initial treatment were 87% and 84% in treatment of dinoprost and cloprostenol, respectively. These results suggest that the best choice for treatment agents in ovarian cysts were combination of GnRH and PGF$_2$$\alpha$ in follicular cysts, and the PGF$_2$$\alpha$ in luteal cysts and in coexist of cysts and corpus luteum, respectively. In conclusion, it is suggest that ultrasonography is useful diagnostic tool for diagnosis and selection of treatment remedy in cystic ovaries of bovine.

• Korean Journal of Agricultural Science
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• v.12 no.1
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• pp.70-74
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• 1985

Serum levels of LH, FSH, prolactin, estradiol-$17{\beta}$ and progesterone were investigated every 20 days after the day of mating for the period of 140 days, at the day of parturition and thereafter 10 th and 20th day postpartum in Korean native goats. Serum levels of LH were highest with 1.95 mIU/ml at the 60 days after gestation, but maintained high levels until 100 days after gestation, and thereafter decreased gradually to 0.02 mIU/ml at the day of parturition. Prolactin concentrations increased from the 140 days after gestation, and showed highest levels with 29.75 ng/ml at the day of parturition, then decreased gradually. FSH levels determined were below 1.25 mIU/ml during the experimental period. Estradiol-$17{\beta}$ concentrations increased gradually from 7.51 pg/ml at the 20 days after gestation to 159.62 pg/ml at the day of parturition, and decreased rapidly after parturition. Progesterone levels were highest with 6.62 ng/ml at the 120 days after gestation, the decreased rapidly to 1.25 ng/ml at the day of parturition.

• Journal of Veterinary Clinics
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• v.19 no.4
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• pp.418-425
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• 2002

Estrus was induced in 13 anestrus Korea Jin-do bitches by intramuscular injection of pregnant mare serum gonadotropin (PMSG) in a dose of 500 lU once daily for ten consecutive days, followed by an additional single intraveneous injection of 1,000 lU of human chorionic gonadotropin (hCG) on the tenth day. Day-changes of vaginal epithelial cells during the hormone treatment were investigated in each experimental bitches and compared with the those of spontaneous estrus bitches. The first days of vulval bleeding and male acceptance after PMSG treatment were on Day 6.0$\pm$ 1.5 (mean$\pm$ SD) and Day 9.0$\pm$ 1.9, respectively. And in all of 13 bitches, vulval swelling and perineal reflex were shown. The mean durations of proestrus and estrus were 2.9$\pm$ 1.4 (mean$\pm$ SD, range ; 1-6) and 11.5: 1.7 (range ; 8-14) days, respectively, that is, duration of proestrus was significantly shorter than that of the spontneous estrous bitches but duration of estrus was longer than that of the spontaneous estrous bitches. Characteristic features of vaginal cytology during the estrous cycle were the high proportions of large intermediate cell, superficial cell, anuclear cell and erythrocyte in proestrus, superficial cell and anuclear cell in estrus and parabasal cell, small intermediate, large intermediate cell, and leukocyte in diestrus, respectively. The comification index (Cl) was significantly high proportion in proestrus and estrus, when Day 0 was timed from the first day of male acceptance, the Cl was first increased above 80% on Day 0 and maintained above 80% until Day 0 to Day 5 during 6 days and showed a peak on Day 2. Also it was maintained above 90% until Day 2 to Day 3 during 2 days. These results indicated that all 13 ekperimental bitches showed positive estrus detection by the estrus behavior and vaginal smear test after treated with PMSG and hCC. It suggested that vaginal cytology was used to estimate the optimal mating and ovulation time, in consideration of the day when the Cl was maintained above 80% in estrus-induced Korea Jin-do bitches.

• Korean Journal of Agricultural Science
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• v.28 no.2
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• pp.85-91
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• 2001

This study was carried out to investigate the effects of liquid boar semen on reproductive performance in swine artificial insemination. Many factors, which were breeds, time of insemination, breeding season, sperm per dose etc, have been tried to improve reproductive efficiency. Boars were raised at Swine Artificial Insemination Center in National Livestock Research Institute, Sunghwan, Chungnam, Korea. This experiment was carried out from 1995 to 2000. There were no differences in the fertility results compared with 3 breeds (Landrace, Yorkshire and Duroc), frequencies of artificial insemination (double and triple) per estrus cycle and different seasons by using liquid boar semen. There were no significant differences in conception rate, farrowing rate and litter size using 4 trials of 3.0, 2.5, 2.0 and $1.5{\times}10^9/80ml$ in liquid boar semen with 70% of motile sperm cells. We confirmed that the sperm number per dose of $1.5{\times}10^9/80ml$ could be used for commercial artificial insemination.

• Journal of Embryo Transfer
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• v.18 no.1
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• pp.27-33
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• 2003

The study was carried out to investigate the effects of morphology, reproductive cycle, incubation time and activation of oocytes in vitro maturation of canine oocytes and development of canine IVM/IVF embryos. The results were summarized as follows: 1. The developmental rates to 16 cells of fresh, salts and 4$^{\circ}C$-stored oocytes with and without cumulus cells were 14.3%, 5.0% and 7.5%, 2.8% and 5.7%, 0.0%, respectively. The rate of oocytes with cumulus cells(5.7%~14.3%) was higher than that of denuded oocytes(0.0%~5.0%). 2. The developmental rate to If cells of in vitro cultured oocytes recovered from ovaries collected at different stages of the reproductive cycle were 0.0%, 10.7%, 1.5%, respectively. 3. The developmental rate to 16 cells of fresh oocytes with cumulus cell cultured for 24, 32 and 48 hrs in $CO_2$ incubator were 0.0%, 5.3%, 11.8%, respectively. The rate of oocytes cultured for 48 hrs was higher than that oocytes cultured for 24 and 32 hrs. 4. The development to If cells treated activation and non-activation oocytes were 15.0%, 6.7%, respectively. The rate of oocytes treated activation was higher than that oocyte treat non-activation.

• Korean Journal of Animal Reproduction
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• v.26 no.2
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• pp.95-104
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• 2002

This study was performed during the four seasons for the production of transgenic pigs containing the human erythropoietin(hEPO) transgene. Purebred Landrace gilts and sows approximately 8∼15 months of age (n=42) were used fur the collection of 1-cell zygotes for DNA microinjection and transfer. Retrospectively, estrus synchronization and superovulation schemes were evaluated to assess practicality for zygote collection. Synchronization and superovulation procedures were used that cyclic gilts were synchronized with 20mg altrenogest (ALT) per day for 9days after PG600 administration followed by superovulation with 1500IU pregnant mares serum gonadotropin (PMSG) and 500IU human chorionic gonadotrophin (hCG). Preparation of recombinant gene for microinjection is mice whey acidic protein promoter (mWAP) linked to human erythropoietin (hEPO) gene. After hormone treatment, 650 embryos were collected from 23 donors and 83.1% (540/650) embryos were in 1-cell stage which can be visualized the pronuclei for DNA microinjection. A total of 543 DNA microinjected embryos fiom donors were transferred to 19 synchronized recipients, seven of them maintained pregnancy and delivered 47 piglets. One of the 47 offsprings were determined to have transgene by PCR analysis. The overall rate of transgenic production was 2.13% (tansgenic/offspring). This study provides the success and useful information regarding production of transgenic pig for bioreactor research.

• Korean Journal of Animal Reproduction
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• v.26 no.2
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• pp.87-94
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• 2002

This study was performed during the four seasons for the production of transgenic pigs containing the Cellulase Digest Gene. Purebred Landrace gilts and sows approximately 8∼15 months of age (n=126) were used for the collection of 1-cell zygotes for DNA microinjection and transfer. Retrospectively, estrus synchronization and superovulation schemes were evaluated to assess practicality fur zygote collection. Synchronization and superovulation procedures were used that cyclic gilts were synchronized with 20mg altrenogest (ALT) per day for 9 days after PG600 administration followed by superovulation with 1000 IU pregnant mares serum gonadotropin (PMSG) and 750IU human chorionic gonadotrophin (hCG). The cellulase digestion gene for microinjection is rat elasterase promoter (rEl) linked to CelD gene. After hormone treatment, 1,422 embryos were collected from 91 donors and 95.6% (1,359/1,422) embryos were in 1-cell stage which can be visualized the pronuclei for DNA microinjection. A total of 725 DNA microinjected embryos transferred into 35 recipients and produced 65 piglets from 13 litters. Pregnancy rate according to the number of transferred embryos to recipients was higher the group which received 21 to 24 embryos (50.0%) than other groups 20.0% in less and 33.3% in more. A tail tissue was collected from 65 piglets for biopsy. PCR screening was performed on each DNA sample using two separate sets of primers specific for the 5'- and 3'-flanking region of the rEl-CelD gene. Five of the 65 piglets (7.69%) were positive for the transgene. This study provide useful information regarding production of transgenic pig for bioreactor research.

• Korean Journal of Animal Reproduction
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• v.26 no.2
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• pp.111-117
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• 2002

This study was carried out to investigate the effects of frozen boar semen on reproductive performance in swine artificial insemination (AI). Many factors, which were breeds, time of insemination, sperm concentration per dose, farm and year were investigated to improve reproductive performance efficiency. Boars were raised at Swine Artificial Insemination Center in National Livestock Research Institute, Sunghwan, Chungnam, Korea. This experiment was carried out from 1995 to 2000. There were no differences in swine AI with frozen boar semen using 5$m\ell$ maxi-straw among 3 breeds (Landrace, Yorkshire, Duroc), 2 or 3 times insemination per estrus, and 3 different sperm numbers of 3.0, 4.0, and 5.0$\times$10$^{9}$ per dose of insemination. However, non-return rate and litter size of sows inseminated with frozen boar semen of commercial farms were different according to farm management system and inseminator's skill. Conception rate, farrowing rate and number of pigs born alive per litter by artificial insemination with frozen boar semen (5$m\ell$ maxi-straw) from 1995 to 1999 was 68.3~74.6%, 61.7~67.6% and 8.1~8.7 heads.