• Korean Journal of Animal Reproduction
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• v.23 no.2
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• pp.105-111
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• 1999

The effects of exogenous spleen cells on the progesterone and insulin like-growth factor-I (IGF-I) secretions in luteal cells were studied by using in vitro luteal cell culture system in the Hanwoo luteal cells. The corpora lutea(CL) were collected and pooled from the Korean native cattle(Hanwoo) ovaries from a local slaughter house. After enzymatic dissociation, combined large and small luteal cells(LLC and SLC)(1.0$\times$10$^{6}$ cells/$m\ell$) were incubated in D-MEM media containing antibiotics and 10% FCS. Spleen cells (1.0$\times$10$^{6}$ cells/$m\ell$) obtained from castrated adult male Hanwoo were added to luteal cells and co-cultured for 24 h in the absence or presence of luteinizing hormone (LH) (100 ng). Progesterone contents from luteal tissues were increased at CL-3 stage during each stage of estrous cycle. Progesterone secretion from luteal cell culture by the presence of LH (100 ng/$m\ell$) was positively stimulated compared with control. However, progesterone secretion was not changed by the addition of 5, 10 and 20% of spleen cells in the absence of LH. Co-culture of luteal cells with 10% of spleen cells in the presence of LH(l00ng/$m\ell$) significantly. enhanced after 24 h of culture. IGF-Isecretion from in vitro luteal cells co-culture by the addition of spleen cells (5%, 10% and 20%) was not significantly effected. Besides, in the presence of LH (100ng/$m\ell$), IGF-Isecretions from luteal cells by addition of spleen cells were higher than control media. However, LH alone significantly increased IGF-I secretion at 24 h of culture. These data provide the demonstrate that spleen cells can enhance LH action so as to stimulate progesterone secretion from Hanwoo luteal cells but have no effect to stimulate IGF-I secretion.

• Journal of Embryo Transfer
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• v.21 no.4
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• pp.315-322
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• 2006

This study was performed to investigate the physiological effects of bovine follicular fluid (bFF) or anti-inhibin serum (AI) on follicular development in Hanwoo. Saline (0.95%), bFF or AI (total of 40 ml) were administered into the jugular vein in 9 Hanwoo cows. The plasma inhibin, estradiol-17 $\beta$ (E2), and progesterone (P4) levels were measured using RIA or ELISA kit and the number of ovarian follicles was observed by ultrasonography at 72 hr after ovulation. The plasma inhibin level in bFF treatment group was significantly increased and maintained higher level from 102 hr after ovulation compared to that of saline and AI groups (p<0.05). In plasma E2 level, AI treatment group showed significantly higher level from 36 hr to 108 hr after ovulation than that of saline and bFF groups (p<0.05). After that it showed decreasing tendency. The plasma P4 level was increased in control and AI treatment groups at 68 hr after ovulation. However, it was maintained significantly lower level in bFF group from 84 hr to 180 hr compared to that of saline and AI group (p<0.05). As a result of ultrasonography at 72 hr after ovulation, higher number of follicles was shown in AI treatment group compared to bFF groups, although the difference was not statistically significant. Taken together, it can be postulated that a treatment of synthesized AI inhibits the secretion of inhibin, stimulates FSH secretion inhibited by inhibin, and induces follicular development and estrogen secretion. According to these results, a development of ovarian follicle immediately after ovulation is associated closely with inhibin in Hanwoo heifers.

• Korean Journal of Veterinary Service
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• v.31 no.3
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• pp.397-414
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• 2008

In order to evaluate conception rate of Hanwoo in northwestern region of Gyeongsang-nam-do, we investigated conception rate and reduction of reproductive disorder rate after artificial insemination (AI) in 1,000 heads of breeding cows, This study showed that 80.9% of cows were classified as fertility after 1st and 2nd AI. For a accurate pregnancy diagnosis with practicing ovariectomy and histeotomy, we comparatively investigated each of 80 slaughtered cows, including 30 of non-pregnancy, and used enzyme-linked immunosorbent assay (ELISA) for estimation of plasma progesterone concentration and serum luteal hormone. The mean diameter of non-pregnant corpus luteum is $18.9{\pm}4.2{\times}15.6{\pm}3.6 mm$ and that of pregnant corpus luteum is $22.5{\pm}2.7{\times}18.7{\pm}2.9 mm$. This indicates that corpus luteum is more developed in the ovary of pregnant than non-pregnant cows (P<0.05). The diameter of pregnant corpus luteum according to the stage of pregnancy showed $21.3{\pm}2.4{\pm}18.4{\pm}2.6 mm$ in early stage (1-3 month), $23.4{\pm}2.8{\times}19.1{\pm}2.7 mm$ in middle stage (4-6 month) and $22.8{\pm}3.0{\times}18.8{\pm}2.4mm$, in last stage (7-9 month). This indicates that corpus luteum in middle and last stage is more significantly developed than that of early stage(P<0.05). The mean plasma progesterone concentration of cows showing size of non-pregnant corpus luteum was $4.58{\pm}0.92ng/ml$ and that of pregnant corpus luteum $8.26{\pm}0.98ng/ml$. Thus, it was more significantly increased in pregnant corpus luteum(P<0.02).. However, it was low to $0.58{\pm}0.39ng/ml$. in estrus (corpus albicans). The plasma progesterone concentration according to gestation period was high in proportion to the degree of development in corpus luteum and more significantly increased (P<0.05) and maintained in middle and last state than early state. The concentration was sharply decreased to $0.56{\pm}0.32ng/ml$ at parturition. As a consequence, we can practice the early pregnancy diagnosis by confirming non-pregnancy when the mean plasma progesterone concentration is below 1ng/ml 19 to 22 days after AI and this can be available to diagnose reproductive disorder.

• 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%.

• Journal of Embryo Transfer
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• v.33 no.4
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• pp.265-270
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• 2018

Up-to-date artificial insemination (AI) using frozen sperm consider as the most widely using technology for improvement of Korean Native Cow (Hanwoo) embryo production. However, it is time consuming, required at least 15~20 years to make more than 6 generations, and their offspring number is limited. To overcome such limitations, superovulation and in vitro fertilization have been developed. For superovulation, the number of produced embryos are not enough for commercialization and donor cows need rest period. This led to use of slaughterhouse ovary for in vitro fertilization, but it is impossible to repeat the collection from the same individual and it only can improve the genetic merits of offspring for one generation. Production of embryos using Ovum Pick-Up (OPU) technique, where oocytes can be repeatedly collected from living elite donor, might overcome these limitations. In this study, we investigated the possibility of using OPU technique from donors at different age and different session periods for mass-embryo-production. Oocytes were collected from 26 donor cows twice per week, 3 - 4 months per year, between 2013 and 2016. Results showed that, the average number of embryo produced in first year used donor was significantly higher than that in second year used donor ($3.89{\pm}2.85$ vs $3.29{\pm}2.70$), however, there was no significant difference between third year used donor ($3.51{\pm}3.32$) and other groups. Taken together, our data showed that repeated using of donor up to three years is possible for in vitro embryo mass-production. Moreover, OPU can be used as suitable embryo producing technique for livestock breed improvement.

• Journal of Embryo Transfer
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• v.20 no.1
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• pp.55-62
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• 2005

This study was undertaken to access the effect of collection methods on the collection efficiency, blastocyst rate and pregnancy rate after IVP embryo transfer. The ovaries of Hanwoo were obtained from an abattoir and kept on 25 to $28^{\circ}C$ and transported to laboratory within 4 hrs. The oocytes were collected by aspiration of follicles $(2\~6\;mm)$ with or without slicing of ovaries after aspiration. The oocytes were matured in vitro (IVM) for 20 to 24 hrs in TCM-199 supplemented with $10\%$ fetal bovine serum at $39^{\circ}C$ under $5\%\;CO_{2}$ in air. Following routine IVM/IVF procedure, the oocytes and presumed zygotes were cultured for three day in CRlaa medium with BSA. The cumulus cells at 2 to 8-cell stage of embryos removed then the embryos and were cultured in CRlaa medium containing $10\%$ fetal bovine serum in $5\%\;CO_{2}$ at $39^{\circ}C$. The fresh blastocysts cultured for 7 to 9 days were transferred into recipients. The numbers of oocytes recovered form two different methods, the aspiration and slicing after aspiration, were compared to know what. The number of oocytes per ovary was 8.2 and 6.5 in aspiration combining slicing, and aspiration groups, respectively (p<0.05). The cleavage rate in aspiration method are significantly (p<0.05) high than those in slicing post aspiration $(27.9\%)$, and aspiration $(25.5\%)$. The pregnancy .ate in aspiration method $(62.5\%)$ was high than that in slicing method after aspiration $(54.4\%)$. The pregnancy rates of aspiration method and slicing method after aspiration in nullipara $(58.1\%\;vs\;68.2\%)$ was high than that in pluripara $(49.5\%\;vs\;53.2\%)$. The results obtained that the increased number of oocytes per ovary in slicing method after aspiration could be better than that in aspiration method. Pregnancy rate in aspiration method was slightly higher in than that in slicing method after aspiration.