Supplementation of maturation medium with additional granulosa cells has beneficial effect on in vitro maturation of bovine follicular oocytes and their subsequent cleavage and development in vitro. However, maturation system using granulosa cells have some disadvantages that collection of granulosa cells is cumbersome and metabolic activity of the cells is variable according to ovarian cycle or follicular size. We hypothesized that bovine immsture oocytes matured without granulosa cell coculture can fertilize and develop normally if the medium volume per oocyte is reduced during in vitro maturation. Immature oocytes were matured for 24 hours in a TCM199 containing 10% fetal calf serum, anterior pitultary hormone (0.02 AU /ml Antrinⓡ) and estradiol with or without granulosa cells in vitro. In Group 1, 35 to 40 oocytes were matured in a well of 4-well plastic dish containing 500 l of maturation medium and granulosa cells, and 9 to 10 oocytes were matured in a 50-l drop of maturation medium without granulosa cells in Group 2. After maturation, oocytes were coincubated with sperm for 30 hours in a modified Tyrode's medium (IVF). Inseminated oocytes were cultured in a microdrop (30 l) of a synthetic oviduct fluld medium (SOFM) containing BSA, Minimum Essential Medium essential and non-essential amino acids for 9 days. As a preliminary experiment, we investigated the beneficial effect of granulosa cells during maturation on subsequent cleavage and development using the same type of culturedishes (4-well dish). Granulosa cells could not increase embryo cleavage after fertilization but significantly improved (p<0.05) embryo development to expanding blastocyst (Table1 and 2). In Group 1, 68 and 80% of inseminated oocytes have cleaved at 30 hours and 2 days after IVF, respectively, which is similar (p>0.05) to the result of Group 2 (69% at 30 hours and 78% at 2 days after IVF). The oocytes in Group 2 showed 21 and 11% of developmental rates to expanding and hatching blastocysts, respectively, which was not significantly different (p>0.05) from those (20 and 10%, respectively) of oocytes in Group 1. In conclusion, it has been clarified that a microdrop culture system without granulosa cells for in vitro maturation can support bovine embryonic development to blastocyst in vitro as readily as a granulosa cell coculture system.

The objectives of the present study were improvements in the efficiency of developmental rates to morula and blastocyst stages to produce a large number of genetically identical nuclear transplant embryos. The oocytes collected from slaughterhouse ovaries were matured for 24 h and then enucleated and cultured to allow cytoplasmic maturation and gain activation competence. And then the donor embryos were treated for 12 h with 10 g /ml nocodazole and 7.5 g /ml cytochalasin B to synchronize the cell cycle stage at 26 h after the onset of culture. The blastomeres were transferred into the perivitelline space of the enucleated nocytes and blastomeres and oocytes were fused by electrofusion. The cloned embryos were then cultured in various conditions to allow further development. The age of the recipient(30 vs 40 h) had no significant effect on the fusion rates(82.4 vs 82.1%) and the developmental rates to morula /blastocyst(9.8 vs 11.0%). Effect of Nocodazole treatment on the donor cell cyle synchronization to improve the developmental rates of bovine nuclear transplant embryos was significantly higher than control group(21.4 vs 10.1%, p<0.05). Significant differences were in the percentage of fusion rates(72.9,77.1vs 61.9%) in three types of fusion medium(PBS(+), mannitol and sucrose, p<0.01). The developmental rates of bovine nuclear transplant embryos appeared to be highest in mSOF medium under 5% 0 condition, but no significant differences were found when compared with TCM199-BOEC and mSOF under two different oxygen ratio(5 and 20%).

This study was conducted to compare the insemination time of bovine oocytes and determine the effects of glucose(1.5 mM) on the development of bovine embryos at early cleavage stage. Oocytes were matured for 24 h, followed by exposure to sperm and cultured in modified Tyrode's media drops or with bovine oviduct epithelial cell monolayer prepared in TCM199(BOECM). Insemination time and culture system were varied in each experiment. In experiment 1, to investigate the developmental capacity of bovine embryos after different time of exposure to sperm, bovine ova and sperm were co-incubated for 18, 30 or 54 h, respectively. The development to blastocysts of 30 and 54 h insemination groups were significantly higher(P<0.05) than 18 h group, and in case of blastocysts of cleaved embryos, 30 h group were significantly higher(P<0.05) than other groups. In experiment 2, we investigated the effect of glucose on early bovine embryos. After 18 h insemination, in vitro fertilized oocytes were separated following 3 groups ; G+0, C+24 and C+48. Oocytes of G+0 group were cultured in glucose added Tyrode's medium after fertilization, oocytes in C+24 and C+48 groups were cultured in glucose free Tyrode's medium after fertilization. After 24 h culture, G+24 group was moved to glucose added medium. All oocytes of 3 groups were moved to BOECM after 48 h culture. The rates of cleavage and development to blastocysts in G+0 group were significantly lower than other groups. In experiment 3, we determined the effects of glucose exposure from 8 to 20 h after insemination on the cleavage and development of oocytes. The oocytes in glucose added group had high capacity of cleavage and further development. This study shows that in bovine oocytes, the optimal exposure to sperm is 30 h and glucose exposure to bovine one-cell embryos is detrimental to their first cleavage and further development in vitro but there has no evidence of detrimental effect of glucose(1.5 mM) exposure to bovine embryos over the two-cell stage in vitro.

Real time B-mode ultrasound was used to detect the early conceptus in 187 Korean native cattles between days 10 and 60 after last insemination. The ultrasound diagnostic findings were systemically confirmed by palpation per rectum after the 60th day of last insemination. The embryonic vesicle and the embryo proper within the veside were first visible on mean day fl and 23, respectively. The heartbeat of the embryo proper could be detected on day 26, and the limb buds, placentomes, amnion, fetal movement, umbilical cord, optic area and split hooves were first visible on day 33, 34, 34, 44.5, 45, 32 and 48, respectively. The mean length of embryo proper was 3.8mm on day 23 which later increased to 56. 6rnrn on day 60. When ultrasound was used to detect the conceptus between days 20 and 30 after insemination and palpation per rectum after the 60th day of insemination, the accuracy rates of pregnancy detection by ultrasound scanning at days 20, 22, 24, 26, 28, 30 were 44.4, 69.2, 78.6, 87.5, 90.0, 93.3%. In summary, the early pregnancy diagnosis of Korean native cattle with ultrasound appears high accuracy rates. It is considered that ultrasound can be used in veterinary practice well.

The present study was undertaken to examine the critical effect of + concentration on electrostimulation and post-electrostimulation media for electric activation of in vitro matured oocytes of Korean Native Cattle. Oocytes collected from slaughterhouse ovaries were matured in TCM 199 containing FSH, estradiol-17 and FBS with granulosa cell monolayer for 24 hours and denuded with hyaluronidase. And then cumulus-free oocytes were submitted to a DC field of 1.0 kV/cm for 60 sec in electroporation media(0.28 M mannito' and PBS) with different + concentations (0.00, 0.05, 0.10 and 0.15 mM). Stimulated oocytes were stained and examined for pronuclear formation after incuhation in SOF for 12 hours. The rates of pronuclear formation in hovine oocytes electrically stimulated in 0.28 M mannitol with 0.05, 0.10 and 0.15 mM +(60.3, 82.2 and 75.0%) were significantly higher than without +(6.3%) at 12 hours after an electric pulse(p<0.005). The activation rates of Korean Native Cattle oocytes stimulated in PBS supplemented with 0.05, 0.10 and 0.15 mM +(71.0, 75.8 and 75.4%) were significantly higher than without +(23.5%) after post-stimulation incubation(p<0.005). After incubation of oocytes in SOF with and without + following electric stimulation in 0.28 M mannitol with 0.10 mM +, the rates of pronuclear formation of bovine oocytes in +-free SOF(85.7%) was significantly higher than in SOF with 1.71 mM +(62.5%, p<0.05). When oocytes were stimulated in two electrostimulation media supplemented with + and incubated in +-free SOF, there were no significant differences in the rates of pronuclear formation hetween 0.28 M mannitol and PBS. These results indicate that a single electric pulse could induce activation of Korea Native Cattle oocytes in 0.28 M mannitol and PBS supplemented with +. Furthermore, to improve the activation rates, it was hetter that stimulated oocytes were incubated in +-free SOF after electric stimulation than in SOF with +.

The aim of this study was to evaluate the effect of recombinant bovine somatotropin (bST; Boostin-S, LG Chem) treatment with FSH (Super OV) or PMSG on superovulatory response for transvaginal ultrasound-guided oocyte retrieval (TVR) in calves. Eight Korean Native Cattle(KNC) heifer calves; 150 to 240 days old; were randomly assigned to four treatment groups: 1) FSH(75 mg); 2) FSH (75 mg) + bST(500mg) 3) PMSG(1;000 IU); 4) PMSG(1, 000 IU) + bST(500 mg). Experimental calves in group 1 (n=2) and 2(n=2) were weekly superovulated for 4 consecutive weeks with daily injection of FSH for 3days and the next day subjected to TVR session. Animals in group 3 (n=2) and 4(n=2) were weekly stimulated for 4 consecutive weeks with a single dose of 1, 000 IU PMSG. TVR was performed on 72 hours after PMSG injection. Calves in group 2 and 4 was received injection of 500 mg of bST every 10 days. At each TVR session, follicle number and size were recorded; the oocytes collected and graded according to cumulus and cytoplasm investment. Collected oocyte were determined viable oocyte according to morphological quality with granulation of oocyte and number and status of cumlulus cells. IVM and IVF were performed and assessed cleavage rate on day 3 after fertilization. A Sonovet 600(Medison, Co., Ltd) realtime ultrasound scanner with a 6.5 MHz convex transducer, fixed at the tip of 500 mm estended handle equipped with a needle guide was used in collecting oocyte. Differences between groups were analysed by chi-square test. The population of large follicle (5 nun) and aspiration rate were not significant different among the 4 groups. But, the number of small follicles (<5 mm) and aspirated oocyte in the KNC calves treated with bST were 1.3~1.6 times higher than in KNC calves treat with FSH or PMSG alone. In conclusion, the administration of bST with FSH or PMSG at superovulation for TVR in calves was increase the nurnber of small follicle which was influenced the number of aspiratable follicle.

본 실험은 촉진 및 호르몬 측정으로는 알기 힘든 난소의 정상 혹은 병리학적 형태 및 변화를 알아보기 위하여 실시하였다. 실험에서 도살장으로부터 채취된 난소 100개를 수침법으로 초음파 사진을 찍고 그 실제 단면과 비교하였다. 그리고, 홀스타인 50두에서 직장 벽을 통해 난소를 초음파로 관찰하여 난소의 정상 상태 및 병적 상태를 조사하였다. 이 기초 실험을 바탕으로 하여 홀스타인 소 1두를 과배란 처리하여 42일간 난소의 형태 및 변화를 직장 벽을 통해

The present study was performed to investigate the effects of caffeine and heparin on capacitation and acrosome reaction of bovine spermatozoa, effects of antisperm antibodies on acrosome reaction of bovine spermatozoa. The rates of acrosome reaction in control group, caffeine treated group, heparin treated group, caffeine-heparin complex treated group were 40.3, 54.3, 63.3, 72.3%, respectively and there were significant differences among the groups(p<0.01), especially higher in caffeine-heparin complex treated group than the others. The rates of acrosome reaction of antisperm antibodies serum supplemented groups(5, 10 and 20%) were 60.4, 48.9 and 37.1%, respectively and there were significant differences among the groups(p<0.0l), and the more increases in serum concentrations, the more decreases in acrosome reaction, but this phenomenon was not seen in fetal calf serum supplemented group and heifer serum group. When the serum concentration was 5%, the rates of acrosome reactions were significantly lower in fetal calf serum supplemented group than heifer serum group and in antisperm antibodies serum group(p<0.01), and there were no significant differences between heifer serum group and antisperm antibodies serum group(p<0.01). When the serum conecntrations were 10%, 20%, the rates of acrosome reactions were significantly lower in antisperm antibodies serum supplemented group than in fetal calf serum group and in geifer serum group(p<0.01), and there were no significant differences between fetal calf serum group and heifer serum group(p<0.01). These results indicate that caffeine-heparin complex treatment is very effective for inducing acrosome reaction of bovine spermatozoa and that antisperm antibodies block acrosome reaction.

Essential and non-essential amino acids supplemented to culture medium stimulate mammalian embryo development in vitro. Amino acids such as glycine, taurine and alanine are concentrated in the lumen of oviduct and uterus and it can he thought that these amino acids may have physiological role on fertilization and embryo development. Our aim of this experiment was to investigate the effects of essential and non-essential amino acids, taurine or glycine supplemented to fertilization medium on the cleavage and subsequent in vitro development of bovine oocytes matured and fertilized in vitro. Immature oocytes were obtained from slaughtered Holstein cows and heifers and matured in TCM199 containing 10% fetal calf serum, 2.5 g /mL of FSH and LH and 1 g / mL of estradiol with granulosa cells in vitro. After maturation, oocytes were coincubated with sperm in fertilization medium supplemented with Minimum Essential Medium (MEM) essential and non-essential amino acids, taurine (3.75 mM) or glycine (10 mM) for 30 hours in vitro. Inseminated oocytes were cultured in synthetic oviduct fluid medium (SOEM) containing MEM essential, non-essential amino acids and 1 mM glutarnine up to 8 days after fertilization.Supplementation of fertilization medium with MEM essential and non-essential amino acids lowered significantly (p<0.05 and p<0.001) the cleavage rate after 30 hours of IVF (53.3%) and at Day 3 (62.7%: Day 0: the day of I VF) compared to control (64.3% and 77.3%, respectively). Subsequent developmental rates to morulae (Mo) and expanding blastocysts (ExBL) also significantly decreased (p<0.001 and p<0.05 for Mo and ExBL) when oocytes were coincubated with sperm in the medium containing MEM amino acids. Taurine added to fertilization medium have not increased the cleavage rate over the control, whereas glycine showed significantly lower (p<0.01) cleavage rate at Day 3 than that of taurine, but there was no significant difference in the developmental rates to Mo and ExBL of bovine embryos irrespective of the supplementation of taurine or glycine to fertilization medium. In conclusion, supplementation of fertilization medium with essential and non-essential amino acids, taurine or glycine has no beneficial effect on in vitro cleavage and development of bovine oocytes matured and fertilization in vitro.

To examine the critical effect of oxygen concentration on embryonic development, in vitro fertilized embryos were cultured in media(TCM199 vs. SOF) supplemented sera(1O% FCS vs. 10% HS) with and without bovine oviduct epithelial cells under two gas atmosphere (5% in air vs. 5% , 5% , 90% ). Oocytes, obtained from abattoir ovaries, were matured in EGF containing TCM199 medium co-cultured with BOEC for 24 hours, followed by exposure to frozen-thawed, heparin4reated spermatozoa in TALP for 30 hours. And then early embryos(1~2 cell) were cultured in both TCM199 and SOF supplemented with 10% FCS or 10% RS under 5% in air or 5% COi, 5% , 90% . Development to morulae and blastocysts was recorded on days 7, after the start of in vitro fertilization. The developmental rates of in vitro fertilized embryos to morulae and blastocysts cultured in SOF with BOEC under 5% , 5% , 90% (24.4%) were significantly(p<0.05) higher than cultured in SOF with BOEC under 5% in air(14.1%) at seven days after in vitro fertilization. When early bovine embryos were cultured in TCM 199 and SOF under two different gas atmosphere, there were no significant differences in the developmental rates to morulae and blastocysts between supplements of 10% FCS and 10% HS. The rates of development to morulae and blastocysts were significantly(p<0.01) higher in TCM 199 with BOEC(24.7%) than TCM199 without BOEC(10.9%) under 5% in air, otherwise SOF without BOEC(36.4%) were significantly (p<0.05) higher than in SOF with BOEC (24.4%) under 5% , 5% , 90% . In summary, these experiments have proved that the culture system in SOF supplemented 10% ES is effective on in vitro development of early bovine embryos under 5% , 5% , 90% . In addition, it is effective to development of bovine embryos that TCM 199 should be co-cultured with BOEC and SOF should be cultured without somatic cells under two different gas atmosphere.

Production of calves after transfer of nuclear transplant embryos is the latest technology to be applied in commercial livestock breeding. The objective of this study was to establish an efficient procedure to produce offsprings from nuclear transplant embryos. The fusion rates (72.7% vs. 80.8%), cleavage rates (62.5% vs. 71.4%) and rates of development in vitro (12.0% vs. 15.2%) of nuclear transplant embryos were not significantly different between 30 and 40h maturation age of cytoplast. The in vivo and in vitro-derived embryos as nuclei donor were used in this system of bovine nuclear transplantation. Fusion rates of nuclear transplant embryos were not significantly different between in vivo and in vitro-derived embryos (73.0 and 79.2%, respectively). The percentage of embryos reaching the morulae or blastocysts were 21.8% for in vivo-derived embryos and 11.9% for in vitro-derived embryos (p<0.01). Pregnancy rates after embryo transfer of nuclear transplant embryos were not significantly different between in vivo and in vitro-derived embryos (45.9 and 40.5%, respectively). However, calving rates after embryo transfer of nuclear transplant embryos were significantly higher in the in vivo-derived embryos than in vitro (p<0.01). Further research for age of cytoplast and use of in vitro-derived embryos as nuclei donor is required in this system. In conclusion, these results clearly show that the use of in vitro-derived oocytes as recipient cytoplast can improve the nuclear transplant system for genetic progress in cattle.

The objective of this study was to produce calves derived from in vitro fertilization of in vitro matured follicular oocytes. Oocytes aspirated from small antral folicles of ovaries obtained at a local slaughter house were matured and fertilized in vitro. At l8hrs after insemination with Korean native cattle semen, oocytes were co-cultured for 6~7 days by utilizing co-culture system with bovine oviduct epithelial cell. After co-culture, good or excellent quality late morulae or early blastocysts were selected by morphological criteria under stereo microscope. Selected embryos were transferred to recipients on day 6 or 7 (estrus = day 0). Recipients were monitored by observation for estrus and rectal palpation after 60 days from embryo transfer. One of them went to term with the birth of a calf. This case is the first production of calf derived from in vitro fertilization in Korea.

The present study was performed to investigate the effects of co-culture with granulosa cells on in vitro fertilization and cleavage of early bovine embryo development. Bovine oocytes were matured for 20-24 hrs in vitro with granulosa cells or without and then fertilized in vitro using frozen-thawed spermatozoa treated with BO-caffeine, BO-BSA(2OmM heparin added). At l8hrs after insemination, oocytes were fixed and examined or further cultured in TCM 199 for 48hrs. The fertilization rates between the control(70.4%) and the groups of co-cultured with granulosa cell(2.5106 cells/ml; 71.6%, 5.0 106/ml; 71.9%, l.0 107/ml; 71.1%) did not differ significantly. The cleavage rates in the groups co-cultured with granulosa cell(2.5 106 cells/mi; 43.6%, 5.0 106/ml; 46.8%. l.0 107/ml; 45.0%)were significantly higher than that of without granulosa cell, respectively(P<0.05). However there were no significant differences between the groups co-cultured with granulosa cells. The result indicated that co-culture with granulosa cell was effective means to cleavage of bovine follicular oocytes but did not affect the in vitro fertilization.