This study was performed to improve the development of the in vitro fertilized bovine embryos by the condition of in vitro maturation. COCs were matured in TCM 199 supplemented with 0.1% PVA, 10ng/ml EGF, Hormones (5/ml FSH, 10 IU hCG, 1 /ml estradiol 17-) or granulsa cell+Hormones atmosphere 39, 5% CO2, 95% air for 24hrs. Matured oocytes were fertilized with frozen-thawed semen capacitated with 5mM caffein in BO medium for 20 hrs. IVF embryos were cultured in TCM 199 containing with hormones(same as matured medium), 10% FBS and co-culture with bovine oviduct epitherial cells. Maturation rates of COCs were showed 73.8%, 78.5%, 83.2% and 87.6% respectively, and were significant differences between PVA, EGF, and Hormones, GC+Hormones(p<0.05). The cleavage rates of IVF embryos were revealed 72.5%, 78.4%, 82.3% and 84.2% and showed same tendency as maturation rates(p<0.05). The blastocysts matured by above maturation condition and cultured for 7~10 days after fertilization had 34.4, 43.6, 52.3 and 59.3 cells had no differences among the treatments. These results suggest that high molecules as a substitutes of serum and growth factor may induce nuclear resumption of COCs but we need more study to produce transferable IVF blastocysts by use of that agents.

This study was undertaken with three objectives : to determine the optimal time of blood collection for plasma urea nitrogen(PUN) analysis, to examine the frequency distribution of PUN levels in recipient herd and to relate concentration of PUN to conception rate in Hanwoo recipients. The relationship between PUN level and time postfeeding was examined for 5 individual cows. Mean concentration of PUN rose for 4hrs postfeeding and decreased to PUN level before feeding at 10hrs postfeeding. And then, the blood for PUN analysis was collected at the time before feeding in next experiments. The ratio of cows with PUN concentration of < 12, 12∼18 and 18mg/dl were 50.6, 39.9 and 9.5% in 163 recipients, individually. The pregnancy rate of cows with PUN concentration 12∼16 mg/dl (63.3%) was higher than that of cows with PUN concnetration < 12 mg/dl (46.7%) or > 16mg/dl (42.9%). There results suggest that the PUN test may be beneficial for management of recipient herd in effects to maintain or improve reproductive efficiency.

This study was conducted to investigate the survival and hatching rates after refrozen-thawed bovine IVF blastocysts. The survival rates after refrozen-thawed bovine IVF blastocysts produced on day 7, day 8 and day 9, were 66.6%(16/24), 62.5%(15/24) and 65.3%(17/26), respectively. The survival and hatching rates after the first frozen-thawed bovine JVF blastocysts were 90.0%(27 /30) and 70.0%(21 /30), but in refrozen-thawed bovine IVF blastocysts were 66.2%(49 /74) and 45.9%(34 /74), respectively. The results of this study were suggest that refrozen-thawed bovine IVF embryos had survival ability.

This study was carried out to investigate the effect of equilibration time, sucrose concentration and age of embryo on survival and developmental rates of bovine IVF expanding blastocysts frozen-thawed by direct transfer method. The bovine oocytes were collected from 2~5mm follicles, matured for 20~24hrs in 5% incubator and then fertilized with frozen-thawed semen. Expanding blastocysts at day 7, 8, 9, 10 and 11 after IVF were frozen in 1.8M ethylene glycol(EG). Survival and hatching rates of frozen-thawed IVF embryos were examined. The results were as follow ; Survival and hatching rate of TVF expanding blastocysts after 10, 20, 3Omin exposure in 1.8M EG were 100,0,90.9, 47.1, 85.0, 75.0 and 62.5% respectively. Survival rates of IVF expanding blastocysts frozen with 1.8M EG and various concentration(0, 0.25, 0.5, 1M) of sucrose were 73.3, 25. 0, 16.7, 9.1% respectively. Survival and hatching rates of IVF expanding blastocysts frozen-thawed according to age of embryo(Day 7, 8, 9,10, 11) were 86.1, 84.8, 79.3, 61.4, 51.3, 74.2, 76.9, 71.7, 63.0 and 65.0% respectively. In conclusion, the age of the embryo(Day 7, 8) is very important for the successful freezing of IVF bovine embryos and 1.8M ethylene glycol not containing sucrose may be effective cryoprotectant for direct transfer method.

Three fistulated nonlactating Holstein cows were used to examine the change in ruminal characteristics when fed diets of 100% corn silage, 50% corn silage + 50% wet brewers' grain(WBG) and 100% WBG, and also twenty Holstein heifers averaging 156 3.2kg BW

Since the turn of the century, scientists have earnestly sought to develop a single laboratory assay or combination of laboratory assays which accurately predict the fertility of a semen sample. Most of these assays have focused on evaluating physical characteristics of sperm such as motility, viability, acrosomal integrity and morphology. In recent years new approches have been used to assess the functional aspects of a sperm that are needed to reach the oocyte, fertilize it and contribute to successful embryo development. Among these techniques are the ability of sperm to undergo a heparin induced acrosome reaction and in vitro fertilization, and the affinity of sperm to bind heparin binding protein. Intensification of research efforts in the area of control of sperm fertilizing ability should be a high priority, in view of undoubted benifits both to our basic understanding of sperm fertilizing ability and to our ability to modify it for Al industry.

This study was undertaken to investigate effects of granulosa cells on mejotic maturation of porcine oocytes in vitro. The results obtained in this study were summarized as follows : The germinal vesicle breakdown(GVBD) rates were 91.5, 93.3 and 96.6%, respectively, when the cumulus oocy:e cornplexes(COC) in the TCM-199 medium with sodium bicarbonate, Na pyruvate, penicillin G, streptomycin sulfate and 10% FCS were cultured in the condition of FSH(0.02 Au/ml), LH(10 g/ml) and FSH + LH added. And when the COC were co-cultured with granulosa cell (5 106 cells /ml) in the condition of FSH, LH and FSH + LH added, GVBD rates were 94.3, 92.9 and 98.9%, respectively. However, when the COC were cultured in the condition of hormone free and co-cultured with granulosa cells in the condition of hormone free, the GVBD rates were 40.4 and 86.3%, respectively. The GVBD rates were 41.0, 62.7, 84.6, 88.1 and 93.6%, respectively, when the COC were co-cultured with granulosa cells that the concentrations are 0 cells /ml, 1 106 cells /ml, 5:: 106 cells /ml, 1 107 cells /ml and 5 107 cells /ml.

Glass wool filtration and swim-up method resulted in inreasing to 58.3% and 62.7% of the progressive motility in frozen-thawed boar sperm, compared to 34.2% in the untreated sperm. Glass wool filtration tended to be more successful than swim-up method for the survival sfter incubation of 38.5 for 3h. Sperm recovered by both the swim-up method and the glass wool filtration method were tested in an in vitro fertilization to determine which of the two techniques would yield sperm with high fertilizing capacity. The results indicated that there was a significantly(p

본(本) 연구는 생쥐의 4세포기배(細胞期胚)에서 하나의 할구(割球)를 뽑아내는 새로운 할구분유기술(割球分維技術)인 biopsy에 대한 효율성과 분리(分離)된 수정란(受精卵)과 분리(分離)한 할구(割球)의 생존성 및 새끼생산율을 검토한 결과(結果)이다. 그 결과(結果)를 요약(要約)하면 다음과 같다. 1. 4세포기배(細胞期胚)에서 분리(分離)한 단일해구(單一害球)와 4세포기배(細胞期胚)를 M2 배양액에 배양한 결과(結果), 단일해구(單一害球)는 82.6%가 영양배엽을 형성한 할구(割球)로 발생(發生)하였고 4세포기배(細胞期胚)로 89.5%가 배반포기배(胚盤胞期胚)로 발생(發生)하였다. 2. 4세포기배(細胞期胚)를 biopsy하여 하나의 할구(割球)가 분리(分離)된 수정란(受精卵)과 대조구인 4세포기배(細胞期胚)를 M2배양액에서 배양한 결과 각각 83.3%와 90.4%가 배반포기배(胚盤胞期胚)로 발생(發生)하였다. 3. Biopsy하여 4세포기배(細胞期胚)에서 분리(分離)한 단일해구(單一害球)와 대조구인 4세포기배(細胞期胚)에서 4개의 할구(割球)로 분리한 단일해구(單一害球)를 M2 배양액에서 배양한 결과 각각 80.8% 와 83.3%가 영양배엽을 형성한 할구(割球)로 발생(發生)하였다. 5. 4세포기배(細胞期胚)에서 하나의 할구(割球)를 뽑아낸 수정란(受精卵)과 대조구인 4세포기배(細胞期胚)를 수란생쥐에 이식한 결과 각각 36.0%와 48.6%의 새끼쥐 생산율(率)을 얻었다.