• Journal of Embryo Transfer
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• v.33 no.3
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• pp.149-157
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• 2018

The objective of this study was to evaluate the effect of treating dairy cattle with exogenous human chorionic gonadotrophin (hCG), five (5) days post artificial insemination (AI) on serum progesterone (P4) concentration and pregnancy rate. In this experiment, five days after AI, cows were assigned randomly to two groups namely: a) treated group (67) which were administrered with 1500 IU hCG (Chorulon) and b) control group (61), which received no treatment. On day 5, 10, 15 and 20 after the artificial insemination, blood samples from a total of 8 cows (4 from each group) were collected and were analyzed for serum P4 concentration. Cows were detected for estrus according to standing heat by visual observation. Cows that were detected still in estrus after days 18-24 were re-inseminated and recorded as not pregnant (open). Pregnancy diagnosis was conducted by ultrasonographic examination and transrectal palpation of the uterus on approximately 60 days in cows that observed to be not in estrus. The conception rate in hCG treated and control groups were 52.5 and 36.1%, respectively. The results proved that there were no significant differences in conception rate between two groups (p=0.0568). However, pregnancy rates were reduced by hCG treatment. Average serum P4 concentrations did not differ between Hcg-treated and control groups on day 5 (0.377 versus 0.375 ng/ml). On day 20 serum P4 concentrations were greater in the treated group compared with the control group (3.085 versus 2.010 ng/ml). The treatment with hCG seemed to increase P4 level compared with the control. In conclusion, the results of this study showed that 1500 IU of hCG administered on 5 day post AI increased conception rate in dairy cows. This was supported by the results on serum P4 concentration which was greater in hCG treated group.

• Reproductive and Developmental Biology
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• v.30 no.3
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• pp.213-218
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• 2006

This study was conducted to investigate the effect of abnormal ovarian cycle postpartum on subsequent reproductive performance of Holstein cows. The cows were considered to have resumed ovarian cyclicity on the day of ovulation if followed by regular ovarian cycles. Total 58.8 percentage of the cows(l14/194) had normal resumption of ovarian cyclicity(resumption within 40 days after calving), and 41.2%(80/194) had delayed resumption(resumption did not occur until >40 days after calving). Delayed resumption Type I(one or more ovarian cycles with luteal phase >20 days, i.e. prolonged luteal phase; 17.5%) and delayed resumption Type II(first ovulation did net occur until $\geq$40 days after calving, i.e. anovulation 22.7%) were the most common types of delayed resumptions. When compared with cows with a normal ovarian cycle, the cows of delayed resumption Type I had a lower 100 days AI submission conception and pregnancy rates(84.2% vs 40.0%; p<0.01, 24.0% vs 21.4% and 20.2% vs 11.1%, respectively), and longer intervals to first AI and to conception($64.7{\pm}2.79$ days vs $105.7{\pm}7.48$ days and $105.1{\pm}7.16$ days vs $133.7{\pm}11.17$ days, respectively; p<0.01). Similarly, when compared with cows with normal ovarian cycles, the cows of delayed resumption Type II had lower 100 days conception and pregnancy rates(24.0% vs 20.0% and 20.2% vs 16.3%, respectively), and longer intervals to first AI and to conception($64.7{\pm}2.79$ days vs $72.6{\pm}4.45$ days and $105.1{\pm}7.16$ days vs $120.8{\pm}12.33$ days, respectively). In conclusion, abnormal ovarian cycles postpartum adversely affected reproductive performance, including AI submission rate, pregnancy rate, interval to first AI, and calving to conception interval in Holstein cows.

• Journal of Embryo Transfer
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• v.19 no.1
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• pp.53-59
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• 2004

The environmental impact of nutrient waste from agriculture has become an area of concern as ways to produce more food and of offspring. In dairy cattle, as the genetic capacity for milk production has increased, decreased fertility has become a severe problem by feeding high dietary protein, resulting in high concentration of blood urea nitrogen (BUN). There are numerous reports on BUN which is associated with reduced conception rates and closely related to body condition score (BCS) in lactating cattle, but not in Korean native cattle. This study was therefore performed to investigate the relation of BUN to both BCS and conception rates in Korean cattle. A total of 400 female Korean cattle (2∼5 years) in Daewanryong were used for this experiment. Feeding condition divided into two groups depending on grazing and darn feeding period. In grazing period, the mixture of Timothy, Orchard grass and Tall fescue, and concentrates (2.5 kg/day) was fed whereas hay (6.5 kg/day) and corn silage (20 kg/day) were fed while barn feeding period. Average BUN concentration at grazing and barn feeding were 7.39$\pm$2.65 mg/㎗ and 12.36$\pm$2.92 mg/㎗, respectively. During grazing period, high rates of pregnancy showed at 4∼8 mg/㎗ BUN concentration. In barn feeding period, 66%, of cattle were in pregnant at 8∼l4 mg/㎗ BUN concentration. The BCS for obtaining high rate of pregnancy raged at 2.5∼3.5. However, BUN did not directly relate to BCS in Korean cattle.

• Korean Journal of Animal Reproduction
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• v.18 no.1
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• pp.55-62
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• 1994

This study was carried out to test the effects of fluorescein diacetate(FDA 0${mu}ell$/ml, 0.5${mu}ell$/ml, 5${mu}ell$/ml, 10${mu}ell$/ml or 0${mu}ell$/ml, 5${mu}ell$/ml in PBS) treated before culture on the survival of vitrified mouse morulae in vitrification solution(20% glycerol＋glycerol＋10% ethylene glycol＋30% ficoll＋10% sucrose). The results were summarized as follows; 1. The survival rate of FDA-tested fresh mouse morulae after 24 hours culture was over 96%((P4.8) in the control or treatment groups with various levels of FDA. Because the rate of mouse morulae which developed to hatched blastocysts was higher with the various levels of FDA treatment(67%) than control(50%), it was considered that toxicity of FDA did not affect the survival of mouse morulae. 2. When mouse morulae were FDA-tested in FDA 0(control), 0.5, 5, and 10${mu}ell$/ml treatment after vitrification, the development rate to expanded blastocyst were 66, 82, 64 and 76%, and FDA scores were P4.2(84%), P4.7(94%), P4.2(84%) and P3.9(78%), respectively. There were no significant differences between control and FDA treatments, but there were significant difference between 0.5${mu}ell$/ml)94%) and 10${mu}ell$/ml(78%) treatment(P<0.01). 3. The survival rates of cultured mouse morulae according to FDA-scores(P0=non-fluorescence; P1~P5=according to their fluorescence) after vitrification were P5;92%, P4;67%, P3;42% and P2.P0;0%, respectively. 4. Implantation rates of morulae stage embryos cultured into early blastocysts and implanted into uterine hornes vitrification were 14 and 11% embryos treated control(0${mu}ell$/ml) and FDA 5${mu}ell$/ml and the normal fetus development was 2% embryos for both treatments. Results of this percent study indicated that toxicity of FDA does not affect not only the survival of fresh and vitrified mouse morulae but also the development rate and implantation of fetus after transfer as well. The development rates of mouse morulae with the FDA score of P5, P4 and P3 were 92, 67 and 42%, respectively, it was considered that FDA-test was fit for the judge of survival.

• Journal of Animal Reproduction and Biotechnology
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• v.34 no.2
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• pp.106-110
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• 2019

Sexed sperm can contribute to increase the profitability of the cow industry through the production of offspring of the craved sex, such as males for meat or females for dairy production. Therefore, the utilization of sexed sperms plays a very important role in the production of offspring of superior cattle. In this study, we examined the pregnancy rates and calves sexing proportion of male and female calves produced using AI, both performed using sexed and conventional sperm. In the result, the conception rates after ET were 73.3% (33/45) sexed semen and 52% (55/104) conventional semen. Thus, the sex ratio for sexed-semen inseminations was 70% (21/30) females for singleton births within a 272 to 292 day gestation interval. The sex ratio for conventional semen was 61% (34/56) females for births. As a result, it is suggested that the use of sex classification sperm will play a very important role in the offspring production of Korean bovine.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.7
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• pp.1116-1122
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• 1999

Raising dairy cattle for milk production has been promoted and supported by the Thai government in recent years. The extent to which dairy farmers in southern Thailand use the practices recommended by government officers is not known and was investigated in this study. With dairy farming in southern Thailand mainly concentrated in the Phatthalung province, the entire population of dairy farmers in this province was studied. A total of 114 dairy farmers were studied by personal interviews. The results showed that the farmers varied widely in their use of the practices for dairy production in southern Thailand. The study identified that the major problems in dairy production in southern Thailand were low rates of conception to artificial insemination, the high price of feedstuffs and a shortage of roughage in the dry summer months.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.6
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• pp.868-870
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• 1999

A total of 69 ovaries were collected from 345 camels slaughtered in Maiduguri abattoir, North-Eastern part of Nigeria, to study the influence of season on ovary weight and corpus luteum count in the dromedary (single humped) camel (Camelus dromedaries). Right ovary was significantly heavier (p<0.01) and had more follicular fluid than the left. Although corpus luteum count increased gradually throughout the study period, no camel had 3 active corpora lutea and only 53 out of the total number had two. Ovarian activity seem to be higher in the cold dry harmattan season, November/December, than during the warmer post rainy season, September/October. These periods can be exploited by farmers, especially peasants who rely heavily on natural mating, to obtain greater conception rates and reduce the chance of failure during mating.

• Proceedings of the Safety Management and Science Conference
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• 2000.11a
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• pp.95-99
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• 2000

The domestic ports become less competitive for the out of dated equipments and inefficient information system. Specially, Inchon Port, which is the second largest port of Korea, has the point at issue such as the excessive logistics cost because of the limit of handling capacity and the chronic demurrage. In this paper to develope the simulation programs the basic input parameters such as arrival intervals, cargo tons, service rates are analyzed and the probability density functions for there variable are estimated. Also to perform the conception of continuous berth utilization, the berth and cargo classification is reconstructed. And the more actual simulation is realized by using more detailed depth representation of water The simulation model is executed based on the knowledge base and database, and is constructed using Visual Basic and Access database. Simulation results reveal that this study suitably reflect the real berth operation and waiting time of ships is shortened.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.134-134
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• 2003

Bovine embryos produced by in vitro maturation, feretilization and development was examined for presevation and transfer. The fertilization medium used BO medium with 5 mM/$m\ell$ caffeine and 10$\mu\textrm{g}$/$m\ell$ heparin and adjusted to a pH of 7.2 to 7.4. The final concentration of spermatozoa was adjusted to 1$\times$$10^{6}$ cells/$m\ell$ motile sperm during fertilization in vitro. At 8~10 hrs after insemination, the oocytes were transferred into CR1aa medium and cultured for 7 days. Embryos were preserved by vitrification method for transfer. When the embryos of early, blastocyst and expanded blastocyst stages were frozen-thawed, the proportions of embryos with normal morphology 83.6, 88.1 and 85.2%. (중략)

• Clinical and Experimental Reproductive Medicine
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• v.12 no.2
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• pp.15-23
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• 1985

Therapy for anovulation represents one of the more gratifying and successful type of infertility management. Despite the introduction of bromocriptine, human menopausal gonadotropin (HMG), and gonadotropin releasing hormone (GnRH), clomiphene citrate remains the mainstay of ovulation induction therapy. There is wide variability in reported rates of ovulation induction (57-91%) and conception (25-43%) following clomiphene therapy. Factors contributing to this variability among different reports are the differences in dosage and duration of therapy, different criteria utilized in selecting patients for clomiphene therapy and different luteal phase parameters of presumptive ovulation. A review of recent experience with clomiphene citrate in the Department of Obstetrics and Gynecology in Seoul National University from January, 1983 to May, 1985 yields the following conclusions: 1. Ovulation rate per total patients treated was, 69.0% 2. Pregnancy rate per total patients treated was 31.7%, and that per total patients ovulated was 45.9%. 3. Ovulation rate at the dosage level up to 150 mg/day (50.3-53.8%) was somewhat higher than that at 200 mg/day or more (33.3-34.6%), and pregnancy rate per total patients treated was comparable at each dosage level. 4. Ovulation rate per total patients ovulated at each dosage level, where ovulation and conception occurred, showed a decreasing tendency as the dosage increased, but pregnancy rate per total patients conceived was comparable except at 200 mg/day. 5. Cumulative pregnancy rate per total patients conceived in each ovulatory cycle was 68.9% in 3 cycles, 88.9% in 4 cycles, and 100% in 6 cycles.