• Journal of Veterinary Clinics
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• v.37 no.6
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• pp.301-304
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• 2020

The gestation period and parturition days were accurately predicted by measuring progesterone concentration in the plasma from 40 pregnant companion bitches. The mean length of the estrous cycle based on plasma progesterone concentrations were 8.14 ± 1.39 (Mean ± SD) days for proestrus, 9.19 ± 2.01 days for estrus, and 55.38 ± 1.96 days for diestrus phase, respectively. The gestation length from each based on the days was 65.61 ± 2.47 days from the first day of estrus after the first vaginal discharge, 63.21 ± 0.99 days from the day when plasma progesterone concentrations increase above 4.0 ng/ml, and 54.51 ± 3.51 days from the first day of diestrus, respectively. Therefore, the parturition day was estimated 65 days from the first day of estrus after the first vaginal discharge, 63 days from the day when plasma progesterone concentrations increase above 4.0 ng/ml, and 54 days from the first day of diestrus, respectively.

• Journal of Animal Science and Technology
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• v.65 no.3
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• pp.627-637
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• 2023

As the population and income levels rise, meat consumption steadily increases annually. However, the number of farms and farmers producing meat decrease during the same period, reducing meat sufficiency. Information and Communications Technology (ICT) has begun to be applied to reduce labor and production costs of livestock farms and improve productivity. This technology can be used for rapid pregnancy diagnosis of sows; the location and size of the gestation sacs of sows are directly related to the productivity of the farm. In this study, a system proposes to determine the number of gestation sacs of sows from ultrasound images. The system used the YOLOv7-E6E model, changing the activation function from sigmoid-weighted linear unit (SiLU) to a multi-activation function (SiLU + Mish). Also, the upsampling method was modified from nearest to bicubic to improve performance. The model trained with the original model using the original data achieved mean average precision of 86.3%. When the proposed multi-activation function, upsampling, and AutoAugment were applied, the performance improved by 0.3%, 0.9%, and 0.9%, respectively. When all three proposed methods were simultaneously applied, a significant performance improvement of 3.5% to 89.8% was achieved.

• Toxicological Research
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• v.13 no.1_2
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• pp.175-182
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• 1997

LBD-001, a recombinant human interferon $\gamma$ produced by genetically engineered yeast as a host system, was intravenously administered to pregnant female rats (Sprague-Dawley) from day 17 of gestation to day 21 of lactation at dose levels.of $0.35 \times 10^6$, $0.69 \times 10^6$, and $1.38 \times 10^6$ I.U./kg/day. In vasopressin-treated group, vasopressin (5 I.U./kg/day) was intravenously injected only for 5 days of perinatal period. (1) No signicant changes by the treatment of LBD-001 were observed in the body weights, food and water consumption, feeding and nurshing behaviors, and the weights of main organs of mother rats. In vasopressin-treated group, no significant changes were observed except the decrease in the food consumption on day 18 of gestation and one case of abnormal offspring with bleeding spots on the skin. (2) No significant changes in the body weights, survival rates, locomotor activity, emotional development. and the motor coordination of offsprings (F1) by the treatment of LBD-001 were observed except the fact that increase of ambulation in the female offsprings of LBD-001 ($0.69 \times 10^6$ or $1.38 \times 10^6$ I.U./kg/day)-treated groups and the increase of rearing in the males of LBD-($1.38 \times 10^6$ I.U./kg/day)-treated group, and the increase of the weight of liver and ovaries in the female offsprings in the LBD-001 ($1.38 \times 10^6$ I.U./kg/day)-treated group were observed. Altogether, the results show that LBD-001 at the dose of $1.38 \times 10^6$ I.U./kg/day or less does not significantly affect the mother rats and their offsprings (F1) except the minor influences when treated during the perinatal and postnatal period.

• Journal of Technology Innovation
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• v.22 no.1
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• pp.1-22
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• 2014

R&D investment also has a gestation period similar to other investments in economics. The gestation period originates from time lag effect of input and output. Thus it is necessary to consider time lag effects when analyzing the relationship between firms' R&D investment and R&D performance. The main objective of this research is to estimate the length of time lag effect of R&D investment. The Almon distribution lag model was applied to estimate the time lag effect. The firm level panel dataset was established from 2002 to 2009. The net value of R&D investment and the number of patent applications were used to measure R&D input and output, respectively. This method found the estimated time lag to be 1~2 years across all datasets. The same analyses were applied to chemical, metal, electronic, exact science, and machinery industries' data. And we found there were differences among sectors in regard to the time lag effect.

• Korean Journal of Veterinary Research
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• v.42 no.4
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• pp.443-449
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• 2002

The morphological studies on the rectal development in the 60-, 90- and 120-day-old fetuses and neonates of Korean native goats were investigated by light microscopy and scanning electron microscopy. The rectal wall appeared to be differentiated into the epithelium, lamina propria, tunica muscularis and serosa in 60-day-old fetus. The rectal epithelia were stratified in some areas and simple columnar in others at 60- and 90-day-old fetuses but was only observed simple columnar epithelium at 120-day-old fetus. The goblet cells and the intestinal glands appeared in the rectal mucosa at 90-day-old fetus and gradually increase in number during gestation period. The rectal villi appeared at 60-day-old fetus and increased in length and width until 90-day-old fetus but the villi appeared to be shorter and degenerated after 120-day-old fetus. Only the rudiment trace of the villi remained at birth. The tunica muscularis of the rectum were continuously developed during gestation period. The inner circular and outer longitudinal muscle layers of rectum were observed in the 120-day-old fetuses. Under scanning electron microsoopy, the rectal villi appeared at 60-day-old fetus. The pentagonal/hexagonal microridges and numerous microvilli were observed on the luminal surface of rectal wall. Low and thumb-like rectal villi were developed at 90-day-old fetus. The rectal villi became degenerated after 120-day-old fetus. Only the rudiment of villi was remained at birth. Many circular folds were well developed. Opening portions of intestinal glands appeared like slot.

• Korean Journal of Veterinary Research
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• v.31 no.4
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• pp.529-534
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• 1991

Plasma progesterone concentrations were measured from 97 Che-ju native mares throughout the estrous cycle, Day 20 to 23, 5 to7 months of pregnancy, and gestation period (<1 to 7 months) using the radioimmunoassay techniques for pregnancy diagnosis. Plasma progesterone concentrations during the estrous cycle were the lowest (<1.0ng/ml) at estrus, remained high from 9 to 18 days (3.7~7.6ng/ml) and drastically decreased thereafter to reach minimal concentrations at the next estrus. Plasma progesterone concentrations at Day 21 to 24 were a significantly different between in pregnant mares (>5.7ng/ml) and in non-pregnant mares (<1.0ng/ml). The accuracy of the pregnancy diagnosis based on plasma progesterone concentrations at Day 20 to 23 was 86.7% for positive and 100% for negative, whereas on 5 to 7 months was 66.7% for positive and 71.0% for negative, respectively. Plasma progesterone concentrations during the gestation period(1 to 7 months) increased after 1 month of pregnancy, with peak concentrations(>8.0ng/ml) occurring between 60 to 100 days of pregnancy, and decreased below 1.7ng/ml after 6 months of pregnancy.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.4
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• pp.540-572
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• 2011

The present review focuses on the effects of energy intake on performance, changes in body tissue during lactation, and metabolic parameters in dairy cows. Especially, pre-partum nutrition and its influence on lactation are emphasized. In recent decades the increase in genetic potential of dairy cows has increased milk yield. This fact sharpens the problem of a negative energy balance in early lactation because the amount of energy required for maintenance and milk production exceeds the amount of energy cows can consume. Around parturition, reduced feed intake reinforces the situation. Continuing negative energy balance causes decreasing milk yield, fertility problems, and incidence of metabolic diseases. Hence, the cow has to rely on body reserves that were stored in late lactation and the dry period. It is evident that the nutritional status pre-partum acts as the key factor for milk yield and fertility parameters in the following lactation. Cows overfed during the foregoing gestation and which have gained large quantities of body fat have lower dry matter intake along with the need to mobilize larger quantities of body reserves in lactation. The milk yield in the following lactation is lower than in cows fed according to their requirements. Cows restrictively fed in late gestation have a higher feed intake in lactation and a lower mobilization of body reserves. The effect of energy intake post-partum plays only a minor role for performance parameters in lactation. Lipid mobilized from body reserves makes a substantial contribution to the energetic cost of milk production in early lactation and adipose tissue undergoes specific metabolic alterations. Adipose tissue is degraded to free fatty acids, which are used in liver for energy purposes. High lipid mobilisation promotes the development of a fatty liver and therefore a reduced gluconeogenesis.

• Journal of Embryo Transfer
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• v.14 no.2
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• pp.121-129
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• 1999

The objective of this study was to produce calves by transfer of embryos derived from slaughter house(SHD) and ultrasound-guided ovum pick-up (OPU). At 60 hrs after injection of 400 mg FSH dissolved in 25% polyvinylpyrrolidone(PVP) by single dose, ultrasound-guided follicular oocyte aspiration was ferformed. Day-7 and day-8 blastocysts produced by in vitro maturation (IVM), fertilization (IVF) and culture(IVC) of the oocytes derived from SHD and OPU were nonsurgically transferred into recipients. The results obtained were as follows. The cleavage rate and the development rate to blastocysts were not significantly (P<0.05) different between the oocytes obtained by SHD (72.9% vs. 34.1%) and OPU (75.9% vs. 38.4%). The oocyte recovery rate from the number of follicles by ultrasound-guided aspiration were not significantly (P<0.05) different between Holstein (61.7%) and Hanwoo (60.1%), but the rate of oocytes useful for IVF was significantly (P<0.05) higher in Hanwoo (69.3%) than Holstein (59.6%). The cleavage rate and the development rate to blastocysts was not significantly (P<0.05) different between Holstein (74.9% vs. 39.2%) and recipients on day 8 of estrus cycle resulted in 13 pregnancies (34.2%). One of them was sacrificed during gestation period due to mastitis and another was aborted spontaneous. The resulting 14 calves were morphologically normal at birth. Seventy eight fresh OPU-IVF embryos were transferred into 21 recipients on day 8 of estrus cycles, resulting in pregnancy of 12 recipients (41.4%). Two of them were sacrificed during gestation period due to mastitis and the other two were aborted. Nevertheless, the 11 OPU-calves have been born normally.

• Journal of Animal Reproduction and Biotechnology
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• v.38 no.2
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• pp.84-88
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• 2023

Because multiple ovulation embryo transfer (MOET) in cattle includes several benefits such as wide spreading of genetically superior offspring for long distance, this biotechnological method has been widely applied to Hanwoo. When the recipients are not stayed close after embryo recovery from donor, the embryos are moved to other farms via several vehicles (car, train, and airplane). However, air travel induces lesser oxygen level, increased vibration, lower air pressure, higher noise, and increased exposure of cosmic radiation to living things than ground level. It was still unknown that fresh embryos obtained from multiple ovulation of Hanwoo could maintain their fertility after being transported via air plane, the present case report introduced a clinical case of MOET in Hanwoo after shipping fresh embryos via air transportation. The donor was multi-ovulated via follicle-stimulating hormone series of injection, which was followed by a gonadotrophin-releasing hormone injection and artificial insemination twice. The embryos were recovered by the uterine flushing, packed in ministraws, transported to recipients for 6 h including 1 h air flight, and then transferred to the synchronized recipients. During pregnancy diagnosis of early gestation period, 5 of 7 recipients (71.4%) presented no heat signs and showed fetal sacs with fluid under transrectal ultrasonography. After normal gestation period, all recipients naturally delivered healthy calves (male n = 2 and female n = 3) without abortion, stillbirth, and premature birth. The present case report indicated that transportation of fresh embryos for MOET via domestic flight in Korea did not affect to their fertility.

• Journal of Nutrition and Health
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• v.14 no.2
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• pp.105-116
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• 1981

A quantitative restriction of maternal diet without changes in quality of diet was given to the Sprague Dawley rats during the third week of gestation and lactation. Half the normal average daily intake of control group was given to deficient groups in this period. Female rats of control group were fed a commercial diet ad libitum throughout the experimental period. Dietary restriction started from birth to weaning in deficient I group and from the 15th day of gestation to weaning in deficient II group. Body and brain weight of offsprings of deficient groups were significantly lower than control group, but the ratios of brain weight to body weight in deficient groups were higher than the control group. Significant difference between deficient groups (I and II) was noticed at weaning. Brain DNA, RNA and total protein of offsprings of deficient groups were significantly lower than control group, but RNA/DNA, brain weight/DNA, and total protein/DNA show that cell number were more affected than the cell size by the maternal dietary restriction during the third week of gestation and lactation. Between the deficient groups, there was a significant difference in brain DNA and RNA, but no significant difference in total brain protein. (This research was supported in part by grant from the Ministry of Education.)