• 한국작물학회지
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• 제27권4호
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• pp.361-370
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• 1982

The effects of climatic factors on organisms lire variable and complex, and it, however, can be interpreted in terms of those on the distribution and those on the population densities. The distribution of an organism may largely be determined by the temperatures, except some temporal organisms which are depended on the air mass movements. Population density of an organism is determined by various climatic factors, such as previous winter temperature, temperature of growing season and rainfall. The start of growing season of the rice plants has been shifted to earlier since last decade in Korea. This may mean that the overall climatic condition during the growing season might be considerably different from those in past years, and such a difference in climatic conditions might have close relation with the recent status of the diseases and insect pests through direct effects on the physiology and population dynamics of the organisms, as well as through on the biotic associations of the pest organisms. The white back planthopper and brown planthopper have become the key insect pests in Korea in recent years. They are migratory and have high reproductive pontentials and more generations than average residential insects. The synchronization of the migrants and physiological condition of the rice plants seems to be the important factors in relation to the recent outbreaks of these insects; the high reproductive rate can be obtained with the growth stage of rice being 30-50 days after transplanting. The modication of the microclimate associated with high plant density and some other introduced new cultural techniques also have some relation with the outbreak. The key diseases of the rice are the blast disease, sheath blight and the bacterial leaf blight. For the rice blast, the seedling blast and leaf blast during the early growing season and the neck blast, have become more serious, the former may be related to hotbed nursery and the later may be related to the high humidity in early August, and synchronization of the heading time which has been shifted to early part from middle or late part of August. In general, for the rice diseases, the development of the new races have been the most serious which are largely resulted from the introduction of the new varieties, but it also seems to be related with the prolonged periods of the favorable condition associated with the shifted growing seasons. In general, the diseases and insect pest problems have become much more variable and complex, and control measures should be based on the thorough knowledge of the ecology of the pest organisms, that is, effects of various environmental factors on the disease cycle; spore release, spore deposition, infection, colonization and sporulation of the disease organisms, and those on the development, reproductive potentials, dispersal, age specific responses of the insects. The well organized real-time pest management systems, such as alfalfa weevil management system developed at the Purdue University in U.S., is the prime importance for the implementation of the pest management principles.

• Clinical and Experimental Reproductive Medicine
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• 제36권1호
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• pp.45-53
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• 2009

목 적: 본 연구는 정상 정액을 배양액으로 세척한 후 $4^{\circ}C$, $22^{\circ}C$, $37^{\circ}C$에서 5일 동안 보존하면서 정자의 운동성, 생존성을 관찰하여 정자의 운동성과 수명 유지를 위한 적정 배양 환경을 분석하고자 하였다. 연구방법: 정액검사 시 정상으로 판정된 남성의 정자를 HTALP 배양액으로 세척하여 정자의 최종 농도 $1{\times}10^6/ml$로 각 5 ml을 배양온도 $4^{\circ}C$, $22^{\circ}C$, $37^{\circ}C$에서 5일 동안 배양하였다. 1일, 3일 5일째에 CASA에 의해 운동성을 측정하였고, HOST로 정자막의 온전성을 분석하였으며, CTC pattern으로 수정능획득 상태 분석하여 최적의 배양 환경을 분석하였다. 결 과: 정자의 운동성, 생존성 및 수정능획득이 야기되지 않은 정자는 배양일에 따라 유의하게 감소하였다 (p<0.05). 또한 정자 배양 후 1일에는 정자의 운동성, 생존성 및 정자막의 온전성과 CTC pattern은 온도에 따라 차이가 없었으나, 배양 후 3일과 5일에서는 $22^{\circ}C$에서 배양된 정자가 다른 배양온도에 비해 가장 잘 보존되었다 (p<0.05). 결 론: HTALP로 세척된 정자를 $22^{\circ}C$에서 보존 시 5일까지 정자의 운동성과 수명을 보조생식술에 적합한 수준으로 유지시킬 수 있는 최적 배양 환경으로 제시할 수 있다.

• Asian-Australasian Journal of Animal Sciences
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• 제16권8호
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• pp.1108-1117
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• 2003

In Guadeloupe small ruminants (SR) are reared for meat production under pasture conditions. Intensive rotational grazing systems (irrigated, fertilised and high stocked) allow reasonable levels of production but generate high post-grazing residues. Experiments were designed to control them. A system in which residuals were mown (RM) was tested in comparison to the control system (Residuals Remained, RR). The same design was carried out for two years with Creole goat (G) and Martinik sheep (S). An accelerated reproductive rate (3 parturitions over 2 years) was carried out. Systems were compared at three parturition seasons per year(dry, intermediate and rainy seasons). Each group was composed of 20 goats ($36.0{\pm}2.5kg$) or 20 ewes ($46.8{\pm}2.4kg$). The female body traits did not vary according to pasture management and seasons. The stocking rate averaged 1,400 kg LW/ha. The mean fertility rate for does varied significantly (p<0.05) within the kidding season, from $80.4{\pm}0.5%$ to $93.7{\pm}2.9%$ while the mean litter size was $2.30{\pm}0.07$ total kids born. No effect of pasture system was observed. Corresponding values for ewes were $83.2{\pm}12.8%$ vs. $75.6{\pm}12.5%$ (p<0.05) and $2.43{\pm}0.24$ vs. $2.03{\pm}0.29$ (p<0.01) total lambs born for SRM and SRR ewes, respectively. A seasonal effect was observed upon ewe performances. The preweaning mortality of kids and lambs averaged 16.3% and 14.4%, respectively. It was 7 and 9 percentage points more (p<0.01) for RR than for RM kids and lambs, respectively. For both species, weaning took place at an average age of $81.4{\pm}3.6days$. In Creole kids, live weight at birth and at weaning were $1.9{\pm}0.2kg$ and $8.9{\pm}0.8kg$, respectively. In the Martinik sheep, the traits averaged $2.9{\pm}0.2kg$ and $18.9{\pm}0.9kg$. For both traits in both species, significant (p<0.05) group${\times}$season interactions were recorded. The consequences of elimination of post-grazing residues varied according to the SR species, the environmental conditions and the animal physiological status. The forage characteristics were not limiting factors since forage availability in the RM systems (2,300 and 2,600 kg DM/ha, respectively) and chemical composition were at satisfactory levels (CP content averaged 12 and 10%). It is recommended to develop new grazing system which would allow the use of post-grazing residues instead of mowing the refusals.

• Parasites, Hosts and Diseases
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• 제23권2호
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• pp.241-246
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• 1985

우리나라 8개 농촌지역의 회충 감염율, 감염 량 및 기초산란율(basic reproductive rate)등 역학적 변수의 상관관계를 관찰함으로써 우리나라 회충감염 실태를 분석하였다. 이들 감염율, 감염량 등은 대변검사는 물론 pyrantel pamoate투여후 충체 회수결과에 의해 측정하였으며 그 결과는 다음과 같다. 1. 각 조사지역의 충체양성률(감염율)은 16.5~79.5%의 범위에 있었고 이것은 대변검사에 의한 충란양성률 3.3~66.7%보다 9~18%가 높은 수치이었다. 조사대상 주민의 평균 회충 감염량은 지역에 따라 0.21에서 8.44로 나타났고 개인별 감염량 분포는 'k'치가 0.38~0.54인 부이항분포(negative binomial distribution)를 보였다. 2. 이 조사에서 나타난 충체양성률은 Anderson과 May의 수식 $p=1-(1+M^{*}/k)^{-k}$ (p : 충체양성률, $M^*$ : 평형상태의 평균 감염량)에 의해 구한 이론치와 거의 일치하여 우리나라 농촌지역의 회충감염률과 감염량의 상관관계는 이 수식에 의해 매우 정확히 표현됨을 알 수 있었다. 또 회충 암컷 1마리가 평생 산출하는 무수한 충란중 다음 숙주에 성공적으로 감염되고 성숙되는 암컷의 수를 표시하는 기초산란을(R)은 지역에 따라 1.03에서 2.11까지인 것으로 나타났다. 이상의 결과로 보아 'R'치가 1에 가까운 지역은 역학적으로 재감염의 breakpoin떼 도달하고 있는 것으로 판정되므로 회충 박멸이 매우 희망적이지만 전국적으로 'R'치가 1이하로 될 때까지 우리나라 회충관리사업은 계속되어야 할 것으로 생각된다.

• Animal Bioscience
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• 제35권12호
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• pp.1948-1956
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• 2022

Objective: This study was conducted to evaluate the effects of selenium (Se) source and level on the physiological response, reproductive performance, serum Se level, and milk composition in gestating sows. Methods: A total of 54 multiparous sows (Yorkshire×Landrace) with average body weight (BW), backfat thickness (BF), and parity were assigned to one of five treatments with 10 or 11 sows per treatment using a 2×2 factorial arrangement with one additional treatment in a completely randomized design. Inorganic or organic Se (IS or OS) sources were added to the diet at 0.30 ppm and 0.50 ppm Se. A non-Se-fortified corn-soybean meal basal diet served as a negative control. Treatments were as follows: i) Control: corn-soybean based diet, ii) IS30: control+inorganic Se 0.30 ppm, iii) IS50: control+inorganic Se 0.50 ppm, iv) OS30: control+ organic Se ppm, and v) OS50: control+organic Se 0.50 ppm. Results: At day 21 of lactation, piglet weight and weight gain in the OS treatments were higher than those in the IS treatments (p<0.05). Meanwhile, adding 0.5 ppm Se also resulted in the same significant differences in piglet BW and weight gain (p<0.05). Colostrum and milk Se concentrations increased (p<0.05) with Se level for both Se sources but were greater when sows were fed organic Se (p<0.05). Except for 24 hours postpartum, the Se concentrations were higher when sows were fed organic Se (p<0.05). Sow serum Se content was greater as Se levels increased from 0.3 ppm to 0.5 ppm at day 110 of gestation, 24 hours postpartum and day 21 of lactation (p<0.05). The pig serum Se concentration increased as the dietary Se level increased (p<0.05) and was higher when the sow dietary Se source was organic (p<0.05). Organic Se 0.5 ppm also had the highest serum Se level at two measured points (p<0.05). Conclusion: Consequently, supplementation with organic Se or 0.5 ppm Se in a gestating diet could improve piglet performance, the Se status of sows and piglets and milk composition, but organic Se at 0.5 ppm is optimal.

• Clinical and Experimental Reproductive Medicine
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• 제34권1호
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• pp.49-56
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• 2007

목 적: 성선자극호르몬과 GnRH agonist (GnRH)를 동시에 중단하는 1$\sim$2 일간의 단기 coasting이 임신율을 포함한 난소과자극증후군 예방에 미치는 효과를 조사하고자 한다. 연구방법: 체외수정시술을 위한 과배란유도 시 15 mm 이상의 난포가 20 개 이상이고 혈중 E$_2$ 농도가 4,000 pg/ml 이상일 때 coasting을 시도한 37 명의 여성들을 대상으로 하였다. Coasting은 성선자극호르몬과 GnRH agonist를 동시에 중단하였으며, 초음파상 난포의 상태와 혈중 E$_2$ 농도 에 따라 1일 또는 2일 동안 시행하였다. 혈중 E$_2$ 농도, 채취된 난자 수, 수정율, 임신율 등을 후향적으로 비교 분석하였다. 결 과: 평균 혈중 E$_2$ 농도는 coasting 시작 당일 6,993 pg/ml 에서 hCG 투여일에 3,396 pg/ml로 감소하였다. 평균 채취 난자 수와 수정율은 15.7개와 70%였다. 15명 (40.6%)이 임신을 하였고 착상율은 15.2%였다. 26명 (70.3%)이 1일, 11명 (29.7%)이 2일 동안 coasting 하였다. 평균 혈중 농도의 감소율은 1일 coasting한 군에서 43%, 2일 costing한 군은 15% (첫날)와 81% (둘째날)이었다. 임신율은 두 군간 유사하였고, 중증도 이상의 OHSS는 발생하지 않았으며 3명 (8.1%)에서 경미한 OHSS가 나타났다. 결 론: 성선자극호르몬과 GnRH agonist의 통시 중단에 의한 1$\sim$2 일의 단기 coasting은 체외수정의 결과에 영향을 주지않고 OHSS 를 예방하는데 성공적으로 적용될 수 있을 것으로 사료된다.

• 보건의료산업학회지
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• 제8권3호
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• pp.137-145
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• 2014

The objective of this study was to analyze the risk of preterm birth (PTB) and low birth weight (LBW) in extramarital birth by analyzing 2008-2012 birth certificated data (2,328,719 births) from Korea Statistics. Odds ratio and 95% confidence intervals (95% CI) were calculated from logistic regression analyses to describe the associations between PTB & LBW and extramarital birth adjusted for maternal age, maternal occupation & education, infantile sex, birth order and number of child birth (singleton & multiple birth). The rate of extramarital birth was 1.8 percent and 2.1 percent in 2010-11. The incidence of LBW was 8.1 percent in extramarital birth and 5.0 percent in marital birth. The incidence of PTB in extramarital birth were 8.2 percent and 5.8 percent in marital birth. Compared with marital birth, the odds ratio (OR) for PTB were 1.48 (95% CI: 1.43-1.54) for extramarital birth. Risk of LBW was higher in extramarital birth (OR: 1.70, 95% CI: 1.64-1.76) than that of marital birth. Among mothers younger than 20 years, the odds ratio of PTB among extramarital birth, relative to married birth was 1.69 (1.49-1.91). Among unmarried mothers, those at a higher risk of LBW was aged 20-29 years (1.69: 1.59-1.79). Maternal unmarried status was associated with increased risk of PTB and LBW.

• Reproductive and Developmental Biology
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• 제35권3호
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• pp.227-232
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• 2011

This survey was conducted to investigate the current status of swine artificial insemination(AI) centers registered as 'semen processing business' in Korea. The survey responses were collected by direct visitation or telephone conversation for 5 months from May through September in 2008. The survey showed that sixty-four AI centers were enrolled in local government and those of fifty-two AI centers were under operation. Forty-nine AI centers surveyed owned a total of 3,334 boars and the Duroc breed accounted for the highest rate(73.1%) of all boar breeds. In type of ownership, agricultural management corporations was the highest(42.3%) and followed by private ownership(34.6%). Large-scale AI centers in terms of own over 151 boar were surveyed as 5.9% and most AI centers own less than 100 boars(86.5%). The average number of boars per AI center was 68. The amount of liquid semen provided by 52 AI centers were 1,791,000 doses and each AI center provides average of 39,000 does, which is represented for 90% consumption by sows in Korea.

• Asian-Australasian Journal of Animal Sciences
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• 제25권1호
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• pp.1-16
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• 2012

Reproduction in ruminant species is a highly complex biological process requiring a dialogue between the developing conceptus (embryo-fetus and associated placental membranes) and maternal uterus which must be established during the peri-implantation period for pregnancy recognition signaling and regulation of gene expression by uterine epithelial and stromal cells. The uterus provide a microenvironment in which molecules secreted by uterine epithelia and transported into the uterine lumen represent histotroph, also known as the secretome, that are required for growth and development of the conceptus and receptivity of the uterus to implantation by the elongating conceptus. Pregnancy recognition signaling as related to sustaining the functional lifespan of the corpora lutea, is required to sustain the functional life-span of corpora lutea for production of progesterone which is essential for uterine functions supportive of implantation and placentation required for successful outcomes of pregnancy. It is within the peri-implantation period that most embryonic deaths occur in ruminants due to deficiencies attributed to uterine functions or failure of the conceptus to develop appropriately, signal pregnancy recognition and/or undergo implantation and placentation. The endocrine status of the pregnant ruminant and her nutritional status are critical for successful establishment and maintenance of pregnancy. The challenge is to understand the complexity of key mechanisms that are characteristic of successful reproduction in humans and animals and to use that knowledge to enhance fertility and reproductive health of ruminant species in livestock enterprises.

• Journal of Nutrition and Health
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• 제37권2호
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• pp.115-122
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• 2004

Adequate vitamin B$_2$ vitamin B$_{6}$, folate and vitamin B$_{12}$ nutrition is known to be important for reproductive function in women of childbearing age. The purpose of this study was to evaluate serum vitamin B$_2$ vitamin B$_{6}$, folate and vitamin B$_{12}$ status and serum homocysteine levels in 115 women aged 33.2$\pm$4.0 years, who had been diagnosed with infertility, and 49 women aged 34.5$\pm$3.8 years having at least one born child. Total vitamin B$_2$ and vitamin B$_{6}$ intakes in infertile women were significantly lower than those in control. Serum vitamin B$_2$ vitamin B$_{6}$, folate and vitamin B$_{12}$ concentrations were significantly lower in infertile women than those in control and serum homocysteine levels were significantly higher in infertile women than those in control. Thirteen percent in infertile women and zero percent in control were assessed as hyperhomocysteinemic and there was a significant difference in the prevalence of hyperhomocysteinemia between infertile women and control. 41% infertile women were assessed as folate deficiency. Serum folate concentrations was negatively correlated with serum homocysteine of the infertile women and control. Total vitamin B$_2$ intakes was negatively correlated with serum homocysteine of the infertile women and control. Total vitamin B$_{6}$, folate intakes were negatively correlated with homocysteine of infertile women only. In conclusion, infertile women are needed to intake more B vitamins intakes. Furthermore researches are needed to estimate adequate B vitamin supplementation in infertile women. (Korean J Nutrition 37(2): 115-122, 2004): 115-122, 2004)